text: /* attrs.c -- recognize HTML attributes
  
    (c) 1998-2009 (W3C) MIT, ERCIM, Keio University
    See tidy.h for the copyright notice.
  
  */
  
  #include "tidy-int.h"
  #include "attrs.h"
  #include "message.h"
  #include "tmbstr.h"
  #include "utf8.h"
  
  /*
   Bind attribute types to procedures to check values.
   You can add new procedures for better validation
   and each procedure has access to the node in which
   the attribute occurred as well as the attribute name
   and its value.
  
   By default, attributes are checked without regard
   to the element they are found on. You have the choice
   of making the procedure test which element is involved
   or in writing methods for each element which controls
   exactly how the attributes of that element are checked.
   This latter approach is best for detecting the absence
   of required attributes.
  */
  
  static AttrCheck CheckAction;
  static AttrCheck CheckScript;
  static AttrCheck CheckName;
  static AttrCheck CheckId;
  static AttrCheck CheckIs;
  static AttrCheck CheckAlign;
  static AttrCheck CheckValign;
  static AttrCheck CheckBool;
  static AttrCheck CheckLength;
  static AttrCheck CheckTarget;
  static AttrCheck CheckFsubmit;
  static AttrCheck CheckClear;
  static AttrCheck CheckShape;
  static AttrCheck CheckNumber;
  static AttrCheck CheckScope;
  static AttrCheck CheckColor;
  static AttrCheck CheckVType;
  static AttrCheck CheckScroll;
  static AttrCheck CheckTextDir;
  static AttrCheck CheckLang;
  static AttrCheck CheckLoading;
  static AttrCheck CheckType;
  static AttrCheck CheckRDFaSafeCURIE;
  static AttrCheck CheckRDFaTerm;
  static AttrCheck CheckRDFaPrefix;
  static AttrCheck CheckDecimal;
  static AttrCheck CheckSvgAttr;
  
  #define CH_PCDATA      NULL
  #define CH_CHARSET     NULL
  #define CH_TYPE        CheckType
  #define CH_XTYPE       NULL
  #define CH_CHARACTER   NULL
  #define CH_URLS        NULL
  #define CH_URL         TY_(CheckUrl)
  #define CH_SCRIPT      CheckScript
  #define CH_ALIGN       CheckAlign
  #define CH_VALIGN      CheckValign
  #define CH_COLOR       CheckColor
  #define CH_CLEAR       CheckClear
  #define CH_BORDER      CheckBool     /* kludge */
  #define CH_LANG        CheckLang
  #define CH_LOADING     CheckLoading
  #define CH_BOOL        CheckBool
  #define CH_COLS        NULL
  #define CH_NUMBER      CheckNumber
  #define CH_LENGTH      CheckLength
  #define CH_COORDS      NULL
  #define CH_DATE        NULL
  #define CH_TEXTDIR     CheckTextDir
  #define CH_IDREFS      NULL
  #define CH_IDREF       NULL
  #define CH_IDDEF       CheckId
  #define CH_ISDEF       CheckIs
  #define CH_NAME        CheckName
  #define CH_TFRAME      NULL
  #define CH_FBORDER     NULL
  #define CH_MEDIA       NULL
  #define CH_FSUBMIT     CheckFsubmit
  #define CH_LINKTYPES   NULL
  #define CH_TRULES      NULL
  #define CH_SCOPE       CheckScope
  #define CH_SHAPE       CheckShape
  #define CH_SCROLL      CheckScroll
  #define CH_TARGET      CheckTarget
  #define CH_VTYPE       CheckVType
  #define CH_ACTION      CheckAction
  #define CH_RDFAPREFIX  CheckRDFaPrefix
  #define CH_RDFASCURIE  CheckRDFaSafeCURIE
  #define CH_RDFASCURIES CheckRDFaSafeCURIE
  #define CH_RDFATERM    CheckRDFaTerm
  #define CH_RDFATERMS   CheckRDFaTerm
  #define CH_DECIMAL     CheckDecimal
  #define CH_SVG         CheckSvgAttr
  
  /*
     WARNING: This table /must/ be kept in the EXACT order of the TidyAttrId enum!
     When running the DEBUG version, this order is checked, in TY_(InitAttrs)(doc),
     and there is an assert() if any difference found.
  */
  static const Attribute attribute_defs [] =
  {
    { TidyAttr_UNKNOWN,                 "unknown!",                NULL         }, 
    { TidyAttr_ABBR,                    "abbr",                    CH_PCDATA    }, 
    { TidyAttr_ACCEPT,                  "accept",                  CH_XTYPE     }, 
    { TidyAttr_ACCEPT_CHARSET,          "accept-charset",          CH_CHARSET   }, 
    { TidyAttr_ACCESSKEY,               "accesskey",               CH_CHARACTER }, 
    { TidyAttr_ACTION,                  "action",                  CH_ACTION    }, 
    { TidyAttr_ADD_DATE,                "add_date",                CH_PCDATA    }, /* A */
    { TidyAttr_ALIGN,                   "align",                   CH_ALIGN     }, /* varies by element */
    { TidyAttr_ALINK,                   "alink",                   CH_COLOR     }, 
    { TidyAttr_ALLOWFULLSCREEN,         "allowfullscreen",         CH_BOOL      },
    { TidyAttr_ALT,                     "alt",                     CH_PCDATA    }, /* nowrap */
    { TidyAttr_ARCHIVE,                 "archive",                 CH_URLS      }, /* space or comma separated list */
    { TidyAttr_AXIS,                    "axis",                    CH_PCDATA    }, 
    { TidyAttr_BACKGROUND,              "background",              CH_URL       }, 
    { TidyAttr_BGCOLOR,                 "bgcolor",                 CH_COLOR     }, 
    { TidyAttr_BGPROPERTIES,            "bgproperties",            CH_PCDATA    }, /* BODY "fixed" fixes background */
    { TidyAttr_BORDER,                  "border",                  CH_BORDER    }, /* like LENGTH + "border" */
    { TidyAttr_BORDERCOLOR,             "bordercolor",             CH_COLOR     }, /* used on TABLE */
    { TidyAttr_BOTTOMMARGIN,            "bottommargin",            CH_NUMBER    }, /* used on BODY */
    { TidyAttr_CELLPADDING,             "cellpadding",             CH_LENGTH    }, /* % or pixel values */
    { TidyAttr_CELLSPACING,             "cellspacing",             CH_LENGTH    }, 
    { TidyAttr_CHAR,                    "char",                    CH_CHARACTER }, 
    { TidyAttr_CHAROFF,                 "charoff",                 CH_LENGTH    }, 
    { TidyAttr_CHARSET,                 "charset",                 CH_CHARSET   }, 
    { TidyAttr_CHECKED,                 "checked",                 CH_BOOL      }, /* i.e. "checked" or absent */
    { TidyAttr_CITE,                    "cite",                    CH_URL       }, 
    { TidyAttr_CLASS,                   "class",                   CH_PCDATA    }, 
    { TidyAttr_CLASSID,                 "classid",                 CH_URL       }, 
    { TidyAttr_CLEAR,                   "clear",                   CH_CLEAR     }, /* BR: left, right, all */
    { TidyAttr_CODE,                    "code",                    CH_PCDATA    }, /* APPLET */
    { TidyAttr_CODEBASE,                "codebase",                CH_URL       }, /* OBJECT */
    { TidyAttr_CODETYPE,                "codetype",                CH_XTYPE     }, /* OBJECT */
    { TidyAttr_COLOR,                   "color",                   CH_COLOR     }, /* BASEFONT, FONT */
    { TidyAttr_COLS,                    "cols",                    CH_COLS      }, /* TABLE & FRAMESET */
    { TidyAttr_COLSPAN,                 "colspan",                 CH_NUMBER    }, 
    { TidyAttr_COMPACT,                 "compact",                 CH_BOOL      }, /* lists */
    { TidyAttr_CONTENT,                 "content",                 CH_PCDATA    }, 
    { TidyAttr_COORDS,                  "coords",                  CH_COORDS    }, /* AREA, A */
    { TidyAttr_DATA,                    "data",                    CH_URL       }, /* OBJECT */
    { TidyAttr_DATAFLD,                 "datafld",                 CH_PCDATA    }, /* used on DIV, IMG */
    { TidyAttr_DATAFORMATAS,            "dataformatas",            CH_PCDATA    }, /* used on DIV, IMG */
    { TidyAttr_DATAPAGESIZE,            "datapagesize",            CH_NUMBER    }, /* used on DIV, IMG */
    { TidyAttr_DATASRC,                 "datasrc",                 CH_URL       }, /* used on TABLE */
    { TidyAttr_DATETIME,                "datetime",                CH_DATE      }, /* INS, DEL */
    { TidyAttr_DECLARE,                 "declare",                 CH_BOOL      }, /* OBJECT */
    { TidyAttr_DEFER,                   "defer",                   CH_BOOL      }, /* SCRIPT */
    { TidyAttr_DIR,                     "dir",                     CH_TEXTDIR   }, /* ltr, rtl or auto */
    { TidyAttr_DISABLED,                "disabled",                CH_BOOL      }, /* form fields */
    { TidyAttr_DOWNLOAD,                "download",                CH_PCDATA    }, /* anchor */
    { TidyAttr_ENCODING,                "encoding",                CH_PCDATA    }, /* <?xml?> */
    { TidyAttr_ENCTYPE,                 "enctype",                 CH_XTYPE     }, /* FORM */
    { TidyAttr_FACE,                    "face",                    CH_PCDATA    }, /* BASEFONT, FONT */
    { TidyAttr_FOR,                     "for",                     CH_IDREF     }, /* LABEL */
    { TidyAttr_FRAME,                   "frame",                   CH_TFRAME    }, /* TABLE */
    { TidyAttr_FRAMEBORDER,             "frameborder",             CH_FBORDER   }, /* 0 or 1 */
    { TidyAttr_FRAMESPACING,            "framespacing",            CH_NUMBER    }, 
    { TidyAttr_GRIDX,                   "gridx",                   CH_NUMBER    }, /* TABLE Adobe golive*/
    { TidyAttr_GRIDY,                   "gridy",                   CH_NUMBER    }, /* TABLE Adobe golive */
    { TidyAttr_HEADERS,                 "headers",                 CH_IDREFS    }, /* table cells */
    { TidyAttr_HEIGHT,                  "height",                  CH_LENGTH    }, /* pixels only for TH/TD */
    { TidyAttr_HREF,                    "href",                    CH_URL       }, /* A, AREA, LINK and BASE */
    { TidyAttr_HREFLANG,                "hreflang",                CH_LANG      }, /* A, LINK */
    { TidyAttr_HSPACE,                  "hspace",                  CH_NUMBER    }, /* APPLET, IMG, OBJECT */
    { TidyAttr_HTTP_EQUIV,              "http-equiv",              CH_PCDATA    }, /* META */
    { TidyAttr_ID,                      "id",                      CH_IDDEF     }, 
    { TidyAttr_IS,                      "is",                      CH_ISDEF     },
    { TidyAttr_ISMAP,                   "ismap",                   CH_BOOL      }, /* IMG */
    { TidyAttr_ITEMID,                  "itemid",                  CH_PCDATA    },
    { TidyAttr_ITEMPROP,                "itemprop",                CH_PCDATA    },
    { TidyAttr_ITEMREF,                 "itemref",                 CH_PCDATA    },
    { TidyAttr_ITEMSCOPE,               "itemscope",               CH_BOOL      },
    { TidyAttr_ITEMTYPE,                "itemtype",                CH_URL       },
    { TidyAttr_LABEL,                   "label",                   CH_PCDATA    }, /* OPT, OPTGROUP */
    { TidyAttr_LANG,                    "lang",                    CH_LANG      }, 
    { TidyAttr_LANGUAGE,                "language",                CH_PCDATA    }, /* SCRIPT */
    { TidyAttr_LAST_MODIFIED,           "last_modified",           CH_PCDATA    }, /* A */
    { TidyAttr_LAST_VISIT,              "last_visit",              CH_PCDATA    }, /* A */
    { TidyAttr_LEFTMARGIN,              "leftmargin",              CH_NUMBER    }, /* used on BODY */
    { TidyAttr_LINK,                    "link",                    CH_COLOR     }, /* BODY */
    { TidyAttr_LONGDESC,                "longdesc",                CH_URL       }, /* IMG */
    { TidyAttr_LOWSRC,                  "lowsrc",                  CH_URL       }, /* IMG */
    { TidyAttr_MARGINHEIGHT,            "marginheight",            CH_NUMBER    }, /* FRAME, IFRAME, BODY */
    { TidyAttr_MARGINWIDTH,             "marginwidth",             CH_NUMBER    }, /* ditto */
    { TidyAttr_MAXLENGTH,               "maxlength",               CH_NUMBER    }, /* INPUT */
    { TidyAttr_MEDIA,                   "media",                   CH_MEDIA     }, /* STYLE, LINK */
    { TidyAttr_METHOD,                  "method",                  CH_FSUBMIT   }, /* FORM: get or post */
    { TidyAttr_MULTIPLE,                "multiple",                CH_BOOL      }, /* SELECT */
    { TidyAttr_NAME,                    "name",                    CH_NAME      }, 
    { TidyAttr_NOHREF,                  "nohref",                  CH_BOOL      }, /* AREA */
    { TidyAttr_NORESIZE,                "noresize",                CH_BOOL      }, /* FRAME */
    { TidyAttr_NOSHADE,                 "noshade",                 CH_BOOL      }, /* HR */
    { TidyAttr_NOWRAP,                  "nowrap",                  CH_BOOL      }, /* table cells */
    { TidyAttr_OBJECT,                  "object",                  CH_PCDATA    }, /* APPLET */
    { TidyAttr_OnAFTERUPDATE,           "onafterupdate",           CH_SCRIPT    }, 
    { TidyAttr_OnBEFOREUNLOAD,          "onbeforeunload",          CH_SCRIPT    }, 
    { TidyAttr_OnBEFOREUPDATE,          "onbeforeupdate",          CH_SCRIPT    }, 
    { TidyAttr_OnBLUR,                  "onblur",                  CH_SCRIPT    }, /* event */
    { TidyAttr_OnCHANGE,                "onchange",                CH_SCRIPT    }, /* event */
    { TidyAttr_OnCLICK,                 "onclick",                 CH_SCRIPT    }, /* event */
    { TidyAttr_OnDATAAVAILABLE,         "ondataavailable",         CH_SCRIPT    }, /* object, applet */
    { TidyAttr_OnDATASETCHANGED,        "ondatasetchanged",        CH_SCRIPT    }, /* object, applet */
    { TidyAttr_OnDATASETCOMPLETE,       "ondatasetcomplete",       CH_SCRIPT    }, 
    { TidyAttr_OnDBLCLICK,              "ondblclick",              CH_SCRIPT    }, /* event */
    { TidyAttr_OnERRORUPDATE,           "onerrorupdate",           CH_SCRIPT    }, /* form fields */
    { TidyAttr_OnFOCUS,                 "onfocus",                 CH_SCRIPT    }, /* event */
    { TidyAttr_OnKEYDOWN,               "onkeydown",               CH_SCRIPT    }, /* event */
    { TidyAttr_OnKEYPRESS,              "onkeypress",              CH_SCRIPT    }, /* event */
    { TidyAttr_OnKEYUP,                 "onkeyup",                 CH_SCRIPT    }, /* event */
    { TidyAttr_OnLOAD,                  "onload",                  CH_SCRIPT    }, /* event */
    { TidyAttr_OnMOUSEDOWN,             "onmousedown",             CH_SCRIPT    }, /* event */
    { TidyAttr_OnMOUSEMOVE,             "onmousemove",             CH_SCRIPT    }, /* event */
    { TidyAttr_OnMOUSEOUT,              "onmouseout",              CH_SCRIPT    }, /* event */
    { TidyAttr_OnMOUSEOVER,             "onmouseover",             CH_SCRIPT    }, /* event */
    { TidyAttr_OnMOUSEUP,               "onmouseup",               CH_SCRIPT    }, /* event */
    { TidyAttr_OnRESET,                 "onreset",                 CH_SCRIPT    }, /* event */
    { TidyAttr_OnROWENTER,              "onrowenter",              CH_SCRIPT    }, /* form fields */
    { TidyAttr_OnROWEXIT,               "onrowexit",               CH_SCRIPT    }, /* form fields */
    { TidyAttr_OnSELECT,                "onselect",                CH_SCRIPT    }, /* event */
    { TidyAttr_OnSUBMIT,                "onsubmit",                CH_SCRIPT    }, /* event */
    { TidyAttr_OnUNLOAD,                "onunload",                CH_SCRIPT    }, /* event */
    { TidyAttr_PROFILE,                 "profile",                 CH_URL       }, /* HEAD */
    { TidyAttr_PROMPT,                  "prompt",                  CH_PCDATA    }, /* ISINDEX */
    { TidyAttr_RBSPAN,                  "rbspan",                  CH_NUMBER    }, /* ruby markup */
    { TidyAttr_READONLY,                "readonly",                CH_BOOL      }, /* form fields */
    { TidyAttr_REL,                     "rel",                     CH_LINKTYPES }, 
    { TidyAttr_REV,                     "rev",                     CH_LINKTYPES }, 
    { TidyAttr_RIGHTMARGIN,             "rightmargin",             CH_NUMBER    }, /* used on BODY */
    { TidyAttr_ROLE,                    "role",                    CH_PCDATA    },
    { TidyAttr_ROWS,                    "rows",                    CH_NUMBER    }, /* TEXTAREA */
    { TidyAttr_ROWSPAN,                 "rowspan",                 CH_NUMBER    }, /* table cells */
    { TidyAttr_RULES,                   "rules",                   CH_TRULES    }, /* TABLE */
    { TidyAttr_SCHEME,                  "scheme",                  CH_PCDATA    }, /* META */
    { TidyAttr_SCOPE,                   "scope",                   CH_SCOPE     }, /* table cells */
    { TidyAttr_SCROLLING,               "scrolling",               CH_SCROLL    }, /* yes, no or auto */
    { TidyAttr_SELECTED,                "selected",                CH_BOOL      }, /* OPTION */
    { TidyAttr_SHAPE,                   "shape",                   CH_SHAPE     }, /* AREA, A */
    { TidyAttr_SHOWGRID,                "showgrid",                CH_BOOL      }, /* TABLE Adobe golive */
    { TidyAttr_SHOWGRIDX,               "showgridx",               CH_BOOL      }, /* TABLE Adobe golive*/
    { TidyAttr_SHOWGRIDY,               "showgridy",               CH_BOOL      }, /* TABLE Adobe golive*/
    { TidyAttr_SIZE,                    "size",                    CH_NUMBER    }, /* HR, FONT, BASEFONT, SELECT */
    { TidyAttr_SPAN,                    "span",                    CH_NUMBER    }, /* COL, COLGROUP */
    { TidyAttr_SRC,                     "src",                     CH_URL       }, /* IMG, FRAME, IFRAME */
    { TidyAttr_SRCSET,                  "srcset",                  CH_PCDATA    }, /* IMG (HTML5) */
    { TidyAttr_STANDBY,                 "standby",                 CH_PCDATA    }, /* OBJECT */
    { TidyAttr_START,                   "start",                   CH_NUMBER    }, /* OL */
    { TidyAttr_STYLE,                   "style",                   CH_PCDATA    }, 
    { TidyAttr_SUMMARY,                 "summary",                 CH_PCDATA    }, /* TABLE */
    { TidyAttr_TABINDEX,                "tabindex",                CH_NUMBER    }, /* fields, OBJECT  and A */
    { TidyAttr_TARGET,                  "target",                  CH_TARGET    }, /* names a frame/window */
    { TidyAttr_TEXT,                    "text",                    CH_COLOR     }, /* BODY */
    { TidyAttr_TITLE,                   "title",                   CH_PCDATA    }, /* text tool tip */
    { TidyAttr_TOPMARGIN,               "topmargin",               CH_NUMBER    }, /* used on BODY */
    { TidyAttr_TRANSLATE,               "translate",               CH_BOOL      }, /* HTML5 global attribute */
    { TidyAttr_TYPE,                    "type",                    CH_TYPE      }, /* also used by SPACER */
    { TidyAttr_USEMAP,                  "usemap",                  CH_URL       }, /* things with images */
    { TidyAttr_VALIGN,                  "valign",                  CH_VALIGN    }, 
    { TidyAttr_VALUE,                   "value",                   CH_PCDATA    }, 
    { TidyAttr_VALUETYPE,               "valuetype",               CH_VTYPE     }, /* PARAM: data, ref, object */
    { TidyAttr_VERSION,                 "version",                 CH_PCDATA    }, /* HTML <?xml?> */
    { TidyAttr_VLINK,                   "vlink",                   CH_COLOR     }, /* BODY */
    { TidyAttr_VSPACE,                  "vspace",                  CH_NUMBER    }, /* IMG, OBJECT, APPLET */
    { TidyAttr_WIDTH,                   "width",                   CH_LENGTH    }, /* pixels only for TD/TH */
    { TidyAttr_WRAP,                    "wrap",                    CH_PCDATA    }, /* textarea */
    { TidyAttr_XML_LANG,                "xml:lang",                CH_LANG      }, /* XML language */
    { TidyAttr_XML_SPACE,               "xml:space",               CH_PCDATA    }, /* XML white space */
  
    /* todo: VERS_ALL is wrong! */
    { TidyAttr_XMLNS,                   "xmlns",                   CH_PCDATA    }, /* name space */
    { TidyAttr_EVENT,                   "event",                   CH_PCDATA    }, /* reserved for <script> */
    { TidyAttr_METHODS,                 "methods",                 CH_PCDATA    }, /* for <a>, never implemented */
    { TidyAttr_N,                       "n",                       CH_PCDATA    }, /* for <nextid> */
    { TidyAttr_SDAFORM,                 "sdaform",                 CH_PCDATA    }, /* SDATA attribute in HTML 2.0 */
    { TidyAttr_SDAPREF,                 "sdapref",                 CH_PCDATA    }, /* SDATA attribute in HTML 2.0 */
    { TidyAttr_SDASUFF,                 "sdasuff",                 CH_PCDATA    }, /* SDATA attribute in HTML 2.0 */
    { TidyAttr_URN,                     "urn",                     CH_PCDATA    }, /* for <a>, never implemented */
  
    /* HTML5 */
    { TidyAttr_ASYNC,                   "async",                   CH_BOOL     }, /* <script src="..." async> */
    { TidyAttr_AUTOCOMPLETE,            "autocomplete",            CH_PCDATA   },
    { TidyAttr_AUTOFOCUS,               "autofocus",               CH_PCDATA   },
    { TidyAttr_AUTOPLAY,                "autoplay",                CH_PCDATA   },
    { TidyAttr_CHALLENGE,               "challenge",               CH_PCDATA   },
    { TidyAttr_CONTENTEDITABLE,         "contenteditable",         CH_PCDATA   },
    { TidyAttr_CONTEXTMENU,             "contextmenu",             CH_PCDATA   },
    { TidyAttr_CONTROLS,                "controls",                CH_PCDATA   },
    { TidyAttr_CROSSORIGIN,             "crossorigin",             CH_PCDATA   },
    { TidyAttr_DEFAULT,                 "default",                 CH_PCDATA   },
    { TidyAttr_DIRNAME,                 "dirname",                 CH_PCDATA   },
    { TidyAttr_DRAGGABLE,               "draggable",               CH_PCDATA   },
    { TidyAttr_DROPZONE,                "dropzone",                CH_PCDATA   },
    { TidyAttr_FORM,                    "form",                    CH_PCDATA   },
    { TidyAttr_FORMACTION,              "formaction",              CH_PCDATA   },
    { TidyAttr_FORMENCTYPE,             "formenctype",             CH_PCDATA   },
    { TidyAttr_FORMMETHOD,              "formmethod",              CH_PCDATA   },
    { TidyAttr_FORMNOVALIDATE,          "formnovalidate",          CH_PCDATA   },
    { TidyAttr_FORMTARGET,              "formtarget",              CH_PCDATA   },
    { TidyAttr_HIDDEN,                  "hidden",                  CH_PCDATA   },
    { TidyAttr_HIGH,                    "high",                    CH_PCDATA   },
    { TidyAttr_ICON,                    "icon",                    CH_PCDATA   },
    { TidyAttr_KEYTYPE,                 "keytype",                 CH_PCDATA   },
    { TidyAttr_KIND,                    "kind",                    CH_PCDATA   },
    { TidyAttr_LIST,                    "list",                    CH_PCDATA   },
    { TidyAttr_LOOP,                    "loop",                    CH_PCDATA   },
    { TidyAttr_LOW,                     "low",                     CH_PCDATA   },
    { TidyAttr_MANIFEST,                "manifest",                CH_PCDATA   },
    { TidyAttr_MAX,                     "max",                     CH_PCDATA   },
    { TidyAttr_MEDIAGROUP,              "mediagroup",              CH_PCDATA   },
    { TidyAttr_MIN,                     "min",                     CH_PCDATA   },
    { TidyAttr_NOVALIDATE,              "novalidate",              CH_PCDATA   },
    { TidyAttr_OPEN,                    "open",                    CH_BOOL     }, /* Is. #925 PR #932 */
    { TidyAttr_OPTIMUM,                 "optimum",                 CH_PCDATA   },
    { TidyAttr_OnABORT,                 "onabort",                 CH_PCDATA   },
    { TidyAttr_OnAFTERPRINT,            "onafterprint",            CH_PCDATA   },
    { TidyAttr_OnBEFOREPRINT,           "onbeforeprint",           CH_PCDATA   },
    { TidyAttr_OnCANPLAY,               "oncanplay",               CH_PCDATA   },
    { TidyAttr_OnCANPLAYTHROUGH,        "oncanplaythrough",        CH_PCDATA   },
    { TidyAttr_OnCONTEXTMENU,           "oncontextmenu",           CH_PCDATA   },
    { TidyAttr_OnCUECHANGE,             "oncuechange",             CH_PCDATA   },
    { TidyAttr_OnDRAG,                  "ondrag",                  CH_PCDATA   },
    { TidyAttr_OnDRAGEND,               "ondragend",               CH_PCDATA   },
    { TidyAttr_OnDRAGENTER,             "ondragenter",             CH_PCDATA   },
    { TidyAttr_OnDRAGLEAVE,             "ondragleave",             CH_PCDATA   },
    { TidyAttr_OnDRAGOVER,              "ondragover",              CH_PCDATA   },
    { TidyAttr_OnDRAGSTART,             "ondragstart",             CH_PCDATA   },
    { TidyAttr_OnDROP,                  "ondrop",                  CH_PCDATA   },
    { TidyAttr_OnDURATIONCHANGE,        "ondurationchange",        CH_PCDATA   },
    { TidyAttr_OnEMPTIED,               "onemptied",               CH_PCDATA   },
    { TidyAttr_OnENDED,                 "onended",                 CH_PCDATA   },
    { TidyAttr_OnERROR,                 "onerror",                 CH_PCDATA   },
    { TidyAttr_OnHASHCHANGE,            "onhashchange",            CH_PCDATA   },
    { TidyAttr_OnINPUT,                 "oninput",                 CH_PCDATA   },
    { TidyAttr_OnINVALID,               "oninvalid",               CH_PCDATA   },
    { TidyAttr_OnLOADEDDATA,            "onloadeddata",            CH_PCDATA   },
    { TidyAttr_OnLOADEDMETADATA,        "onloadedmetadata",        CH_PCDATA   },
    { TidyAttr_OnLOADSTART,             "onloadstart",             CH_PCDATA   },
    { TidyAttr_OnMESSAGE,               "onmessage",               CH_PCDATA   },
    { TidyAttr_OnMOUSEWHEEL,            "onmousewheel",            CH_PCDATA   },
    { TidyAttr_OnOFFLINE,               "onoffline",               CH_PCDATA   },
    { TidyAttr_OnONLINE,                "ononline",                CH_PCDATA   },
    { TidyAttr_OnPAGEHIDE,              "onpagehide",              CH_PCDATA   },
    { TidyAttr_OnPAGESHOW,              "onpageshow",              CH_PCDATA   },
    { TidyAttr_OnPAUSE,                 "onpause",                 CH_PCDATA   },
    { TidyAttr_OnPLAY,                  "onplay",                  CH_PCDATA   },
    { TidyAttr_OnPLAYING,               "onplaying",               CH_PCDATA   },
    { TidyAttr_OnPOPSTATE,              "onpopstate",              CH_PCDATA   },
    { TidyAttr_OnPROGRESS,              "onprogress",              CH_PCDATA   },
    { TidyAttr_OnRATECHANGE,            "onratechange",            CH_PCDATA   },
    { TidyAttr_OnREADYSTATECHANGE,      "onreadystatechange",      CH_PCDATA   },
    { TidyAttr_OnREDO,                  "onredo",                  CH_PCDATA   },
    { TidyAttr_OnRESIZE,                "onresize",                CH_PCDATA   },
    { TidyAttr_OnSCROLL,                "onscroll",                CH_PCDATA   },
    { TidyAttr_OnSEEKED,                "onseeked",                CH_PCDATA   },
    { TidyAttr_OnSEEKING,               "onseeking",               CH_PCDATA   },
    { TidyAttr_OnSHOW,                  "onshow",                  CH_PCDATA   },
    { TidyAttr_OnSTALLED,               "onstalled",               CH_PCDATA   },
    { TidyAttr_OnSTORAGE,               "onstorage",               CH_PCDATA   },
    { TidyAttr_OnSUSPEND,               "onsuspend",               CH_PCDATA   },
    { TidyAttr_OnTIMEUPDATE,            "ontimeupdate",            CH_PCDATA   },
    { TidyAttr_OnUNDO,                  "onundo",                  CH_PCDATA   },
    { TidyAttr_OnVOLUMECHANGE,          "onvolumechange",          CH_PCDATA   },
    { TidyAttr_OnWAITING,               "onwaiting",               CH_PCDATA   },
    { TidyAttr_PATTERN,                 "pattern",                 CH_PCDATA   },
    { TidyAttr_PLACEHOLDER,             "placeholder",             CH_PCDATA   },
    { TidyAttr_POSTER,                  "poster",                  CH_PCDATA   },
    { TidyAttr_PRELOAD,                 "preload",                 CH_PCDATA   },
    { TidyAttr_PUBDATE,                 "pubdate",                 CH_PCDATA   },
    { TidyAttr_RADIOGROUP,              "radiogroup",              CH_PCDATA   },
    { TidyAttr_REQUIRED,                "required",                CH_PCDATA   },
    { TidyAttr_REVERSED,                "reversed",                CH_PCDATA   },
    { TidyAttr_SANDBOX,                 "sandbox",                 CH_PCDATA   },
    { TidyAttr_SCOPED,                  "scoped",                  CH_PCDATA   },
    { TidyAttr_SEAMLESS,                "seamless",                CH_PCDATA   },
    { TidyAttr_SIZES,                   "sizes",                   CH_PCDATA   },
    { TidyAttr_SPELLCHECK,              "spellcheck",              CH_PCDATA   },
    { TidyAttr_SRCDOC,                  "srcdoc",                  CH_PCDATA   },
    { TidyAttr_SRCLANG,                 "srclang",                 CH_PCDATA   },
    { TidyAttr_STEP,                    "step",                    CH_PCDATA   },
  
    /* HTML5 Aria Attributes */
    { TidyAttr_ARIA_ACTIVEDESCENDANT,   "aria-activedescendant",   CH_PCDATA   },
    { TidyAttr_ARIA_ATOMIC,             "aria-atomic",             CH_PCDATA   },
    { TidyAttr_ARIA_AUTOCOMPLETE,       "aria-autocomplete",       CH_PCDATA   },
    { TidyAttr_ARIA_BUSY,               "aria-busy",               CH_PCDATA   },
    { TidyAttr_ARIA_CHECKED,            "aria-checked",            CH_PCDATA   },
    { TidyAttr_ARIA_CONTROLS,           "aria-controls",           CH_PCDATA   },
    { TidyAttr_ARIA_DESCRIBEDBY,        "aria-describedby",        CH_PCDATA   },
    { TidyAttr_ARIA_DISABLED,           "aria-disabled",           CH_PCDATA   },
    { TidyAttr_ARIA_DROPEFFECT,         "aria-dropeffect",         CH_PCDATA   },
    { TidyAttr_ARIA_EXPANDED,           "aria-expanded",           CH_PCDATA   },
    { TidyAttr_ARIA_FLOWTO,             "aria-flowto",             CH_PCDATA   },
    { TidyAttr_ARIA_GRABBED,            "aria-grabbed",            CH_PCDATA   },
    { TidyAttr_ARIA_HASPOPUP,           "aria-haspopup",           CH_PCDATA   },
    { TidyAttr_ARIA_HIDDEN,             "aria-hidden",             CH_PCDATA   },
    { TidyAttr_ARIA_INVALID,            "aria-invalid",            CH_PCDATA   },
    { TidyAttr_ARIA_LABEL,              "aria-label",              CH_PCDATA   },
    { TidyAttr_ARIA_LABELLEDBY,         "aria-labelledby",         CH_PCDATA   },
    { TidyAttr_ARIA_LEVEL,              "aria-level",              CH_PCDATA   },
    { TidyAttr_ARIA_LIVE,               "aria-live",               CH_PCDATA   },
    { TidyAttr_ARIA_MULTILINE,          "aria-multiline",          CH_PCDATA   },
    { TidyAttr_ARIA_MULTISELECTABLE,    "aria-multiselectable",    CH_PCDATA   },
    { TidyAttr_ARIA_ORIENTATION,        "aria-orientation",        CH_PCDATA   },
    { TidyAttr_ARIA_OWNS,               "aria-owns",               CH_PCDATA   },
    { TidyAttr_ARIA_POSINSET,           "aria-posinset",           CH_PCDATA   },
    { TidyAttr_ARIA_PRESSED,            "aria-pressed",            CH_PCDATA   },
    { TidyAttr_ARIA_READONLY,           "aria-readonly",           CH_PCDATA   },
    { TidyAttr_ARIA_RELEVANT,           "aria-relevant",           CH_PCDATA   },
    { TidyAttr_ARIA_REQUIRED,           "aria-required",           CH_PCDATA   },
    { TidyAttr_ARIA_SELECTED,           "aria-selected",           CH_PCDATA   },
    { TidyAttr_ARIA_SETSIZE,            "aria-setsize",            CH_PCDATA   },
    { TidyAttr_ARIA_SORT,               "aria-sort",               CH_PCDATA   },
    { TidyAttr_ARIA_VALUEMAX,           "aria-valuemax",           CH_PCDATA   },
    { TidyAttr_ARIA_VALUEMIN,           "aria-valuemin",           CH_PCDATA   },
    { TidyAttr_ARIA_VALUENOW,           "aria-valuenow",           CH_PCDATA   },
    { TidyAttr_ARIA_VALUETEXT,          "aria-valuetext",          CH_PCDATA   },
    { TidyAttr_X,                       "x",                       CH_PCDATA    }, /* for <svg> */
    { TidyAttr_Y,                       "y",                       CH_PCDATA    }, /* for <svg> */
    { TidyAttr_VIEWBOX,                  "viewbox",                CH_PCDATA    }, /* for <svg> */
    { TidyAttr_PRESERVEASPECTRATIO,      "preserveaspectratio",    CH_PCDATA    }, /* for <svg> */
    { TidyAttr_ZOOMANDPAN,               "zoomandpan",             CH_PCDATA    }, /* for <svg> */
    { TidyAttr_BASEPROFILE,              "baseprofile",            CH_PCDATA    }, /* for <svg> */
    { TidyAttr_CONTENTSCRIPTTYPE,        "contentscripttype",      CH_PCDATA    }, /* for <svg> */
    { TidyAttr_CONTENTSTYLETYPE,         "contentstyletype",       CH_PCDATA    }, /* for <svg> */
    { TidyAttr_DISPLAY,                  "display",                CH_PCDATA   }, /* on MATH tag (html5) */
  
    /* RDFa Attributes */
    { TidyAttr_ABOUT,                    "about",                  CH_RDFASCURIE },
    { TidyAttr_DATATYPE,                 "datatype",               CH_RDFATERM   },
    { TidyAttr_INLIST,                   "inlist",                 CH_BOOL       },
    { TidyAttr_PREFIX,                   "prefix",                 CH_RDFAPREFIX },
    { TidyAttr_PROPERTY,                 "property",               CH_RDFATERMS  },
    { TidyAttr_RESOURCE,                 "resource",               CH_RDFASCURIE },
    { TidyAttr_TYPEOF,                   "typeof",                 CH_RDFATERMS  },
    { TidyAttr_VOCAB,                    "vocab",                  CH_URL        },
  
    { TidyAttr_INTEGRITY,                "integrity",              CH_PCDATA   },
  
    /* Preload spec: https://www.w3.org/TR/preload/ */
    { TidyAttr_AS,                       "as",                     CH_PCDATA   },
  
    /* for xmlns:xlink in <svg> */
    { TidyAttr_XMLNSXLINK,                "xmlns:xlink",           CH_URL       },
    { TidyAttr_SLOT,                      "slot",                  CH_PCDATA    },
    { TidyAttr_LOADING,                   "loading",               CH_LOADING   }, /* IMG, IFRAME */
  
    /* SVG paint attributes (SVG 1.1) */
    { TidyAttr_FILL,                     "fill",                  CH_SVG        },
    { TidyAttr_FILLRULE,                 "fill-rule",             CH_SVG        },
    { TidyAttr_STROKE,                   "stroke",                CH_SVG        },
    { TidyAttr_STROKEDASHARRAY,          "stroke-dasharray",      CH_SVG        },
    { TidyAttr_STROKEDASHOFFSET,         "stroke-dashoffset",     CH_SVG        },
    { TidyAttr_STROKELINECAP,            "stroke-linecap",        CH_SVG        },
    { TidyAttr_STROKELINEJOIN,           "stroke-linejoin",       CH_SVG        },
    { TidyAttr_STROKEMITERLIMIT,         "stroke-miterlimit",     CH_SVG        },
    { TidyAttr_STROKEWIDTH,              "stroke-width",          CH_SVG        },
    { TidyAttr_COLORINTERPOLATION,       "color-interpolation",   CH_SVG        },
    { TidyAttr_COLORRENDERING,           "color-rendering",       CH_SVG        },
    { TidyAttr_OPACITY,                  "opacity",               CH_SVG        },
    { TidyAttr_STROKEOPACITY,            "stroke-opacity",        CH_SVG        },
    { TidyAttr_FILLOPACITY,              "fill-opacity",          CH_SVG        },
  
    /* this must be the final entry */
    { N_TIDY_ATTRIBS,                    NULL,                     NULL         }
  };
  
  static uint AttributeVersions(Node* node, AttVal* attval)
  {
      uint i;
  
      /* Override or add to items in attrdict.c */
      if (attval && attval->attribute) {
          /* HTML5 data-* attributes can't be added generically; handle here. */
          if (TY_(tmbstrncmp)(attval->attribute, "data-", 5) == 0)
              return (XH50 | HT50);
      }
      /* TODO: maybe this should return VERS_PROPRIETARY instead? */
      if (!attval || !attval->dict)
          return VERS_UNKNOWN;
  
      if (!(!node || !node->tag || !node->tag->attrvers))
          for (i = 0; node->tag->attrvers[i].attribute; ++i)
              if (node->tag->attrvers[i].attribute == attval->dict->id)
                  return node->tag->attrvers[i].versions;
  
      return VERS_PROPRIETARY;
  }
  
  
  /* return the version of the attribute "id" of element "node" */
  uint TY_(NodeAttributeVersions)( Node* node, TidyAttrId id )
  {
      uint i;
  
      if (!node || !node->tag || !node->tag->attrvers)
          return VERS_UNKNOWN;
  
      for (i = 0; node->tag->attrvers[i].attribute; ++i)
          if (node->tag->attrvers[i].attribute == id)
              return node->tag->attrvers[i].versions;
  
      return VERS_UNKNOWN;
  }
  
  /* returns true if the element is a W3C defined element
   * but the element/attribute combination is not. We're
   * only defining as "proprietary" items that are not in
   * the element's AttrVersion structure.
   */
  Bool TY_(AttributeIsProprietary)(Node* node, AttVal* attval)
  {
      if (!node || !attval)
          return no;
  
      if (!node->tag)
          return no;
  
      if (!(node->tag->versions & VERS_ALL))
          return no;
  
      if (AttributeVersions(node, attval) & VERS_ALL)
          return no;
  
      return yes;
  }
  
  /* returns true if the element is a W3C defined element
   * but the element/attribute combination is not. We're
   * considering it a mismatch if the document version
   * does not allow the attribute as called out in its
   * AttrVersion structure.
   */
  Bool TY_(AttributeIsMismatched)(Node* node, AttVal* attval, TidyDocImpl* doc)
  {
      uint doctype;
      
      if (!node || !attval)
          return no;
      
      if (!node->tag)
          return no;
      
      if (!(node->tag->versions & VERS_ALL))
          return no;
  
      doctype = doc->lexer->versionEmitted == 0 ? doc->lexer->doctype : doc->lexer->versionEmitted;
  
      if (AttributeVersions(node, attval) & doctype)
          return no;
      
      return yes;
  }
  
  
  /* used by CheckColor() */
  struct _colors
  {
      ctmbstr name;
      ctmbstr hex;
  };
  
  static const struct _colors colors[] =
  {
      { "black",   "#000000" },
      { "green",   "#008000" },
      { "silver",  "#C0C0C0" },
      { "lime",    "#00FF00" },
      { "gray",    "#808080" },
      { "olive",   "#808000" },
      { "white",   "#FFFFFF" },
      { "yellow",  "#FFFF00" },
      { "maroon",  "#800000" },
      { "navy",    "#000080" },
      { "red",     "#FF0000" },
      { "blue",    "#0000FF" },
      { "purple",  "#800080" },
      { "teal",    "#008080" },
      { "fuchsia", "#FF00FF" },
      { "aqua",    "#00FFFF" },
      { NULL,      NULL      }
  };
  
  static const struct _colors extended_colors[] =
  {
      { "aliceblue", "#f0f8ff" },
      { "antiquewhite", "#faebd7" },
      { "aquamarine", "#7fffd4" },
      { "azure", "#f0ffff" },
      { "beige", "#f5f5dc" },
      { "bisque", "#ffe4c4" },
      { "blanchedalmond", "#ffebcd" },
      { "blueviolet", "#8a2be2" },
      { "brown", "#a52a2a" },
      { "burlywood", "#deb887" },
      { "cadetblue", "#5f9ea0" },
      { "chartreuse", "#7fff00" },
      { "chocolate", "#d2691e" },
      { "coral", "#ff7f50" },
      { "cornflowerblue", "#6495ed" },
      { "cornsilk", "#fff8dc" },
      { "crimson", "#dc143c" },
      { "cyan", "#00ffff" },
      { "darkblue", "#00008b" },
      { "darkcyan", "#008b8b" },
      { "darkgoldenrod", "#b8860b" },
      { "darkgray", "#a9a9a9" },
      { "darkgreen", "#006400" },
      { "darkgrey", "#a9a9a9" },
      { "darkkhaki", "#bdb76b" },
      { "darkmagenta", "#8b008b" },
      { "darkolivegreen", "#556b2f" },
      { "darkorange", "#ff8c00" },
      { "darkorchid", "#9932cc" },
      { "darkred", "#8b0000" },
      { "darksalmon", "#e9967a" },
      { "darkseagreen", "#8fbc8f" },
      { "darkslateblue", "#483d8b" },
      { "darkslategray", "#2f4f4f" },
      { "darkslategrey", "#2f4f4f" },
      { "darkturquoise", "#00ced1" },
      { "darkviolet", "#9400d3" },
      { "deeppink", "#ff1493" },
      { "deepskyblue", "#00bfff" },
      { "dimgray", "#696969" },
      { "dimgrey", "#696969" },
      { "dodgerblue", "#1e90ff" },
      { "firebrick", "#b22222" },
      { "floralwhite", "#fffaf0" },
      { "forestgreen", "#228b22" },
      { "gainsboro", "#dcdcdc" },
      { "ghostwhite", "#f8f8ff" },
      { "gold", "#ffd700" },
      { "goldenrod", "#daa520" },
      { "greenyellow", "#adff2f" },
      { "grey", "#808080" },
      { "honeydew", "#f0fff0" },
      { "hotpink", "#ff69b4" },
      { "indianred", "#cd5c5c" },
      { "indigo", "#4b0082" },
      { "ivory", "#fffff0" },
      { "khaki", "#f0e68c" },
      { "lavender", "#e6e6fa" },
      { "lavenderblush", "#fff0f5" },
      { "lawngreen", "#7cfc00" },
      { "lemonchiffon", "#fffacd" },
      { "lightblue", "#add8e6" },
      { "lightcoral", "#f08080" },
      { "lightcyan", "#e0ffff" },
      { "lightgoldenrodyellow", "#fafad2" },
      { "lightgray", "#d3d3d3" },
      { "lightgreen", "#90ee90" },
      { "lightgrey", "#d3d3d3" },
      { "lightpink", "#ffb6c1" },
      { "lightsalmon", "#ffa07a" },
      { "lightseagreen", "#20b2aa" },
      { "lightskyblue", "#87cefa" },
      { "lightslategray", "#778899" },
      { "lightslategrey", "#778899" },
      { "lightsteelblue", "#b0c4de" },
      { "lightyellow", "#ffffe0" },
      { "limegreen", "#32cd32" },
      { "linen", "#faf0e6" },
      { "magenta", "#ff00ff" },
      { "mediumaquamarine", "#66cdaa" },
      { "mediumblue", "#0000cd" },
      { "mediumorchid", "#ba55d3" },
      { "mediumpurple", "#9370db" },
      { "mediumseagreen", "#3cb371" },
      { "mediumslateblue", "#7b68ee" },
      { "mediumspringgreen", "#00fa9a" },
      { "mediumturquoise", "#48d1cc" },
      { "mediumvioletred", "#c71585" },
      { "midnightblue", "#191970" },
      { "mintcream", "#f5fffa" },
      { "mistyrose", "#ffe4e1" },
      { "moccasin", "#ffe4b5" },
      { "navajowhite", "#ffdead" },
      { "oldlace", "#fdf5e6" },
      { "olivedrab", "#6b8e23" },
      { "orange", "#ffa500" },
      { "orangered", "#ff4500" },
      { "orchid", "#da70d6" },
      { "palegoldenrod", "#eee8aa" },
      { "palegreen", "#98fb98" },
      { "paleturquoise", "#afeeee" },
      { "palevioletred", "#db7093" },
      { "papayawhip", "#ffefd5" },
      { "peachpuff", "#ffdab9" },
      { "peru", "#cd853f" },
      { "pink", "#ffc0cb" },
      { "plum", "#dda0dd" },
      { "powderblue", "#b0e0e6" },
      { "rebeccapurple", "#663399" },
      { "rosybrown", "#bc8f8f" },
      { "royalblue", "#4169e1" },
      { "saddlebrown", "#8b4513" },
      { "salmon", "#fa8072" },
      { "sandybrown", "#f4a460" },
      { "seagreen", "#2e8b57" },
      { "seashell", "#fff5ee" },
      { "sienna", "#a0522d" },
      { "skyblue", "#87ceeb" },
      { "slateblue", "#6a5acd" },
      { "slategray", "#708090" },
      { "slategrey", "#708090" },
      { "snow", "#fffafa" },
      { "springgreen", "#00ff7f" },
      { "steelblue", "#4682b4" },
      { "tan", "#d2b48c" },
      { "thistle", "#d8bfd8" },
      { "tomato", "#ff6347" },
      { "turquoise", "#40e0d0" },
      { "violet", "#ee82ee" },
      { "wheat", "#f5deb3" },
      { "whitesmoke", "#f5f5f5" },
      { "yellowgreen", "#9acd32" },
      { NULL, NULL }
  };
  
  static ctmbstr GetColorCode(ctmbstr name, Bool use_css_colors)
  {
      uint i;
  
      for (i = 0; colors[i].name; ++i)
          if (TY_(tmbstrcasecmp)(name, colors[i].name) == 0)
              return colors[i].hex;
  
      if (use_css_colors)
          for (i = 0; extended_colors[i].name; ++i)
              if (TY_(tmbstrcasecmp)(name, extended_colors[i].name) == 0)
                  return extended_colors[i].hex;
  
      return NULL;
  }
  
  static ctmbstr GetColorName(ctmbstr code, Bool use_css_colors)
  {
      uint i;
  
      for (i = 0; colors[i].name; ++i)
          if (TY_(tmbstrcasecmp)(code, colors[i].hex) == 0)
              return colors[i].name;
  
      if (use_css_colors)
          for (i = 0; extended_colors[i].name; ++i)
              if (TY_(tmbstrcasecmp)(code, extended_colors[i].hex) == 0)
                  return extended_colors[i].name;
  
      return NULL;
  }
  
  static uint attrsHash(ctmbstr s)
  {
      uint hashval;
  
      for (hashval = 0; *s != '\0'; s++)
          hashval = *s + 31*hashval;
  
      return hashval % ATTRIBUTE_HASH_SIZE;
  }
  
  static const Attribute *attrsInstall(TidyDocImpl* doc, TidyAttribImpl * attribs,
                                  const Attribute* old)
  {
      AttrHash *np;
      uint hashval;
  
      if (old)
      {
          np = (AttrHash *)TidyDocAlloc(doc, sizeof(*np));
          np->attr = old;
  
          hashval = attrsHash(old->name);
          np->next = attribs->hashtab[hashval];
          attribs->hashtab[hashval] = np;
      }
  
      return old;
  }
  
  static void attrsRemoveFromHash( TidyDocImpl* doc, TidyAttribImpl *attribs,
                              ctmbstr s )
  {
      uint h = attrsHash(s);
      AttrHash *p, *prev = NULL;
      for (p = attribs->hashtab[h]; p && p->attr; p = p->next)
      {
          if (TY_(tmbstrcmp)(s, p->attr->name) == 0)
          {
              AttrHash* next = p->next;
              if ( prev )
                  prev->next = next; 
              else
                  attribs->hashtab[h] = next;
              TidyDocFree(doc, p);
              return;
          }
          prev = p;
      }
  }
  
  static void attrsEmptyHash( TidyDocImpl* doc, TidyAttribImpl * attribs )
  {
      AttrHash *dict, *next;
      uint i;
  
      for (i = 0; i < ATTRIBUTE_HASH_SIZE; ++i)
      {
          dict = attribs->hashtab[i];
  
          while(dict)
          {
              next = dict->next;
              TidyDocFree(doc, dict);
              dict = next;
          }
  
          attribs->hashtab[i] = NULL;
      }
  }
  
  static const Attribute* attrsLookup(TidyDocImpl* doc,
                                 TidyAttribImpl* ARG_UNUSED(attribs),
                                 ctmbstr atnam)
  {
      const Attribute *np;
      const AttrHash *p;
  
      if (!atnam)
          return NULL;
  
      for (p = attribs->hashtab[attrsHash(atnam)]; p && p->attr; p = p->next)
          if (TY_(tmbstrcasecmp)(atnam, p->attr->name) == 0)
              return p->attr;
  
      for (np = attribute_defs; np && np->name; ++np)
          if (TY_(tmbstrcasecmp)(atnam, np->name) == 0)
              return attrsInstall(doc, attribs, np);
  
      return NULL;
  }
  
  
  /* Locate attributes by type */
  AttVal* TY_(AttrGetById)( Node* node, TidyAttrId id )
  {
     AttVal* av;
     for ( av = node->attributes; av; av = av->next )
     {
       if ( AttrIsId(av, id) )
           return av;
     }
     return NULL;
  }
  
  /* public method for finding attribute definition by name */
  const Attribute* TY_(FindAttribute)( TidyDocImpl* doc, AttVal *attval )
  {
      if ( attval )
         return attrsLookup( doc, &doc->attribs, attval->attribute );
      return NULL;
  }
  
  AttVal* TY_(GetAttrByName)( Node *node, ctmbstr name )
  {
      AttVal *attr;
      for (attr = node->attributes; attr != NULL; attr = attr->next)
      {
          if (attr->attribute && TY_(tmbstrcmp)(attr->attribute, name) == 0)
              break;
      }
      return attr;
  }
  
  void TY_(DropAttrByName)( TidyDocImpl* doc, Node *node, ctmbstr name )
  {
      AttVal *attr, *prev = NULL, *next;
  
      for (attr = node->attributes; attr != NULL; prev = attr, attr = next)
      {
          next = attr->next;
  
          if (attr->attribute && TY_(tmbstrcmp)(attr->attribute, name) == 0)
          {
              if (prev)
                   prev->next = next;
              else
                   node->attributes = next;
  
              TY_(FreeAttribute)( doc, attr ); 
              break;
          }
      }
  }
  
  AttVal* TY_(AddAttribute)( TidyDocImpl* doc,
                             Node *node, ctmbstr name, ctmbstr value )
  {
      AttVal *av = TY_(NewAttribute)(doc);
      av->delim = '"';
      av->attribute = TY_(tmbstrdup)(doc->allocator, name);
  
      if (value)
          av->value = TY_(tmbstrdup)(doc->allocator, value);
      else
          av->value = NULL;
  
      av->dict = attrsLookup(doc, &doc->attribs, name);
  
      TY_(InsertAttributeAtEnd)(node, av);
      return av;
  }
  
  AttVal* TY_(RepairAttrValue)(TidyDocImpl* doc, Node* node, ctmbstr name, ctmbstr value)
  {
      AttVal* old = TY_(GetAttrByName)(node, name);
  
      if (old)
      {
          if (old->value)
              TidyDocFree(doc, old->value);
          if (value)
              old->value = TY_(tmbstrdup)(doc->allocator, value);
          else
              old->value = NULL;
  
          return old;
      }
      else
          return TY_(AddAttribute)(doc, node, name, value);
  }
  
  
  void TY_(FreeAttrPriorityList)( TidyDocImpl* doc )
  {
      PriorityAttribs *priorities = &(doc->attribs.priorityAttribs);
  
      if ( priorities->list )
      {
          uint i = 0;
          while ( priorities->list[i] != NULL )
          {
              TidyFree( doc->allocator, priorities->list[i] );
              i++;
          }
  
          TidyFree( doc->allocator, priorities->list );
      }
  }
  
  
  void TY_(DefinePriorityAttribute)(TidyDocImpl* doc, ctmbstr name)
  {
      enum { capacity = 10 };
      PriorityAttribs *priorities = &(doc->attribs.priorityAttribs);
  
      if ( !priorities->list )
      {
          priorities->list = TidyAlloc(doc->allocator, sizeof(ctmbstr) * capacity );
          priorities->list[0] = NULL;
          priorities->capacity = capacity;
          priorities->count = 0;
      }
  
      if ( priorities->count >= priorities->capacity )
      {
          priorities->capacity = priorities->capacity * 2;
          priorities->list = TidyRealloc(doc->allocator, priorities->list, sizeof(tmbstr) * priorities->capacity + 1 );
      }
  
      priorities->list[priorities->count] = TY_(tmbstrdup)( doc->allocator, name);
      priorities->count++;
      priorities->list[priorities->count] = NULL;
  }
  
  
  TidyIterator TY_(getPriorityAttrList)( TidyDocImpl* doc )
  {
      PriorityAttribs *priorities = &(doc->attribs.priorityAttribs);
      size_t result = priorities->count > 0 ? 1 : 0;
  
      return (TidyIterator) result;
  }
  
  
  ctmbstr  TY_(getNextPriorityAttr)( TidyDocImpl* doc, TidyIterator* iter )
  {
      PriorityAttribs *priorities = &(doc->attribs.priorityAttribs);
      size_t index;
      ctmbstr result = NULL;
      assert( iter != NULL );
      index = (size_t)*iter;
  
      if ( index > 0 && index <= priorities->count )
      {
          result = priorities->list[index-1];
          index++;
      }
      *iter = (TidyIterator) ( index <= priorities->count ? index : (size_t)0 );
  
      return result;
  }
  
  
  static Bool CheckAttrType( TidyDocImpl* doc,
                             ctmbstr attrname, AttrCheck type )
  {
      const Attribute* np = attrsLookup( doc, &doc->attribs, attrname );
      return (Bool)( np && np->attrchk == type );
  }
  
  Bool TY_(IsUrl)( TidyDocImpl* doc, ctmbstr attrname )
  {
      return CheckAttrType( doc, attrname, CH_URL );
  }
  
  /*
  Bool IsBool( TidyDocImpl* doc, ctmbstr attrname )
  {
      return CheckAttrType( doc, attrname, CH_BOOL );
  }
  */
  
  Bool TY_(IsScript)( TidyDocImpl* doc, ctmbstr attrname )
  {
      return CheckAttrType( doc, attrname, CH_SCRIPT );
  }
  
  /* may id or name serve as anchor? */
  Bool TY_(IsAnchorElement)( TidyDocImpl* ARG_UNUSED(doc), Node* node)
  {
      TidyTagId tid = TagId( node );
      if ( tid == TidyTag_A      ||
           tid == TidyTag_APPLET ||
           tid == TidyTag_FORM   ||
           tid == TidyTag_FRAME  ||
           tid == TidyTag_IFRAME ||
           tid == TidyTag_IMG    ||
           tid == TidyTag_MAP )
          return yes;
  
      return no;
  }
  
  /*
    In CSS1, selectors can contain only the characters A-Z, 0-9,
    and Unicode characters 161-255, plus dash (-); they cannot start
    with a dash or a digit; they can also contain escaped characters
    and any Unicode character as a numeric code (see next item).
  
    The backslash followed by at most four hexadecimal digits
    (0..9A..F) stands for the Unicode character with that number.
  
    Any character except a hexadecimal digit can be escaped to remove
    its special meaning, by putting a backslash in front.
  
    #508936 - CSS class naming for -clean option
  */
  Bool TY_(IsCSS1Selector)( ctmbstr buf )
  {
      Bool valid = yes;
      int esclen = 0;
      byte c;
      int pos;
  
      for ( pos=0; valid && (c = *buf++); ++pos )
      {
          if ( c == '\\' )
          {
              esclen = 1;  /* ab\555\444 is 4 chars {'a', 'b', \555, \444} */
          }
          else if ( isdigit( c ) )
          {
              /* Digit not 1st, unless escaped (Max length "\112F") */
              if ( esclen > 0 )
                  valid = ( ++esclen < 6 );
              if ( valid )
                  valid = ( pos>0 || esclen>0 );
          }
          else
          {
              valid = (
                  esclen > 0                       /* Escaped? Anything goes. */
                  || ( pos>0 && c == '-' )         /* Dash cannot be 1st char */
                  || isalpha(c)                    /* a-z, A-Z anywhere */
                  || ( c >= 161 )                  /* Unicode 161-255 anywhere */
              );
              esclen = 0;
          }
      }
      return valid;
  }
  
  /* free single anchor */
  static void FreeAnchor(TidyDocImpl* doc, Anchor *a)
  {
      if ( a )
          TidyDocFree( doc, a->name );
      TidyDocFree( doc, a );
  }
  
  static uint anchorNameHash(ctmbstr s)
  {
      uint hashval = 0;
      /* Issue #149 - an inferred name can be null. avoid crash */
      if (s) 
      {
          for ( ; *s != '\0'; s++) {
              tmbchar c = TY_(ToLower)( *s );
              hashval = c + 31*hashval;
          }
      }
      return hashval % ANCHOR_HASH_SIZE;
  }
  
  /*\
   *  New Service for HTML5
   *  Issue #185 - Treat elements ids as case-sensitive
   *  if in HTML5 modes, make hash of value AS IS!
  \*/
  static uint anchorNameHash5(ctmbstr s)
  {
      uint hashval = 0;
      /* Issue #149 - an inferred name can be null. avoid crash */
      if (s) 
      {
          for ( ; *s != '\0'; s++) {
              tmbchar c = *s;
              hashval = c + 31*hashval;
          }
      }
      return hashval % ANCHOR_HASH_SIZE;
  }
  
  
  /*\ 
   *  removes anchor for specific node 
   *  Issue #185 - Treat elements ids as case-sensitive
   *  if in HTML5 modes, make hash of value AS IS!
  \*/
  void TY_(RemoveAnchorByNode)( TidyDocImpl* doc, ctmbstr name, Node *node )
  {
      TidyAttribImpl* attribs = &doc->attribs;
      Anchor *delme = NULL, *curr, *prev = NULL;
      uint h;
      if (TY_(HTMLVersion)(doc) == HT50)
          h = anchorNameHash5(name);
      else
          h = anchorNameHash(name);
  
      for ( curr=attribs->anchor_hash[h]; curr!=NULL; curr=curr->next )
      {
          if ( curr->node == node )
          {
              if ( prev )
                  prev->next = curr->next;
              else
                  attribs->anchor_hash[h] = curr->next;
              delme = curr;
              break;
          }
          prev = curr;
      }
      FreeAnchor( doc, delme );
  }
  
  /* initialize new anchor 
     Is. #726 & #185 - HTML5 is case-sensitive
  */
  static Anchor* NewAnchor( TidyDocImpl* doc, ctmbstr name, Node* node )
  {
      Anchor *a = (Anchor*) TidyDocAlloc( doc, sizeof(Anchor) );
  
      a->name = TY_(tmbstrdup)( doc->allocator, name );
      if (!TY_(IsHTML5Mode)(doc)) /* Is. #726 - if NOT HTML5, to lowercase */
          a->name = TY_(tmbstrtolower)(a->name);
      a->node = node;
      a->next = NULL;
  
      return a;
  }
  
  /*\
   *  add new anchor to namespace 
   *  Issue #185 - Treat elements ids as case-sensitive
   *  if in HTML5 modes, make hash of value AS IS!
  \*/
  static Anchor* AddAnchor( TidyDocImpl* doc, ctmbstr name, Node *node )
  {
      TidyAttribImpl* attribs = &doc->attribs;
      Anchor *a = NewAnchor( doc, name, node );
      uint h;
      if (TY_(HTMLVersion)(doc) == HT50)
          h = anchorNameHash5(name);
      else
          h = anchorNameHash(name);
  
      if ( attribs->anchor_hash[h] == NULL)
           attribs->anchor_hash[h] = a;
      else
      {
          Anchor *here =  attribs->anchor_hash[h];
          while (here->next)
              here = here->next;
          here->next = a;
      }
  
      return attribs->anchor_hash[h];
  }
  
  /*\
   *  return node associated with anchor 
   *  Issue #185 - Treat elements ids as case-sensitive
   *  if in HTML5 modes, make hash of value AS IS!
  \*/
  static Node* GetNodeByAnchor( TidyDocImpl* doc, ctmbstr name )
  {
      TidyAttribImpl* attribs = &doc->attribs;
      Anchor *found;
      uint h;
      tmbstr lname = TY_(tmbstrdup)(doc->allocator, name);
      if (TY_(HTMLVersion)(doc) == HT50) {
          h = anchorNameHash5(name);
      }
      else
      {
          h = anchorNameHash(name);
          lname = TY_(tmbstrtolower)(lname);
      }
  
      for ( found = attribs->anchor_hash[h]; found != NULL; found = found->next )
      {
          if ( TY_(tmbstrcmp)(found->name, lname) == 0 )
              break;
      }
      
      TidyDocFree(doc, lname);
      if ( found )
          return found->node;
      return NULL;
  }
  
  /* free all anchors */
  void TY_(FreeAnchors)( TidyDocImpl* doc )
  {
      TidyAttribImpl* attribs = &doc->attribs;
      Anchor* a;
      uint h;
      for (h = 0; h < ANCHOR_HASH_SIZE; h++) {
          while (NULL != (a = attribs->anchor_hash[h]) )
          {
              attribs->anchor_hash[h] = a->next;
              FreeAnchor(doc, a);
          }
      }
  }
  
  /* public method for inititializing attribute dictionary */
  void TY_(InitAttrs)( TidyDocImpl* doc )
  {
      TidyClearMemory( &doc->attribs, sizeof(TidyAttribImpl) );
  #ifdef _DEBUG
      {
        /* Attribute ID is index position in Attribute type lookup table */
        uint ix;
        for ( ix=0; ix < N_TIDY_ATTRIBS; ++ix )
        {
          const Attribute* dict = &attribute_defs[ ix ];
          assert( (uint) dict->id == ix );
        }
      }
  #endif
  }
  
  /* free all declared attributes */
  static void FreeDeclaredAttributes( TidyDocImpl* doc )
  {
      TidyAttribImpl* attribs = &doc->attribs;
      Attribute* dict;
      while ( NULL != (dict = attribs->declared_attr_list) )
      {
          attribs->declared_attr_list = dict->next;
          attrsRemoveFromHash( doc, &doc->attribs, dict->name );
          TidyDocFree( doc, dict->name );
          TidyDocFree( doc, dict );
      }
  }
  
  void TY_(FreeAttrTable)( TidyDocImpl* doc )
  {
      attrsEmptyHash( doc, &doc->attribs );
      TY_(FreeAnchors)( doc );
      FreeDeclaredAttributes( doc );
  }
  
  void TY_(AppendToClassAttr)( TidyDocImpl* doc, AttVal *classattr, ctmbstr classname )
  {
      uint len = TY_(tmbstrlen)(classattr->value) +
          TY_(tmbstrlen)(classname) + 2;
      tmbstr s = (tmbstr) TidyDocAlloc( doc, len );
      s[0] = '\0';
      if (classattr->value)
      {
          TY_(tmbstrcpy)( s, classattr->value );
          TY_(tmbstrcat)( s, " " );
      }
      TY_(tmbstrcat)( s, classname );
      if (classattr->value)
          TidyDocFree( doc, classattr->value );
      classattr->value = s;
  }
  
  /* concatenate styles */
  static void AppendToStyleAttr( TidyDocImpl* doc, AttVal *styleattr, ctmbstr styleprop )
  {
      /*
      this doesn't handle CSS comments and
      leading/trailing white-space very well
      see http://www.w3.org/TR/css-style-attr
      */
      uint end = TY_(tmbstrlen)(styleattr->value);
  
      if (end >0 && styleattr->value[end - 1] == ';')
      {
          /* attribute ends with declaration seperator */
  
          styleattr->value = (tmbstr) TidyDocRealloc(doc, styleattr->value,
              end + TY_(tmbstrlen)(styleprop) + 2);
  
          TY_(tmbstrcat)(styleattr->value, " ");
          TY_(tmbstrcat)(styleattr->value, styleprop);
      }
      else if (end >0 && styleattr->value[end - 1] == '}')
      {
          /* attribute ends with rule set */
  
          styleattr->value = (tmbstr) TidyDocRealloc(doc, styleattr->value,
              end + TY_(tmbstrlen)(styleprop) + 6);
  
          TY_(tmbstrcat)(styleattr->value, " { ");
          TY_(tmbstrcat)(styleattr->value, styleprop);
          TY_(tmbstrcat)(styleattr->value, " }");
      }
      else
      {
          /* attribute ends with property value */
  
          styleattr->value = (tmbstr) TidyDocRealloc(doc, styleattr->value,
              end + TY_(tmbstrlen)(styleprop) + 3);
  
          if (end > 0)
              TY_(tmbstrcat)(styleattr->value, "; ");
          TY_(tmbstrcat)(styleattr->value, styleprop);
      }
  }
  
  /*
   the same attribute name can't be used
   more than once in each element
  */
  static Bool AttrsHaveSameName( AttVal* av1, AttVal* av2)
  {
      TidyAttrId id1, id2;
  
      id1 = AttrId(av1);
      id2 = AttrId(av2);
      if (id1 != TidyAttr_UNKNOWN && id2 != TidyAttr_UNKNOWN)
          return AttrsHaveSameId(av1, av2);
      if (id1 != TidyAttr_UNKNOWN || id2 != TidyAttr_UNKNOWN)
          return no;
      if (av1->attribute && av2->attribute)
          return TY_(tmbstrcmp)(av1->attribute, av2->attribute) == 0;
       return no;
  }
  
  void TY_(RepairDuplicateAttributes)( TidyDocImpl* doc, Node *node, Bool isXml )
  {
      AttVal *first;
  
      for (first = node->attributes; first != NULL;)
      {
          AttVal *second;
          Bool firstRedefined = no;
  
          if (!(first->asp == NULL && first->php == NULL))
          {
              first = first->next;
              continue;
          }
  
          for (second = first->next; second != NULL;)
          {
              AttVal *temp;
  
              if (!(second->asp == NULL && second->php == NULL
                    && AttrsHaveSameName(first, second)))
              {
                  second = second->next;
                  continue;
              }
  
              /* first and second attribute have same local name */
              /* now determine what to do with this duplicate... */
  
              if (!isXml
                  && attrIsCLASS(first) && cfgBool(doc, TidyJoinClasses)
                  && AttrHasValue(first) && AttrHasValue(second))
              {
                  /* concatenate classes */
  
                  TY_(AppendToClassAttr)(doc, first, second->value);
  
                  temp = second->next;
                  TY_(ReportAttrError)( doc, node, second, JOINING_ATTRIBUTE);
                  TY_(RemoveAttribute)( doc, node, second );
                  second = temp;
              }
              else if (!isXml
                       && attrIsSTYLE(first) && cfgBool(doc, TidyJoinStyles)
                       && AttrHasValue(first) && AttrHasValue(second))
              {
                  AppendToStyleAttr( doc, first, second->value );
  
                  temp = second->next;
                  TY_(ReportAttrError)( doc, node, second, JOINING_ATTRIBUTE);
                  TY_(RemoveAttribute)( doc, node, second );
                  second = temp;
              }
              else if ( cfg(doc, TidyDuplicateAttrs) == TidyKeepLast )
              {
                  temp = first->next;
                  TY_(ReportAttrError)( doc, node, first, REPEATED_ATTRIBUTE);
                  TY_(RemoveAttribute)( doc, node, first );
                  firstRedefined = yes;
                  first = temp;
                  second = second->next;
              }
              else /* TidyDuplicateAttrs == TidyKeepFirst */
              {
                  temp = second->next;
                  TY_(ReportAttrError)( doc, node, second, REPEATED_ATTRIBUTE);
                  TY_(RemoveAttribute)( doc, node, second );
                  second = temp;
              }
          }
          if (!firstRedefined)
              first = first->next;
      }
  }
  
  /* ignore unknown attributes for proprietary elements */
  const Attribute* TY_(CheckAttribute)( TidyDocImpl* doc, Node *node, AttVal *attval )
  {
      const Attribute* attribute = attval->dict;
  
      if ( attribute != NULL )
      {
          if (attrIsXML_LANG(attval) || attrIsXML_SPACE(attval))
          {
              doc->lexer->isvoyager = yes;
              if (!cfgBool(doc, TidyHtmlOut))
              {
                  TY_(SetOptionBool)(doc, TidyXhtmlOut, yes);
                  TY_(SetOptionBool)(doc, TidyXmlOut, yes);
              }
          }
  
          TY_(ConstrainVersion)(doc, AttributeVersions(node, attval));
          
          if (attribute->attrchk)
              attribute->attrchk( doc, node, attval );
      }
  
      return attribute;
  }
  
  Bool TY_(IsBoolAttribute)(AttVal *attval)
  {
      const Attribute *attribute = ( attval ? attval->dict : NULL );
      if ( attribute && attribute->attrchk == CH_BOOL )
          return yes;
      return no;
  }
  
  Bool TY_(attrIsEvent)( AttVal* attval )
  {
      TidyAttrId atid = AttrId( attval );
  
      return (atid == TidyAttr_OnAFTERUPDATE     ||
              atid == TidyAttr_OnBEFOREUNLOAD    ||
              atid == TidyAttr_OnBEFOREUPDATE    ||
              atid == TidyAttr_OnBLUR            ||
              atid == TidyAttr_OnCHANGE          ||
              atid == TidyAttr_OnCLICK           ||
              atid == TidyAttr_OnDATAAVAILABLE   ||
              atid == TidyAttr_OnDATASETCHANGED  ||
              atid == TidyAttr_OnDATASETCOMPLETE ||
              atid == TidyAttr_OnDBLCLICK        ||
              atid == TidyAttr_OnERRORUPDATE     ||
              atid == TidyAttr_OnFOCUS           ||
              atid == TidyAttr_OnKEYDOWN         ||
              atid == TidyAttr_OnKEYPRESS        ||
              atid == TidyAttr_OnKEYUP           ||
              atid == TidyAttr_OnLOAD            ||
              atid == TidyAttr_OnMOUSEDOWN       ||
              atid == TidyAttr_OnMOUSEMOVE       ||
              atid == TidyAttr_OnMOUSEOUT        ||
              atid == TidyAttr_OnMOUSEOVER       ||
              atid == TidyAttr_OnMOUSEUP         ||
              atid == TidyAttr_OnRESET           ||
              atid == TidyAttr_OnROWENTER        ||
              atid == TidyAttr_OnROWEXIT         ||
              atid == TidyAttr_OnSELECT          ||
              atid == TidyAttr_OnSUBMIT          ||
              atid == TidyAttr_OnUNLOAD);
  }
  
  static void CheckLowerCaseAttrValue( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      tmbstr p;
      Bool hasUpper = no;
      
      if (!AttrHasValue(attval))
          return;
  
      p = attval->value;
      
      while (*p)
      {
          if (TY_(IsUpper)(*p)) /* #501230 - fix by Terry Teague - 09 Jan 02 */
          {
              hasUpper = yes;
              break;
          }
          p++;
      }
  
      if (hasUpper)
      {
          Lexer* lexer = doc->lexer;
          if (lexer->isvoyager)
              TY_(ReportAttrError)( doc, node, attval, ATTR_VALUE_NOT_LCASE);
    
          if ( lexer->isvoyager || cfgBool(doc, TidyLowerLiterals) )
              attval->value = TY_(tmbstrtolower)(attval->value);
      }
  }
  
  /* Issue #588 - use simple macros only!
     Seems 'isalnum(c)' is undefined and can
     cause an assert or a SIGSEGV in some libraries
     if 'c' is not EOF, or in the range 0 to 0xff,
     so avoid using it.
  */
  #define ISUPPER(a) ((a >= 'A') && (a <= 'Z'))
  #define ISLOWER(a) ((a >= 'a') && (a <= 'z'))
  #define ISNUMERIC(a) ((a >= '0') && (a <= '9'))
  #define ISALNUM(a) (ISUPPER(a) || ISLOWER(a) || ISNUMERIC(a))
  
  static Bool IsURLCodePoint( ctmbstr p, uint *increment )
  {
      uint c;
      *increment = TY_(GetUTF8)( p, &c ) + 1;
  
      return ISALNUM( c ) ||
          c == '%' ||    /* not a valid codepoint, but an escape sequence */
          c == '#' ||    /* not a valid codepoint, but a delimiter */
          c == '!' ||
          c == '$' ||
          c == '&' ||
          c == '\'' ||
          c == '(' ||
          c == ')' ||
          c == '*' ||
          c == '+' ||
          c == ',' ||
          c == '-' ||
          c == '.' ||
          c == '/' ||
          c == ':' ||
          c == ';' ||
          c == '=' ||
          c == '?' ||
          c == '@' ||
          c == '_' ||
          c == '~' ||
          (c >= 0x00A0 && c <= 0xD7FF) ||
          (c >= 0xE000 && c <= 0xFDCF) ||
          (c >= 0xFDF0 && c <= 0xFFEF) ||
          (c >= 0x10000 && c <= 0x1FFFD) ||
          (c >= 0x20000 && c <= 0x2FFFD) ||
          (c >= 0x30000 && c <= 0x3FFFD) ||
          (c >= 0x40000 && c <= 0x4FFFD) ||
          (c >= 0x50000 && c <= 0x5FFFD) ||
          (c >= 0x60000 && c <= 0x6FFFD) ||
          (c >= 0x70000 && c <= 0x7FFFD) ||
          (c >= 0x80000 && c <= 0x8FFFD) ||
          (c >= 0x90000 && c <= 0x9FFFD) ||
          (c >= 0xA0000 && c <= 0xAFFFD) ||
          (c >= 0xB0000 && c <= 0xBFFFD) ||
          (c >= 0xC0000 && c <= 0xCFFFD) ||
          (c >= 0xD0000 && c <= 0xDFFFD) ||
          (c >= 0xE0000 && c <= 0xEFFFD) ||
          (c >= 0xF0000 && c <= 0xFFFFD) ||
          (c >= 0x100000 && c <= 0x10FFFD);
  }
  
  void TY_(CheckUrl)( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      tmbchar c;
      tmbstr dest, p;
      uint escape_count = 0, backslash_count = 0, bad_codepoint_count = 0;
      uint i, pos = 0;
      uint len;
      uint increment;
      Bool isJavascript = no;
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      p = attval->value;
  
      isJavascript =
          TY_(tmbstrncmp)(p,"javascript:",sizeof("javascript:")-1)==0;
  
      for (i = 0; '\0' != (c = p[i]); ++i)
      {
          if (c == '\\')
          {
              ++backslash_count;
              if ( cfgBool(doc, TidyFixBackslash) && !isJavascript)
                  p[i] = '/';
          }
          else if ((c > 0x7e) || (c <= 0x20) || (strchr("<>", c)))
              ++escape_count;
      }
  
      while ( *p != 0 )
      {
          if ( !IsURLCodePoint( p, &increment ) )
              ++bad_codepoint_count;
           p = p + increment;
      }
      p = attval->value;
  
      if ( cfgBool(doc, TidyFixUri) && escape_count )
      {
          Bool hadnonspace = no;
          len = TY_(tmbstrlen)(p) + escape_count * 2 + 1;
          dest = (tmbstr) TidyDocAlloc(doc, len);
   
          for (i = 0; 0 != (c = p[i]); ++i)
          {
              if ((c > 0x7e) || (c <= 0x20) || (strchr("<>", c)))
              {
                  if (c == 0x20)
                  {
                      /* #345 - special case for leading spaces - discard */
                      if (hadnonspace)
                          pos += sprintf( dest + pos, "%%%02X", (byte)c );
                  }
                  else
                  {
                      pos += sprintf( dest + pos, "%%%02X", (byte)c );
                      hadnonspace = yes;
                  }
              }
              else
              {
                  hadnonspace = yes;
                  dest[pos++] = c;
              }
          }
          dest[pos] = 0;
  
          TidyDocFree(doc, attval->value);
          attval->value = dest;
      }
      if ( backslash_count )
      {
          if ( cfgBool(doc, TidyFixBackslash) && !isJavascript )
              TY_(ReportAttrError)( doc, node, attval, FIXED_BACKSLASH );
          else
              TY_(ReportAttrError)( doc, node, attval, BACKSLASH_IN_URI );
      }
      if ( escape_count )
      {
          if ( cfgBool(doc, TidyFixUri) )
              TY_(ReportAttrError)( doc, node, attval, ESCAPED_ILLEGAL_URI);
          else if ( !(TY_(HTMLVersion)(doc) & VERS_HTML5) )
              TY_(ReportAttrError)( doc, node, attval, ILLEGAL_URI_REFERENCE);
  
          doc->badChars |= BC_INVALID_URI;
      }
      if ( bad_codepoint_count )
      {
          TY_(ReportAttrError)( doc, node, attval, ILLEGAL_URI_CODEPOINT );
      }
  }
  
  /* RFC 2396, section 4.2 states:
       "[...] in the case of HTML's FORM element, [...] an
       empty URI reference represents the base URI of the
       current document and should be replaced by that URI
       when transformed into a request."
  */
  void CheckAction( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (AttrHasValue(attval))
          TY_(CheckUrl)( doc, node, attval );
  }
  
  void CheckScript( TidyDocImpl* ARG_UNUSED(doc), Node* ARG_UNUSED(node),
                    AttVal* ARG_UNUSED(attval))
  {
  }
  
  Bool TY_(IsValidHTMLID)(ctmbstr id)
  {
      ctmbstr s = id;
  
      if (!s)
          return no;
  
      while (*s)
          if (TY_(IsHTMLSpace)(*s++))
              return no;
  
      return yes;
  
  }
  
  Bool TY_(IsValidXMLID)(ctmbstr id)
  {
      ctmbstr s = id;
      tchar c;
  
      if (!s)
          return no;
  
      c = *s++;
      if (c > 0x7F)
          s += TY_(GetUTF8)(s, &c);
  
      if (!(TY_(IsXMLLetter)(c) || c == '_' || c == ':'))
          return no;
  
      while (*s)
      {
          c = (unsigned char)*s;
  
          if (c > 0x7F)
              s += TY_(GetUTF8)(s, &c);
  
          ++s;
  
          if (!TY_(IsXMLNamechar)(c))
              return no;
      }
  
      return yes;
  }
  
  static Bool IsValidNMTOKEN(ctmbstr name)
  {
      ctmbstr s = name;
      tchar c;
  
      if (!s)
          return no;
  
      while (*s)
      {
          c = (unsigned char)*s;
  
          if (c > 0x7F)
              s += TY_(GetUTF8)(s, &c);
  
          ++s;
  
          if (!TY_(IsXMLNamechar)(c))
              return no;
      }
  
      return yes;
  }
  
  static Bool AttrValueIsAmong(AttVal *attval, ctmbstr const list[])
  {
      const ctmbstr *v;   
      for (v = list; *v; ++v)
          if (AttrValueIs(attval, *v))
              return yes;
      return no;
  }
  
  static void CheckAttrValidity( TidyDocImpl* doc, Node *node, AttVal *attval,
                                 ctmbstr const list[])
  {
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      CheckLowerCaseAttrValue( doc, node, attval );
  
      if (!AttrValueIsAmong(attval, list))
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  }
  
  void CheckName( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      Node *old;
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      if ( TY_(IsAnchorElement)(doc, node) )
      {
          if (cfgBool(doc, TidyXmlOut) && !IsValidNMTOKEN(attval->value))
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  
          if ((old = GetNodeByAnchor(doc, attval->value)) &&  old != node)
          {
              if (node->implicit) /* Is #709 - improve warning text */
                  TY_(ReportAttrError)(doc, node, attval, ANCHOR_DUPLICATED);
              else
                  TY_(ReportAttrError)( doc, node, attval, ANCHOR_NOT_UNIQUE);
          }
          else
              AddAnchor( doc, attval->value, node );
      }
  }
  
  void CheckId( TidyDocImpl* doc, Node *node, AttVal *attval )
  {
      Lexer* lexer = doc->lexer;
      Node *old;
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      if (!TY_(IsValidHTMLID)(attval->value))
      {
          if (lexer->isvoyager && TY_(IsValidXMLID)(attval->value))
              TY_(ReportAttrError)( doc, node, attval, XML_ID_SYNTAX);
          else
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
  
      if ((old = GetNodeByAnchor(doc, attval->value)) &&  old != node)
      {
          if (node->implicit) /* Is #709 - improve warning text */
              TY_(ReportAttrError)(doc, node, attval, ANCHOR_DUPLICATED);
          else
              TY_(ReportAttrError)( doc, node, attval, ANCHOR_NOT_UNIQUE);
      }
      else
          AddAnchor( doc, attval->value, node );
  }
  
  void CheckIs( TidyDocImpl* doc, Node *node, AttVal *attval )
  {
      const char *ptr;
      Bool go = yes;
  
      /* `is` MUST NOT be in an autonomous custom tag */
      ptr = strchr(node->element, '-');
      if ( ( ptr && (ptr - node->element > 0) ) )
      {
          TY_(ReportAttrError)( doc, node, attval, ATTRIBUTE_IS_NOT_ALLOWED);
      }
  
      /* Even if we fail the above test, we'll continue to emit reports because
         the user should *also* know that his attribute values are wrong, even
         if they should't be in custom tags anyway. */
  
      /* `is` MUST have a value */
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      /* `is` MUST contain a hyphen and no space. */
      ptr = strchr(attval->value, '-');
      go = ( ptr && (ptr - attval->value > 0) );
      ptr = strchr(attval->value, ' ');
      go = go & (ptr == NULL);
      if ( !go )
      {
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
  }
  
  void CheckBool( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (!AttrHasValue(attval))
          return;
  
      CheckLowerCaseAttrValue( doc, node, attval );
  }
  
  void CheckAlign( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"left", "right", "center", "justify", NULL};
  
      /* IMG, OBJECT, APPLET and EMBED use align for vertical position */
      if (node->tag && (node->tag->model & CM_IMG))
      {
          CheckValign( doc, node, attval );
          return;
      }
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      CheckLowerCaseAttrValue( doc, node, attval);
  
      /* currently CheckCaption(...) takes care of the remaining cases */
      if (nodeIsCAPTION(node))
          return;
  
      if (!AttrValueIsAmong(attval, values))
      {
          /* align="char" is allowed for elements with CM_TABLE|CM_ROW
             except CAPTION which is excluded above, */
          if( !(AttrValueIs(attval, "char")
                && TY_(nodeHasCM)(node, CM_TABLE|CM_ROW)) )
               TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
  }
  
  void CheckValign( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"top", "middle", "bottom", "baseline", NULL};
      ctmbstr const values2[] = {"left", "right", NULL};
      ctmbstr const valuesp[] = {"texttop", "absmiddle", "absbottom",
                                 "textbottom", NULL};
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      CheckLowerCaseAttrValue( doc, node, attval );
  
      if (AttrValueIsAmong(attval, values))
      {
              /* all is fine */
      }
      else if (AttrValueIsAmong(attval, values2))
      {
          if (!(node->tag && (node->tag->model & CM_IMG)))
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
      else if (AttrValueIsAmong(attval, valuesp))
      {
          TY_(ConstrainVersion)( doc, VERS_PROPRIETARY );
          TY_(ReportAttrError)( doc, node, attval, PROPRIETARY_ATTR_VALUE);
      }
      else
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  }
  
  void CheckLength( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      tmbstr p;
      
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      /* don't check for <col width=...> and <colgroup width=...> */
      if (attrIsWIDTH(attval) && (nodeIsCOL(node) || nodeIsCOLGROUP(node)))
          return;
  
      p = attval->value;
      
      if (!TY_(IsDigit)(*p++))
      {
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
      else
      {
          Bool percentFound = no;
          while (*p)
          {
              if (!percentFound && *p == '%')
              {
                  percentFound = yes;
              }
              else if (percentFound || !TY_(IsDigit)(*p))
              {
                  TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
                  break;
              }
  
              ++p;
          }
      }
  }
  
  void CheckTarget( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"_blank", "_self", "_parent", "_top", NULL};
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      /* target names must begin with A-Za-z ... */
      if (TY_(IsLetter)(attval->value[0]))
          return;
  
      /* or be one of the allowed list */
      if (!AttrValueIsAmong(attval, values))
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  }
  
  void CheckFsubmit( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"get", "post", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  void CheckClear( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"none", "left", "right", "all", NULL};
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          if (attval->value == NULL)
              attval->value = TY_(tmbstrdup)( doc->allocator, "none" );
          return;
      }
  
      CheckLowerCaseAttrValue( doc, node, attval );
          
      if (!AttrValueIsAmong(attval, values))
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  }
  
  void CheckShape( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"rect", "default", "circle", "poly", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  void CheckScope( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"row", "rowgroup", "col", "colgroup", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  void CheckNumber( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      tmbstr p;
      
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      /* don't check <frameset cols=... rows=...> */
      if ( nodeIsFRAMESET(node) &&
          (attrIsCOLS(attval) || attrIsROWS(attval)))
       return;
  
      p  = attval->value;
      
      /* font size may be preceded by + or - */
      if ( nodeIsFONT(node) && (*p == '+' || *p == '-') )
          ++p;
      /* tabindex may be preceeded by - */
      if (attval->attribute && (strcmp(attval->attribute,"tabindex") == 0) && (*p == '-'))
          ++p;
  
      while (*p)
      {
          if (!TY_(IsDigit)(*p))
          {
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
              break;
          }
          ++p;
      }
  }
  
  /* check hexadecimal color value */
  static Bool IsValidColorCode(ctmbstr color)
  {
      uint i;
  
      if (TY_(tmbstrlen)(color) != 6)
          return no;
  
      /* check if valid hex digits and letters */
      for (i = 0; i < 6; i++)
          if (!TY_(IsDigit)(color[i]) && !strchr("abcdef", TY_(ToLower)(color[i])))
              return no;
  
      return yes;
  }
  
  /* check color syntax and beautify value by option */
  void CheckColor( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      Bool valid = no;
      tmbstr given;
  
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      given = attval->value;
  
      /* 727851 - add hash to hash-less color values */
      if (given[0] != '#' && (valid = IsValidColorCode(given)))
      {
          tmbstr cp, s;
  
          cp = s = (tmbstr) TidyDocAlloc(doc, 2 + TY_(tmbstrlen)(given));
          *cp++ = '#';
          while ('\0' != (*cp++ = *given++))
              continue;
  
          TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE_REPLACED);
  
          TidyDocFree(doc, attval->value);
          given = attval->value = s;
      }
  
      if (!valid && given[0] == '#')
          valid = IsValidColorCode(given + 1);
  
      if (valid && given[0] == '#' && cfgBool(doc, TidyReplaceColor))
      {
          ctmbstr newName = GetColorName(given, TY_(IsHTML5Mode)(doc));
  
          if (newName)
          {
              TidyDocFree(doc, attval->value);
              given = attval->value = TY_(tmbstrdup)(doc->allocator, newName);
          }
      }
  
      /* if it is not a valid color code, it is a color name */
      if (!valid)
          valid = GetColorCode(given, TY_(IsHTML5Mode)(doc)) != NULL;
  
      if (valid && given[0] == '#')
          attval->value = TY_(tmbstrtoupper)(attval->value);
      else if (valid)
          attval->value = TY_(tmbstrtolower)(attval->value);
  
      if (!valid)
          TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
  }
  
  /* check valuetype attribute for element param */
  void CheckVType( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"data", "object", "ref", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  /* checks scrolling attribute */
  void CheckScroll( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"no", "auto", "yes", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  /* checks dir attribute */
  void CheckTextDir( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values4[] = { "rtl", "ltr", NULL };
      /* PR #712 - add 'auto' for HTML5 - @doronbehar */
      ctmbstr const values5[] = { "rtl", "ltr", "auto", NULL };
      CheckAttrValidity(doc, node, attval,
          (TY_(IsHTML5Mode)(doc) ? values5 : values4));
  }
  
  /* checks lang and xml:lang attributes */
  void CheckLang( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      /* empty xml:lang is allowed through XML 1.0 SE errata */
      if (!AttrHasValue(attval) && !attrIsXML_LANG(attval))
      {
          if ( cfg(doc, TidyAccessibilityCheckLevel) == 0 )
          {
              TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE );
          }
          return;
      }
  }
  
  /* checks loading attribute */
  void CheckLoading( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const values[] = {"lazy", "eager", NULL};
      CheckAttrValidity( doc, node, attval, values );
  }
  
  /* checks type attribute */
  void CheckType( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      ctmbstr const valuesINPUT[] = {
          "text", "password", "checkbox", "radio", "submit", "reset", "file",
          "hidden", "image", "button", "color", "date", "datetime",
          "datetime-local", "email", "month", "number", "range", "search",
          "tel", "time", "url", "week", NULL};
      ctmbstr const valuesBUTTON[] = {"button", "submit", "reset", NULL};
      ctmbstr const valuesUL[] = {"disc", "square", "circle", NULL};
      ctmbstr const valuesOL[] = {"1", "a", "i", NULL};
  
      if (nodeIsINPUT(node))
          CheckAttrValidity( doc, node, attval, valuesINPUT );
      else if (nodeIsBUTTON(node))
          CheckAttrValidity( doc, node, attval, valuesBUTTON );
      else if (nodeIsUL(node))
          CheckAttrValidity( doc, node, attval, valuesUL );
      else if (nodeIsOL(node))
      {
          if (!AttrHasValue(attval))
          {
              TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
              return;
          }
          if (!AttrValueIsAmong(attval, valuesOL))
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
      else if (nodeIsLI(node))
      {
          if (!AttrHasValue(attval))
          {
              TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
              return;
          }
          if (AttrValueIsAmong(attval, valuesUL))
              CheckLowerCaseAttrValue( doc, node, attval );
          else if (!AttrValueIsAmong(attval, valuesOL))
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
      }
      return;
  }
  
  static void CheckDecimal( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      tmbstr p;
      Bool hasPoint = no;
  
      p  = attval->value;
  
      /* Allow leading sign */
      if (*p == '+' || *p == '-')
          ++p;
  
      while (*p)
      {
          /* Allow a single decimal point */
          if (*p == '.')
          {
              if (!hasPoint)
                  hasPoint = yes;
              else
                  TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
                  break;
          }
          
          if (!TY_(IsDigit)(*p))
          {
              TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
              break;
          }
          ++p;
      }
  }
  
  static Bool IsSvgPaintAttr(AttVal *attval)
  {
      return attrIsCOLOR(attval)
          || attrIsSVG_FILL(attval)
          || attrIsSVG_FILLRULE(attval)
          || attrIsSVG_STROKE(attval)
          || attrIsSVG_STROKEDASHARRAY(attval)
          || attrIsSVG_STROKEDASHOFFSET(attval)
          || attrIsSVG_STROKELINECAP(attval)
          || attrIsSVG_STROKELINEJOIN(attval)
          || attrIsSVG_STROKEMITERLIMIT(attval)
          || attrIsSVG_STROKEWIDTH(attval)
          || attrIsSVG_COLORINTERPOLATION(attval)
          || attrIsSVG_COLORRENDERING(attval)
          || attrIsSVG_OPACITY(attval)
          || attrIsSVG_STROKEOPACITY(attval)
          || attrIsSVG_FILLOPACITY(attval);
  }
  
  /* Check SVG attributes */
  static void CheckSvgAttr( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (!nodeIsSVG(node))
      {
          TY_(ReportAttrError)(doc, node, attval, ATTRIBUTE_IS_NOT_ALLOWED);
          return;
      }
  
      /* Issue #903 - check SVG paint attributes */
      if (IsSvgPaintAttr(attval))
      {
          /* all valid paint attributes have values */
          if (!AttrHasValue(attval))
          {
              TY_(ReportAttrError)(doc, node, attval, MISSING_ATTR_VALUE);
              return;
          }
          /* all paint attributes support an 'inherit' value,
          per https://dev.w3.org/SVG/profiles/1.1F2/publish/painting.html#SpecifyingPaint */
          if (AttrValueIs(attval, "inherit"))
          {
              return;
          }
  
          /* check paint datatypes
          see https://dev.w3.org/SVG/profiles/1.1F2/publish/painting.html#SpecifyingPaint
          */
          if (attrIsSVG_FILL(attval) || attrIsSVG_STROKE(attval))
          {
              /* TODO: support funciri */
              static ctmbstr const values[] = {
                  "none", "currentColor", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  CheckColor(doc, node, attval);
          } 
          else if (attrIsSVG_FILLRULE(attval))
          {
              static ctmbstr const values[] = {"nonzero", "evenodd", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE);
          }
          else if (attrIsSVG_STROKEDASHARRAY(attval))
          {
              static ctmbstr const values[] = {"none", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
              {
                  /* TODO: process dash arrays */
              }
          }
          else if (attrIsSVG_STROKEDASHOFFSET(attval))
          {
              CheckLength(doc, node, attval);
          }
          else if (attrIsSVG_STROKELINECAP(attval))
          {
              static ctmbstr const values[] = {"butt", "round", "square", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE);
          }
          else if (attrIsSVG_STROKELINEJOIN(attval))
          {
              static ctmbstr const values[] = {"miter", "round", "bevel", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE);
          }
          else if (attrIsSVG_STROKEMITERLIMIT(attval))
          {
              CheckNumber(doc, node, attval);
          }
          else if (attrIsSVG_STROKEWIDTH(attval))
          {
              CheckLength(doc, node, attval);
          }
          else if (attrIsSVG_COLORINTERPOLATION(attval))
          {
              static ctmbstr const values[] = {"auto", "sRGB", "linearRGB", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE);
          }
          else if (attrIsSVG_COLORRENDERING(attval))
          {
              static ctmbstr const values[] = {
                  "auto", "optimizeSpeed", "optimizeQuality", NULL};
  
              if (AttrValueIsAmong(attval, values))
                  CheckLowerCaseAttrValue(doc, node, attval);
              else
                  TY_(ReportAttrError)(doc, node, attval, BAD_ATTRIBUTE_VALUE);
          }
          else if(attrIsSVG_OPACITY(attval))
          {
              CheckDecimal(doc, node, attval);
          }
          else if(attrIsSVG_STROKEOPACITY(attval))
          {
              CheckDecimal(doc, node, attval);
          }
          else if(attrIsSVG_FILLOPACITY(attval))
          {
              CheckDecimal(doc, node, attval);
          }
      }
  }
  
  static
  AttVal *SortAttVal( TidyDocImpl* doc, AttVal* list, TidyAttrSortStrategy strat );
  
  void TY_(SortAttributes)(TidyDocImpl* doc, Node* node, TidyAttrSortStrategy strat)
  {
      while (node)
      {
          node->attributes = SortAttVal( doc, node->attributes, strat );
          if (node->content)
              TY_(SortAttributes)(doc, node->content, strat);
          node = node->next;
      }
  }
  
  /**
  * Attribute sorting contributed by Adrian Wilkins, 2007
  * 
  * Portions copyright Simon Tatham 2001.
  *
  * Merge sort algortithm adpated from listsort.c linked from 
  * http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
  * 
  * Original copyright notice proceeds below.
  * 
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
  * files (the "Software"), to deal in the Software without
  * restriction, including without limitation the rights to use,
  * copy, modify, merge, publish, distribute, sublicense, and/or
  * sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following
  * conditions:
  * 
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  * 
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT.  IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR
  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
  
  typedef int(*ptAttValComparator)(AttVal *one, AttVal *two, ctmbstr *list);
  
  /* Returns the index of the item in the array, or -1 if not in the array */
  static
  int indexof( ctmbstr item, ctmbstr *list )
  {
      if ( list )
      {
          uint i = 0;
          while ( list[i] != NULL ) {
              if ( TY_(tmbstrcasecmp)(item, list[i]) == 0 )
                  return i;
              i++;
          }
      }
  
      return -1;
  }
  
  /* Comparison function for TidySortAttrAlpha. Will also consider items in
     the passed in list as higher-priority, and will group them first.
   */
  static
  int AlphaComparator(AttVal *one, AttVal *two, ctmbstr *list)
  {
      int oneIndex = indexof( one->attribute, list );
      int twoIndex = indexof( two->attribute, list );
  
      /* If both on the list, the lower index has priority. */
      if ( oneIndex >= 0 && twoIndex >= 0 )
          return oneIndex < twoIndex ? -1 : 1;
  
      /* If A on the list but B not on the list, then A has priority. */
      if ( oneIndex >= 0 && twoIndex == -1 )
          return -1;
  
      /* If A not on the list but B is on the list, then B has priority. */
      if ( oneIndex == -1 && twoIndex >= 0 )
          return 1;
  
      /* Otherwise nothing is on the list, so just compare strings. */
      return TY_(tmbstrcmp)(one->attribute, two->attribute);
  }
  
  
  /* Comparison function for prioritizing list items. It doesn't otherwise
     sort.
   */
  static
  int PriorityComparator(AttVal *one, AttVal *two, ctmbstr *list)
  {
      int oneIndex = indexof( one->attribute, list );
      int twoIndex = indexof( two->attribute, list );
  
      /* If both on the list, the lower index has priority. */
      if ( oneIndex >= 0 && twoIndex >= 0 )
          return oneIndex < twoIndex ? -1 : 1;
  
      /* If A on the list but B not on the list, then A has priority. */
      if ( oneIndex >= 0 && twoIndex == -1 )
          return -1;
  
      /* If A not on the list but B is on the list, then B has priority. */
      if ( oneIndex == -1 && twoIndex >= 0 )
          return 1;
  
      /* Otherwise nothing is on the list, so just mark them as the same. */
      return 0;
  }
  
  
  /* The "factory method" that returns a pointer to the comparator function */
  static
  ptAttValComparator GetAttValComparator(TidyAttrSortStrategy strat, ctmbstr *list)
  {
      switch (strat)
      {
      case TidySortAttrAlpha:
          return AlphaComparator;
      case TidySortAttrNone:
          if ( list && list[0] )
              return PriorityComparator;
          break;
      }
      return 0;
  }
  
  /* The sort routine */
  static
  AttVal *SortAttVal( TidyDocImpl* doc, AttVal *list, TidyAttrSortStrategy strat)
  {
      /* Get the list from the passed-in tidyDoc. */
      ctmbstr* priorityList = (ctmbstr*)doc->attribs.priorityAttribs.list;
  
      ptAttValComparator ptComparator = GetAttValComparator(strat, priorityList);
      AttVal *p, *q, *e, *tail;
      int insize, nmerges, psize, qsize, i;
  
      /*
      * Silly special case: if `list' was passed in as NULL, return
      * NULL immediately.
      */
      if (!list)
          return NULL;
  
      /* If no comparator, return the list as-is */
      if (ptComparator == 0)
          return list;
  
      insize = 1;
  
      while (1) {
          p = list;
          list = NULL;
          tail = NULL;
  
          nmerges = 0;  /* count number of merges we do in this pass */
  
          while (p) {
              nmerges++;  /* there exists a merge to be done */
              /* step `insize' places along from p */
              q = p;
              psize = 0;
              for (i = 0; i < insize; i++) {
                  psize++;
                  q = q->next;
                  if(!q) break;
              }
  
              /* if q hasn't fallen off end, we have two lists to merge */
              qsize = insize;
  
              /* now we have two lists; merge them */
              while (psize > 0 || (qsize > 0 && q)) {
  
                  /* decide whether next element of merge comes from p or q */
                  if (psize == 0) {
                      /* p is empty; e must come from q. */
                      e = q; q = q->next; qsize--;
                  } else if (qsize == 0 || !q) {
                      /* q is empty; e must come from p. */
                      e = p; p = p->next; psize--;
                  } else if (ptComparator(p,q, priorityList) <= 0) {
                      /* First element of p is lower (or same);
                      * e must come from p. */
                      e = p; p = p->next; psize--;
                  } else {
                      /* First element of q is lower; e must come from q. */
                      e = q; q = q->next; qsize--;
                  }
  
                  /* add the next element to the merged list */
                  if (tail) {
                      tail->next = e;
                  } else {
                      list = e;
                  }
  
                  tail = e;
              }
  
              /* now p has stepped `insize' places along, and q has too */
              p = q;
          }
  
          tail->next = NULL;
  
          /* If we have done only one merge, we're finished. */
          if (nmerges <= 1)   /* allow for nmerges==0, the empty list case */
              return list;
  
          /* Otherwise repeat, merging lists twice the size */
          insize *= 2;
      }
  }
  
  /* RDFA support checkers
   *
   */
  
  /* CheckRDFAPrefix - ensure the prefix attribute value is
   * correct
   *
   * @prefix takes prefix value pairs in the form:
   * 
   *      NCName ':' ' '+ AnyURI
   */
  
  void CheckRDFaPrefix ( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
      /* Copy the attribute value so we can split it */
      if (attval->value) {
          tmbstr t, tPtr ;
  
          uint prefixCount = 0;
          /* isPrefix toggles - start at 1 and change to 0 as we
           * iterate over the components of the value */
          uint isPrefix = 1;
  
          /* Copy it over */
  
          uint len = TY_(tmbstrlen)(attval->value);
          tmbstr s = (tmbstr) TidyDocAlloc( doc, len + 1 );
          s[0] = '\0';
          TY_(tmbstrcpy)( s, attval->value );
  
          /* iterate over value */
          tPtr = s;
  
          while ( ( t = strtok(tPtr, " ") ) != NULL ) {
              tPtr = NULL;
              if (isPrefix) {
                  /* this piece should be a prefix */
                  /* prefix rules are that it can have any
                   * character except a colon - that one must be
                   * at the end */
                  tmbstr i = strchr(t, ':') ;
                  if (i == NULL) {
                      /* no colon - bad! */
                      TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
                  } else if (i != ( t + TY_(tmbstrlen)(t) - 1) ) {
                      /* not at the end - also bad */
                      TY_(ReportAttrError)( doc, node, attval, BAD_ATTRIBUTE_VALUE);
                  }
              } else {
                  /* this piece should be a URL */
                  prefixCount ++;
              }
              isPrefix = !isPrefix;
          }
          TidyDocFree( doc, s ) ;
      }
  }
  
  /* CheckRDFaTerm - are terms valid
   *
   */
  
  void CheckRDFaTerm ( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
  }
  
  /* CheckRDFaSafeCURIE - is a CURIE legal
   *
   */
  
  void CheckRDFaSafeCURIE ( TidyDocImpl* doc, Node *node, AttVal *attval)
  {
      if (!AttrHasValue(attval))
      {
          TY_(ReportAttrError)( doc, node, attval, MISSING_ATTR_VALUE);
          return;
      }
  
  }
  
  /*
   * local variables:
   * mode: c
   * indent-tabs-mode: nil
   * c-basic-offset: 4
   * eval: (c-set-offset 'substatement-open 0)
   * end:
   */
  