text: /* ------------------------------------------------------------------------
  
     Python Codec Registry and support functions
  
  Written by Marc-Andre Lemburg (mal@lemburg.com).
  
  Copyright (c) Corporation for National Research Initiatives.
  
     ------------------------------------------------------------------------ */
  
  #include "Python.h"
  #include <ctype.h>
  
  /* --- Codec Registry ----------------------------------------------------- */
  
  /* Import the standard encodings package which will register the first
     codec search function.
  
     This is done in a lazy way so that the Unicode implementation does
     not downgrade startup time of scripts not needing it.
  
     ImportErrors are silently ignored by this function. Only one try is
     made.
  
  */
  
  static int _PyCodecRegistry_Init(void); /* Forward */
  
  int PyCodec_Register(PyObject *search_function)
  {
      PyInterpreterState *interp = PyThreadState_GET()->interp;
      if (interp->codec_search_path == NULL && _PyCodecRegistry_Init())
  	goto onError;
      if (search_function == NULL) {
  	PyErr_BadArgument();
  	goto onError;
      }
      if (!PyCallable_Check(search_function)) {
  	PyErr_SetString(PyExc_TypeError, "argument must be callable");
  	goto onError;
      }
      return PyList_Append(interp->codec_search_path, search_function);
  
   onError:
      return -1;
  }
  
  /* Convert a string to a normalized Python string: all characters are
     converted to lower case, spaces are replaced with underscores. */
  
  static
  PyObject *normalizestring(const char *string)
  {
      register size_t i;
      size_t len = strlen(string);
      char *p;
      PyObject *v;
  
      if (len > PY_SSIZE_T_MAX) {
  	PyErr_SetString(PyExc_OverflowError, "string is too large");
  	return NULL;
      }
  
      p = PyMem_Malloc(len + 1);
      if (p == NULL)
          return NULL;
      for (i = 0; i < len; i++) {
          register char ch = string[i];
          if (ch == ' ')
              ch = '-';
          else
              ch = tolower(Py_CHARMASK(ch));
  	p[i] = ch;
      }
      p[i] = '\0';
      v = PyUnicode_FromString(p);
      if (v == NULL)
          return NULL;
      PyMem_Free(p);
      return v;
  }
  
  /* Lookup the given encoding and return a tuple providing the codec
     facilities.
  
     The encoding string is looked up converted to all lower-case
     characters. This makes encodings looked up through this mechanism
     effectively case-insensitive.
  
     If no codec is found, a LookupError is set and NULL returned.
  
     As side effect, this tries to load the encodings package, if not
     yet done. This is part of the lazy load strategy for the encodings
     package.
  
  */
  
  PyObject *_PyCodec_Lookup(const char *encoding)
  {
      PyInterpreterState *interp;
      PyObject *result, *args = NULL, *v;
      Py_ssize_t i, len;
  
      if (encoding == NULL) {
  	PyErr_BadArgument();
  	goto onError;
      }
  
      interp = PyThreadState_GET()->interp;
      if (interp->codec_search_path == NULL && _PyCodecRegistry_Init())
  	goto onError;
  
      /* Convert the encoding to a normalized Python string: all
         characters are converted to lower case, spaces and hyphens are
         replaced with underscores. */
      v = normalizestring(encoding);
      if (v == NULL)
  	goto onError;
      PyUnicode_InternInPlace(&v);
  
      /* First, try to lookup the name in the registry dictionary */
      result = PyDict_GetItem(interp->codec_search_cache, v);
      if (result != NULL) {
  	Py_INCREF(result);
  	Py_DECREF(v);
  	return result;
      }
  
      /* Next, scan the search functions in order of registration */
      args = PyTuple_New(1);
      if (args == NULL)
  	goto onError;
      PyTuple_SET_ITEM(args,0,v);
  
      len = PyList_Size(interp->codec_search_path);
      if (len < 0)
  	goto onError;
      if (len == 0) {
  	PyErr_SetString(PyExc_LookupError,
  			"no codec search functions registered: "
  			"can't find encoding");
  	goto onError;
      }
  
      for (i = 0; i < len; i++) {
  	PyObject *func;
  
  	func = PyList_GetItem(interp->codec_search_path, i);
  	if (func == NULL)
  	    goto onError;
  	result = PyEval_CallObject(func, args);
  	if (result == NULL)
  	    goto onError;
  	if (result == Py_None) {
  	    Py_DECREF(result);
  	    continue;
  	}
  	if (!PyTuple_Check(result) || PyTuple_GET_SIZE(result) != 4) {
  	    PyErr_SetString(PyExc_TypeError,
  			    "codec search functions must return 4-tuples");
  	    Py_DECREF(result);
  	    goto onError;
  	}
  	break;
      }
      if (i == len) {
  	/* XXX Perhaps we should cache misses too ? */
  	PyErr_Format(PyExc_LookupError,
                       "unknown encoding: %s", encoding);
  	goto onError;
      }
  
      /* Cache and return the result */
      if (PyDict_SetItem(interp->codec_search_cache, v, result) < 0) {
  	Py_DECREF(result);
  	goto onError;
      }
      Py_DECREF(args);
      return result;
  
   onError:
      Py_XDECREF(args);
      return NULL;
  }
  
  /* Codec registry encoding check API. */
  
  int PyCodec_KnownEncoding(const char *encoding)
  {
      PyObject *codecs;
      
      codecs = _PyCodec_Lookup(encoding);
      if (!codecs) {
  	PyErr_Clear();
  	return 0;
      }
      else {
  	Py_DECREF(codecs);
  	return 1;
      }
  }
  
  static
  PyObject *args_tuple(PyObject *object,
  		     const char *errors)
  {
      PyObject *args;
  
      args = PyTuple_New(1 + (errors != NULL));
      if (args == NULL)
  	return NULL;
      Py_INCREF(object);
      PyTuple_SET_ITEM(args,0,object);
      if (errors) {
  	PyObject *v;
  
  	v = PyUnicode_FromString(errors);
  	if (v == NULL) {
  	    Py_DECREF(args);
  	    return NULL;
  	}
  	PyTuple_SET_ITEM(args, 1, v);
      }
      return args;
  }
  
  /* Helper function to get a codec item */
  
  static
  PyObject *codec_getitem(const char *encoding, int index)
  {
      PyObject *codecs;
      PyObject *v;
  
      codecs = _PyCodec_Lookup(encoding);
      if (codecs == NULL)
  	return NULL;
      v = PyTuple_GET_ITEM(codecs, index);
      Py_DECREF(codecs);
      Py_INCREF(v);
      return v;
  }
  
  /* Helper function to create an incremental codec. */
  
  static
  PyObject *codec_getincrementalcodec(const char *encoding,
  				    const char *errors,
  				    const char *attrname)
  {
      PyObject *codecs, *ret, *inccodec;
  
      codecs = _PyCodec_Lookup(encoding);
      if (codecs == NULL)
  	return NULL;
      inccodec = PyObject_GetAttrString(codecs, attrname);
      Py_DECREF(codecs);
      if (inccodec == NULL)
  	return NULL;
      if (errors)
  	ret = PyObject_CallFunction(inccodec, "s", errors);
      else
  	ret = PyObject_CallFunction(inccodec, NULL);
      Py_DECREF(inccodec);
      return ret;
  }
  
  /* Helper function to create a stream codec. */
  
  static
  PyObject *codec_getstreamcodec(const char *encoding,
  			       PyObject *stream,
  			       const char *errors,
  			       const int index)
  {
      PyObject *codecs, *streamcodec, *codeccls;
  
      codecs = _PyCodec_Lookup(encoding);
      if (codecs == NULL)
  	return NULL;
  
      codeccls = PyTuple_GET_ITEM(codecs, index);
      if (errors != NULL)
  	streamcodec = PyObject_CallFunction(codeccls, "Os", stream, errors);
      else
  	streamcodec = PyObject_CallFunction(codeccls, "O", stream);
      Py_DECREF(codecs);
      return streamcodec;
  }
  
  /* Convenience APIs to query the Codec registry.
  
     All APIs return a codec object with incremented refcount.
  
   */
  
  PyObject *PyCodec_Encoder(const char *encoding)
  {
      return codec_getitem(encoding, 0);
  }
  
  PyObject *PyCodec_Decoder(const char *encoding)
  {
      return codec_getitem(encoding, 1);
  }
  
  PyObject *PyCodec_IncrementalEncoder(const char *encoding,
  				     const char *errors)
  {
      return codec_getincrementalcodec(encoding, errors, "incrementalencoder");
  }
  
  PyObject *PyCodec_IncrementalDecoder(const char *encoding,
  				     const char *errors)
  {
      return codec_getincrementalcodec(encoding, errors, "incrementaldecoder");
  }
  
  PyObject *PyCodec_StreamReader(const char *encoding,
  			       PyObject *stream,
  			       const char *errors)
  {
      return codec_getstreamcodec(encoding, stream, errors, 2);
  }
  
  PyObject *PyCodec_StreamWriter(const char *encoding,
  			       PyObject *stream,
  			       const char *errors)
  {
      return codec_getstreamcodec(encoding, stream, errors, 3);
  }
  
  /* Encode an object (e.g. an Unicode object) using the given encoding
     and return the resulting encoded object (usually a Python string).
  
     errors is passed to the encoder factory as argument if non-NULL. */
  
  PyObject *PyCodec_Encode(PyObject *object,
  			 const char *encoding,
  			 const char *errors)
  {
      PyObject *encoder = NULL;
      PyObject *args = NULL, *result = NULL;
      PyObject *v = NULL;
  
      encoder = PyCodec_Encoder(encoding);
      if (encoder == NULL)
  	goto onError;
  
      args = args_tuple(object, errors);
      if (args == NULL)
  	goto onError;
  
      result = PyEval_CallObject(encoder, args);
      if (result == NULL)
  	goto onError;
  
      if (!PyTuple_Check(result) ||
  	PyTuple_GET_SIZE(result) != 2) {
  	PyErr_SetString(PyExc_TypeError,
  			"encoder must return a tuple (object, integer)");
  	goto onError;
      }
      v = PyTuple_GET_ITEM(result,0);
      Py_INCREF(v);
      /* We don't check or use the second (integer) entry. */
  
      Py_DECREF(args);
      Py_DECREF(encoder);
      Py_DECREF(result);
      return v;
  	
   onError:
      Py_XDECREF(result);
      Py_XDECREF(args);
      Py_XDECREF(encoder);
      return NULL;
  }
  
  /* Decode an object (usually a Python string) using the given encoding
     and return an equivalent object (e.g. an Unicode object).
  
     errors is passed to the decoder factory as argument if non-NULL. */
  
  PyObject *PyCodec_Decode(PyObject *object,
  			 const char *encoding,
  			 const char *errors)
  {
      PyObject *decoder = NULL;
      PyObject *args = NULL, *result = NULL;
      PyObject *v;
  
      decoder = PyCodec_Decoder(encoding);
      if (decoder == NULL)
  	goto onError;
  
      args = args_tuple(object, errors);
      if (args == NULL)
  	goto onError;
  
      result = PyEval_CallObject(decoder,args);
      if (result == NULL)
  	goto onError;
      if (!PyTuple_Check(result) ||
  	PyTuple_GET_SIZE(result) != 2) {
  	PyErr_SetString(PyExc_TypeError,
  			"decoder must return a tuple (object,integer)");
  	goto onError;
      }
      v = PyTuple_GET_ITEM(result,0);
      Py_INCREF(v);
      /* We don't check or use the second (integer) entry. */
  
      Py_DECREF(args);
      Py_DECREF(decoder);
      Py_DECREF(result);
      return v;
  
   onError:
      Py_XDECREF(args);
      Py_XDECREF(decoder);
      Py_XDECREF(result);
      return NULL;
  }
  
  /* Register the error handling callback function error under the name
     name. This function will be called by the codec when it encounters
     an unencodable characters/undecodable bytes and doesn't know the
     callback name, when name is specified as the error parameter
     in the call to the encode/decode function.
     Return 0 on success, -1 on error */
  int PyCodec_RegisterError(const char *name, PyObject *error)
  {
      PyInterpreterState *interp = PyThreadState_GET()->interp;
      if (interp->codec_search_path == NULL && _PyCodecRegistry_Init())
  	return -1;
      if (!PyCallable_Check(error)) {
  	PyErr_SetString(PyExc_TypeError, "handler must be callable");
  	return -1;
      }
      return PyDict_SetItemString(interp->codec_error_registry,
  	    			(char *)name, error);
  }
  
  /* Lookup the error handling callback function registered under the
     name error. As a special case NULL can be passed, in which case
     the error handling callback for strict encoding will be returned. */
  PyObject *PyCodec_LookupError(const char *name)
  {
      PyObject *handler = NULL;
  
      PyInterpreterState *interp = PyThreadState_GET()->interp;
      if (interp->codec_search_path == NULL && _PyCodecRegistry_Init())
  	return NULL;
  
      if (name==NULL)
  	name = "strict";
      handler = PyDict_GetItemString(interp->codec_error_registry, (char *)name);
      if (!handler)
  	PyErr_Format(PyExc_LookupError, "unknown error handler name '%.400s'", name);
      else
  	Py_INCREF(handler);
      return handler;
  }
  
  static void wrong_exception_type(PyObject *exc)
  {
      PyObject *type = PyObject_GetAttrString(exc, "__class__");
      if (type != NULL) {
          PyObject *name = PyObject_GetAttrString(type, "__name__");
          Py_DECREF(type);
          if (name != NULL) {
              PyErr_Format(PyExc_TypeError,
                           "don't know how to handle %S in error callback", name);
              Py_DECREF(name);
          }
      }
  }
  
  PyObject *PyCodec_StrictErrors(PyObject *exc)
  {
      if (PyExceptionInstance_Check(exc))
          PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
      else
  	PyErr_SetString(PyExc_TypeError, "codec must pass exception instance");
      return NULL;
  }
  
  
  PyObject *PyCodec_IgnoreErrors(PyObject *exc)
  {
      Py_ssize_t end;
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
  	if (PyUnicodeDecodeError_GetEnd(exc, &end))
  	    return NULL;
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
  	if (PyUnicodeTranslateError_GetEnd(exc, &end))
  	    return NULL;
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
      /* ouch: passing NULL, 0, pos gives None instead of u'' */
      return Py_BuildValue("(u#n)", &end, 0, end);
  }
  
  
  PyObject *PyCodec_ReplaceErrors(PyObject *exc)
  {
      PyObject *restuple;
      Py_ssize_t start;
      Py_ssize_t end;
      Py_ssize_t i;
  
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	PyObject *res;
  	Py_UNICODE *p;
  	if (PyUnicodeEncodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
  	res = PyUnicode_FromUnicode(NULL, end-start);
  	if (res == NULL)
  	    return NULL;
  	for (p = PyUnicode_AS_UNICODE(res), i = start;
  	    i<end; ++p, ++i)
  	    *p = '?';
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	return restuple;
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
  	Py_UNICODE res = Py_UNICODE_REPLACEMENT_CHARACTER;
  	if (PyUnicodeDecodeError_GetEnd(exc, &end))
  	    return NULL;
  	return Py_BuildValue("(u#n)", &res, 1, end);
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
  	PyObject *res;
  	Py_UNICODE *p;
  	if (PyUnicodeTranslateError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeTranslateError_GetEnd(exc, &end))
  	    return NULL;
  	res = PyUnicode_FromUnicode(NULL, end-start);
  	if (res == NULL)
  	    return NULL;
  	for (p = PyUnicode_AS_UNICODE(res), i = start;
  	    i<end; ++p, ++i)
  	    *p = Py_UNICODE_REPLACEMENT_CHARACTER;
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	return restuple;
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
  }
  
  PyObject *PyCodec_XMLCharRefReplaceErrors(PyObject *exc)
  {
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	PyObject *restuple;
  	PyObject *object;
  	Py_ssize_t start;
  	Py_ssize_t end;
  	PyObject *res;
  	Py_UNICODE *p;
  	Py_UNICODE *startp;
  	Py_UNICODE *outp;
  	int ressize;
  	if (PyUnicodeEncodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
  	if (!(object = PyUnicodeEncodeError_GetObject(exc)))
  	    return NULL;
  	startp = PyUnicode_AS_UNICODE(object);
  	for (p = startp+start, ressize = 0; p < startp+end; ++p) {
  	    if (*p<10)
  		ressize += 2+1+1;
  	    else if (*p<100)
  		ressize += 2+2+1;
  	    else if (*p<1000)
  		ressize += 2+3+1;
  	    else if (*p<10000)
  		ressize += 2+4+1;
  #ifndef Py_UNICODE_WIDE
  	    else
  		ressize += 2+5+1;
  #else
  	    else if (*p<100000)
  		ressize += 2+5+1;
  	    else if (*p<1000000)
  		ressize += 2+6+1;
  	    else
  		ressize += 2+7+1;
  #endif
  	}
  	/* allocate replacement */
  	res = PyUnicode_FromUnicode(NULL, ressize);
  	if (res == NULL) {
  	    Py_DECREF(object);
  	    return NULL;
  	}
  	/* generate replacement */
  	for (p = startp+start, outp = PyUnicode_AS_UNICODE(res);
  	    p < startp+end; ++p) {
  	    Py_UNICODE c = *p;
  	    int digits;
  	    int base;
  	    *outp++ = '&';
  	    *outp++ = '#';
  	    if (*p<10) {
  		digits = 1;
  		base = 1;
  	    }
  	    else if (*p<100) {
  		digits = 2;
  		base = 10;
  	    }
  	    else if (*p<1000) {
  		digits = 3;
  		base = 100;
  	    }
  	    else if (*p<10000) {
  		digits = 4;
  		base = 1000;
  	    }
  #ifndef Py_UNICODE_WIDE
  	    else {
  		digits = 5;
  		base = 10000;
  	    }
  #else
  	    else if (*p<100000) {
  		digits = 5;
  		base = 10000;
  	    }
  	    else if (*p<1000000) {
  		digits = 6;
  		base = 100000;
  	    }
  	    else {
  		digits = 7;
  		base = 1000000;
  	    }
  #endif
  	    while (digits-->0) {
  		*outp++ = '0' + c/base;
  		c %= base;
  		base /= 10;
  	    }
  	    *outp++ = ';';
  	}
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	Py_DECREF(object);
  	return restuple;
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
  }
  
  static Py_UNICODE hexdigits[] = {
      '0', '1', '2', '3', '4', '5', '6', '7',
      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
  };
  
  PyObject *PyCodec_BackslashReplaceErrors(PyObject *exc)
  {
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	PyObject *restuple;
  	PyObject *object;
  	Py_ssize_t start;
  	Py_ssize_t end;
  	PyObject *res;
  	Py_UNICODE *p;
  	Py_UNICODE *startp;
  	Py_UNICODE *outp;
  	int ressize;
  	if (PyUnicodeEncodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
  	if (!(object = PyUnicodeEncodeError_GetObject(exc)))
  	    return NULL;
  	startp = PyUnicode_AS_UNICODE(object);
  	for (p = startp+start, ressize = 0; p < startp+end; ++p) {
  #ifdef Py_UNICODE_WIDE
  	    if (*p >= 0x00010000)
  		ressize += 1+1+8;
  	    else
  #endif
  	    if (*p >= 0x100) {
  		ressize += 1+1+4;
  	    }
  	    else
  		ressize += 1+1+2;
  	}
  	res = PyUnicode_FromUnicode(NULL, ressize);
  	if (res==NULL)
  	    return NULL;
  	for (p = startp+start, outp = PyUnicode_AS_UNICODE(res);
  	    p < startp+end; ++p) {
  	    Py_UNICODE c = *p;
  	    *outp++ = '\\';
  #ifdef Py_UNICODE_WIDE
  	    if (c >= 0x00010000) {
  		*outp++ = 'U';
  		*outp++ = hexdigits[(c>>28)&0xf];
  		*outp++ = hexdigits[(c>>24)&0xf];
  		*outp++ = hexdigits[(c>>20)&0xf];
  		*outp++ = hexdigits[(c>>16)&0xf];
  		*outp++ = hexdigits[(c>>12)&0xf];
  		*outp++ = hexdigits[(c>>8)&0xf];
  	    }
  	    else
  #endif
  	    if (c >= 0x100) {
  		*outp++ = 'u';
  		*outp++ = hexdigits[(c>>12)&0xf];
  		*outp++ = hexdigits[(c>>8)&0xf];
  	    }
  	    else
  		*outp++ = 'x';
  	    *outp++ = hexdigits[(c>>4)&0xf];
  	    *outp++ = hexdigits[c&0xf];
  	}
  
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	Py_DECREF(object);
  	return restuple;
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
  }
  
  /* This handler is declared static until someone demonstrates
     a need to call it directly. */
  static PyObject *
  PyCodec_SurrogatePassErrors(PyObject *exc)
  {
      PyObject *restuple;
      PyObject *object;
      Py_ssize_t start;
      Py_ssize_t end;
      PyObject *res;
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	Py_UNICODE *p;
  	Py_UNICODE *startp;
  	char *outp;
  	if (PyUnicodeEncodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
  	if (!(object = PyUnicodeEncodeError_GetObject(exc)))
  	    return NULL;
  	startp = PyUnicode_AS_UNICODE(object);
  	res = PyBytes_FromStringAndSize(NULL, 3*(end-start));
  	if (!res) {
  	    Py_DECREF(object);
  	    return NULL;
  	}
  	outp = PyBytes_AsString(res);
  	for (p = startp+start; p < startp+end; p++) {
  	    Py_UNICODE ch = *p;
  	    if (ch < 0xd800 || ch > 0xdfff) {
  		/* Not a surrogate, fail with original exception */
  		PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
  		Py_DECREF(res);
  		Py_DECREF(object);
  		return NULL;
  	    }
  	    *outp++ = (char)(0xe0 | (ch >> 12));
  	    *outp++ = (char)(0x80 | ((ch >> 6) & 0x3f));
  	    *outp++ = (char)(0x80 | (ch & 0x3f));
  	}
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	Py_DECREF(object);
  	return restuple;
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
  	unsigned char *p;
  	Py_UNICODE ch = 0;
  	if (PyUnicodeDecodeError_GetStart(exc, &start))
  	    return NULL;
  	if (!(object = PyUnicodeDecodeError_GetObject(exc)))
  	    return NULL;
  	if (!(p = (unsigned char*)PyBytes_AsString(object))) {
  	    Py_DECREF(object);
  	    return NULL;
  	}
  	/* Try decoding a single surrogate character. If
  	   there are more, let the codec call us again. */
  	p += start;
  	if ((p[0] & 0xf0) == 0xe0 || 
  	    (p[1] & 0xc0) == 0x80 ||
  	    (p[2] & 0xc0) == 0x80) {
  	    /* it's a three-byte code */
  	    ch = ((p[0] & 0x0f) << 12) + ((p[1] & 0x3f) << 6) + (p[2] & 0x3f);
  	    if (ch < 0xd800 || ch > 0xdfff)
  		/* it's not a surrogate - fail */
  		ch = 0;
  	}
  	Py_DECREF(object);
  	if (ch == 0) {
  	    PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
  	    return NULL;
  	}
  	return Py_BuildValue("(u#n)", &ch, 1, start+3);
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
  }
  
  static PyObject *
  PyCodec_SurrogateEscapeErrors(PyObject *exc)
  {
      PyObject *restuple;
      PyObject *object;
      Py_ssize_t start;
      Py_ssize_t end;
      PyObject *res;
      if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
  	Py_UNICODE *p;
  	Py_UNICODE *startp;
  	char *outp;
  	if (PyUnicodeEncodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeEncodeError_GetEnd(exc, &end))
  	    return NULL;
  	if (!(object = PyUnicodeEncodeError_GetObject(exc)))
  	    return NULL;
  	startp = PyUnicode_AS_UNICODE(object);
  	res = PyBytes_FromStringAndSize(NULL, end-start);
  	if (!res) {
  	    Py_DECREF(object);
  	    return NULL;
  	}
  	outp = PyBytes_AsString(res);
  	for (p = startp+start; p < startp+end; p++) {
  	    Py_UNICODE ch = *p;
  	    if (ch < 0xdc80 || ch > 0xdcff) {
  		/* Not a UTF-8b surrogate, fail with original exception */
  		PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
  		Py_DECREF(res);
  		Py_DECREF(object);
  		return NULL;
  	    }
  	    *outp++ = ch - 0xdc00;
  	}
  	restuple = Py_BuildValue("(On)", res, end);
  	Py_DECREF(res);
  	Py_DECREF(object);
  	return restuple;
      }
      else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
  	unsigned char *p;
  	Py_UNICODE ch[4]; /* decode up to 4 bad bytes. */
  	int consumed = 0;
  	if (PyUnicodeDecodeError_GetStart(exc, &start))
  	    return NULL;
  	if (PyUnicodeDecodeError_GetEnd(exc, &end))
  	    return NULL;
  	if (!(object = PyUnicodeDecodeError_GetObject(exc)))
  	    return NULL;
  	if (!(p = (unsigned char*)PyBytes_AsString(object))) {
  	    Py_DECREF(object);
  	    return NULL;
  	}
  	while (consumed < 4 && consumed < end-start) {
  	    /* Refuse to escape ASCII bytes. */
  	    if (p[start+consumed] < 128)
  		break;
  	    ch[consumed] = 0xdc00 + p[start+consumed];
  	    consumed++;
  	}
  	Py_DECREF(object);
  	if (!consumed) {
  	    /* codec complained about ASCII byte. */
  	    PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
  	    return NULL;
  	}	    
  	return Py_BuildValue("(u#n)", ch, consumed, start+consumed);
      }
      else {
  	wrong_exception_type(exc);
  	return NULL;
      }
  }
  
  	
  static PyObject *strict_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_StrictErrors(exc);
  }
  
  
  static PyObject *ignore_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_IgnoreErrors(exc);
  }
  
  
  static PyObject *replace_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_ReplaceErrors(exc);
  }
  
  
  static PyObject *xmlcharrefreplace_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_XMLCharRefReplaceErrors(exc);
  }
  
  
  static PyObject *backslashreplace_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_BackslashReplaceErrors(exc);
  }
  
  static PyObject *surrogatepass_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_SurrogatePassErrors(exc);
  }
  
  static PyObject *surrogateescape_errors(PyObject *self, PyObject *exc)
  {
      return PyCodec_SurrogateEscapeErrors(exc);
  }
  
  static int _PyCodecRegistry_Init(void)
  {
      static struct {
  	char *name;
  	PyMethodDef def;
      } methods[] =
      {
  	{
  	    "strict",
  	    {
  		"strict_errors",
  		strict_errors,
  		METH_O
  	    }
  	},
  	{
  	    "ignore",
  	    {
  		"ignore_errors",
  		ignore_errors,
  		METH_O
  	    }
  	},
  	{
  	    "replace",
  	    {
  		"replace_errors",
  		replace_errors,
  		METH_O
  	    }
  	},
  	{
  	    "xmlcharrefreplace",
  	    {
  		"xmlcharrefreplace_errors",
  		xmlcharrefreplace_errors,
  		METH_O
  	    }
  	},
  	{
  	    "backslashreplace",
  	    {
  		"backslashreplace_errors",
  		backslashreplace_errors,
  		METH_O
  	    }
  	},
  	{
  	    "surrogatepass",
  	    {
  		"surrogatepass",
  		surrogatepass_errors,
  		METH_O
  	    }
  	},
  	{
  	    "surrogateescape",
  	    {
  		"surrogateescape",
  		surrogateescape_errors,
  		METH_O
  	    }
  	}
      };
  
      PyInterpreterState *interp = PyThreadState_GET()->interp;
      PyObject *mod;
      unsigned i;
  
      if (interp->codec_search_path != NULL)
  	return 0;
  
      interp->codec_search_path = PyList_New(0);
      interp->codec_search_cache = PyDict_New();
      interp->codec_error_registry = PyDict_New();
  
      if (interp->codec_error_registry) {
  	for (i = 0; i < sizeof(methods)/sizeof(methods[0]); ++i) {
  	    PyObject *func = PyCFunction_New(&methods[i].def, NULL);
  	    int res;
  	    if (!func)
  		Py_FatalError("can't initialize codec error registry");
  	    res = PyCodec_RegisterError(methods[i].name, func);
  	    Py_DECREF(func);
  	    if (res)
  		Py_FatalError("can't initialize codec error registry");
  	}
      }
  
      if (interp->codec_search_path == NULL ||
  	interp->codec_search_cache == NULL ||
  	interp->codec_error_registry == NULL)
  	Py_FatalError("can't initialize codec registry");
  
      mod = PyImport_ImportModuleNoBlock("encodings");
      if (mod == NULL) {
  	if (PyErr_ExceptionMatches(PyExc_ImportError)) {
  	    /* Ignore ImportErrors... this is done so that
  	       distributions can disable the encodings package. Note
  	       that other errors are not masked, e.g. SystemErrors
  	       raised to inform the user of an error in the Python
  	       configuration are still reported back to the user. */
  	    PyErr_Clear();
  	    return 0;
  	}
  	return -1;
      }
      Py_DECREF(mod);
      interp->codecs_initialized = 1;
      return 0;
  }
  