text: /***************************************************************************/
  /*                                                                         */
  /*  ftgzip.c                                                               */
  /*                                                                         */
  /*    FreeType support for .gz compressed files.                           */
  /*                                                                         */
  /*  This optional component relies on zlib.  It should mainly be used to   */
  /*  parse compressed PCF fonts, as found with many X11 server              */
  /*  distributions.                                                         */
  /*                                                                         */
  /*  Copyright 2002-2006, 2009-2013 by                                      */
  /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
  /*                                                                         */
  /*  This file is part of the FreeType project, and may only be used,       */
  /*  modified, and distributed under the terms of the FreeType project      */
  /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  /*  this file you indicate that you have read the license and              */
  /*  understand and accept it fully.                                        */
  /*                                                                         */
  /***************************************************************************/
  
  
  #include <ft2build.h>
  #include FT_INTERNAL_MEMORY_H
  #include FT_INTERNAL_STREAM_H
  #include FT_INTERNAL_DEBUG_H
  #include FT_GZIP_H
  #include FT_CONFIG_STANDARD_LIBRARY_H
  
  
  #include FT_MODULE_ERRORS_H
  
  #undef __FTERRORS_H__
  
  #undef  FT_ERR_PREFIX
  #define FT_ERR_PREFIX  Gzip_Err_
  #define FT_ERR_BASE    FT_Mod_Err_Gzip
  
  #include FT_ERRORS_H
  
  
  #ifdef FT_CONFIG_OPTION_USE_ZLIB
  
  #ifdef FT_CONFIG_OPTION_PIC
  #error "gzip code does not support PIC yet"
  #endif
  
  #ifdef FT_CONFIG_OPTION_SYSTEM_ZLIB
  
  #include <zlib.h>
  
  #else /* !FT_CONFIG_OPTION_SYSTEM_ZLIB */
  
   /* In this case, we include our own modified sources of the ZLib    */
   /* within the "ftgzip" component.  The modifications were necessary */
   /* to #include all files without conflicts, as well as preventing   */
   /* the definition of "extern" functions that may cause linking      */
   /* conflicts when a program is linked with both FreeType and the    */
   /* original ZLib.                                                   */
  
  #define NO_DUMMY_DECL
  #ifndef USE_ZLIB_ZCALLOC
  #define MY_ZCALLOC /* prevent all zcalloc() & zfree() in zutils.c */
  #endif
  
  #include "zlib.h"
  
  #undef  SLOW
  #define SLOW  1  /* we can't use asm-optimized sources here! */
  
  #if defined( _MSC_VER )      /* Visual C++ (and Intel C++)   */
    /* We disable the warning `conversion from XXX to YYY,     */
    /* possible loss of data' in order to compile cleanly with */
    /* the maximum level of warnings: zlib is non-FreeType     */
    /* code.                                                   */
  #pragma warning( push )
  #pragma warning( disable : 4244 )
  #endif /* _MSC_VER */
  
    /* Urgh.  `inflate_mask' must not be declared twice -- C++ doesn't like
       this.  We temporarily disable it and load all necessary header files. */
  #define NO_INFLATE_MASK
  #include "zutil.h"
  #include "inftrees.h"
  #include "infblock.h"
  #include "infcodes.h"
  #include "infutil.h"
  #undef  NO_INFLATE_MASK
  
    /* infutil.c must be included before infcodes.c */
  #include "zutil.c"
  #include "inftrees.c"
  #include "infutil.c"
  #include "infcodes.c"
  #include "infblock.c"
  #include "inflate.c"
  #include "adler32.c"
  
  #if defined( _MSC_VER )
  #pragma warning( pop )
  #endif
  
  #endif /* !FT_CONFIG_OPTION_SYSTEM_ZLIB */
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****            Z L I B   M E M O R Y   M A N A G E M E N T          *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
    /* it is better to use FreeType memory routines instead of raw
       'malloc/free' */
  
    static voidpf
    ft_gzip_alloc( FT_Memory  memory,
                   uInt       items,
                   uInt       size )
    {
      FT_ULong    sz = (FT_ULong)size * items;
      FT_Error    error;
      FT_Pointer  p  = NULL;
  
  
      (void)FT_ALLOC( p, sz );
      return p;
    }
  
  
    static void
    ft_gzip_free( FT_Memory  memory,
                  voidpf     address )
    {
      FT_MEM_FREE( address );
    }
  
  
  #if !defined( FT_CONFIG_OPTION_SYSTEM_ZLIB ) && !defined( USE_ZLIB_ZCALLOC )
  
    local voidpf
    zcalloc ( voidpf    opaque,
              unsigned  items,
              unsigned  size )
    {
      return ft_gzip_alloc( (FT_Memory)opaque, items, size );
    }
  
    local void
    zcfree( voidpf  opaque,
            voidpf  ptr )
    {
      ft_gzip_free( (FT_Memory)opaque, ptr );
    }
  
  #endif /* !SYSTEM_ZLIB && !USE_ZLIB_ZCALLOC */
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****               Z L I B   F I L E   D E S C R I P T O R           *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
  #define FT_GZIP_BUFFER_SIZE  4096
  
    typedef struct  FT_GZipFileRec_
    {
      FT_Stream  source;         /* parent/source stream        */
      FT_Stream  stream;         /* embedding stream            */
      FT_Memory  memory;         /* memory allocator            */
      z_stream   zstream;        /* zlib input stream           */
  
      FT_ULong   start;          /* starting position, after .gz header */
      FT_Byte    input[FT_GZIP_BUFFER_SIZE];   /* input read buffer  */
  
      FT_Byte    buffer[FT_GZIP_BUFFER_SIZE];  /* output buffer      */
      FT_ULong   pos;                          /* position in output */
      FT_Byte*   cursor;
      FT_Byte*   limit;
  
    } FT_GZipFileRec, *FT_GZipFile;
  
  
    /* gzip flag byte */
  #define FT_GZIP_ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
  #define FT_GZIP_HEAD_CRC     0x02 /* bit 1 set: header CRC present */
  #define FT_GZIP_EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
  #define FT_GZIP_ORIG_NAME    0x08 /* bit 3 set: original file name present */
  #define FT_GZIP_COMMENT      0x10 /* bit 4 set: file comment present */
  #define FT_GZIP_RESERVED     0xE0 /* bits 5..7: reserved */
  
  
    /* check and skip .gz header - we don't support `transparent' compression */
    static FT_Error
    ft_gzip_check_header( FT_Stream  stream )
    {
      FT_Error  error;
      FT_Byte   head[4];
  
  
      if ( FT_STREAM_SEEK( 0 )       ||
           FT_STREAM_READ( head, 4 ) )
        goto Exit;
  
      /* head[0] && head[1] are the magic numbers;    */
      /* head[2] is the method, and head[3] the flags */
      if ( head[0] != 0x1f              ||
           head[1] != 0x8b              ||
           head[2] != Z_DEFLATED        ||
          (head[3] & FT_GZIP_RESERVED)  )
      {
        error = FT_THROW( Invalid_File_Format );
        goto Exit;
      }
  
      /* skip time, xflags and os code */
      (void)FT_STREAM_SKIP( 6 );
  
      /* skip the extra field */
      if ( head[3] & FT_GZIP_EXTRA_FIELD )
      {
        FT_UInt  len;
  
  
        if ( FT_READ_USHORT_LE( len ) ||
             FT_STREAM_SKIP( len )    )
          goto Exit;
      }
  
      /* skip original file name */
      if ( head[3] & FT_GZIP_ORIG_NAME )
        for (;;)
        {
          FT_UInt  c;
  
  
          if ( FT_READ_BYTE( c ) )
            goto Exit;
  
          if ( c == 0 )
            break;
        }
  
      /* skip .gz comment */
      if ( head[3] & FT_GZIP_COMMENT )
        for (;;)
        {
          FT_UInt  c;
  
  
          if ( FT_READ_BYTE( c ) )
            goto Exit;
  
          if ( c == 0 )
            break;
        }
  
      /* skip CRC */
      if ( head[3] & FT_GZIP_HEAD_CRC )
        if ( FT_STREAM_SKIP( 2 ) )
          goto Exit;
  
    Exit:
      return error;
    }
  
  
    static FT_Error
    ft_gzip_file_init( FT_GZipFile  zip,
                       FT_Stream    stream,
                       FT_Stream    source )
    {
      z_stream*  zstream = &zip->zstream;
      FT_Error   error   = FT_Err_Ok;
  
  
      zip->stream = stream;
      zip->source = source;
      zip->memory = stream->memory;
  
      zip->limit  = zip->buffer + FT_GZIP_BUFFER_SIZE;
      zip->cursor = zip->limit;
      zip->pos    = 0;
  
      /* check and skip .gz header */
      {
        stream = source;
  
        error = ft_gzip_check_header( stream );
        if ( error )
          goto Exit;
  
        zip->start = FT_STREAM_POS();
      }
  
      /* initialize zlib -- there is no zlib header in the compressed stream */
      zstream->zalloc = (alloc_func)ft_gzip_alloc;
      zstream->zfree  = (free_func) ft_gzip_free;
      zstream->opaque = stream->memory;
  
      zstream->avail_in = 0;
      zstream->next_in  = zip->buffer;
  
      if ( inflateInit2( zstream, -MAX_WBITS ) != Z_OK ||
           zstream->next_in == NULL                     )
        error = FT_THROW( Invalid_File_Format );
  
    Exit:
      return error;
    }
  
  
    static void
    ft_gzip_file_done( FT_GZipFile  zip )
    {
      z_stream*  zstream = &zip->zstream;
  
  
      inflateEnd( zstream );
  
      /* clear the rest */
      zstream->zalloc    = NULL;
      zstream->zfree     = NULL;
      zstream->opaque    = NULL;
      zstream->next_in   = NULL;
      zstream->next_out  = NULL;
      zstream->avail_in  = 0;
      zstream->avail_out = 0;
  
      zip->memory = NULL;
      zip->source = NULL;
      zip->stream = NULL;
    }
  
  
    static FT_Error
    ft_gzip_file_reset( FT_GZipFile  zip )
    {
      FT_Stream  stream = zip->source;
      FT_Error   error;
  
  
      if ( !FT_STREAM_SEEK( zip->start ) )
      {
        z_stream*  zstream = &zip->zstream;
  
  
        inflateReset( zstream );
  
        zstream->avail_in  = 0;
        zstream->next_in   = zip->input;
        zstream->avail_out = 0;
        zstream->next_out  = zip->buffer;
  
        zip->limit  = zip->buffer + FT_GZIP_BUFFER_SIZE;
        zip->cursor = zip->limit;
        zip->pos    = 0;
      }
  
      return error;
    }
  
  
    static FT_Error
    ft_gzip_file_fill_input( FT_GZipFile  zip )
    {
      z_stream*  zstream = &zip->zstream;
      FT_Stream  stream  = zip->source;
      FT_ULong   size;
  
  
      if ( stream->read )
      {
        size = stream->read( stream, stream->pos, zip->input,
                             FT_GZIP_BUFFER_SIZE );
        if ( size == 0 )
          return FT_THROW( Invalid_Stream_Operation );
      }
      else
      {
        size = stream->size - stream->pos;
        if ( size > FT_GZIP_BUFFER_SIZE )
          size = FT_GZIP_BUFFER_SIZE;
  
        if ( size == 0 )
          return FT_THROW( Invalid_Stream_Operation );
  
        FT_MEM_COPY( zip->input, stream->base + stream->pos, size );
      }
      stream->pos += size;
  
      zstream->next_in  = zip->input;
      zstream->avail_in = size;
  
      return FT_Err_Ok;
    }
  
  
    static FT_Error
    ft_gzip_file_fill_output( FT_GZipFile  zip )
    {
      z_stream*  zstream = &zip->zstream;
      FT_Error   error   = FT_Err_Ok;
  
  
      zip->cursor        = zip->buffer;
      zstream->next_out  = zip->cursor;
      zstream->avail_out = FT_GZIP_BUFFER_SIZE;
  
      while ( zstream->avail_out > 0 )
      {
        int  err;
  
  
        if ( zstream->avail_in == 0 )
        {
          error = ft_gzip_file_fill_input( zip );
          if ( error )
            break;
        }
  
        err = inflate( zstream, Z_NO_FLUSH );
  
        if ( err == Z_STREAM_END )
        {
          zip->limit = zstream->next_out;
          if ( zip->limit == zip->cursor )
            error = FT_THROW( Invalid_Stream_Operation );
          break;
        }
        else if ( err != Z_OK )
        {
          error = FT_THROW( Invalid_Stream_Operation );
          break;
        }
      }
  
      return error;
    }
  
  
    /* fill output buffer; `count' must be <= FT_GZIP_BUFFER_SIZE */
    static FT_Error
    ft_gzip_file_skip_output( FT_GZipFile  zip,
                              FT_ULong     count )
    {
      FT_Error  error = FT_Err_Ok;
      FT_ULong  delta;
  
  
      for (;;)
      {
        delta = (FT_ULong)( zip->limit - zip->cursor );
        if ( delta >= count )
          delta = count;
  
        zip->cursor += delta;
        zip->pos    += delta;
  
        count -= delta;
        if ( count == 0 )
          break;
  
        error = ft_gzip_file_fill_output( zip );
        if ( error )
          break;
      }
  
      return error;
    }
  
  
    static FT_ULong
    ft_gzip_file_io( FT_GZipFile  zip,
                     FT_ULong     pos,
                     FT_Byte*     buffer,
                     FT_ULong     count )
    {
      FT_ULong  result = 0;
      FT_Error  error;
  
  
      /* Reset inflate stream if we're seeking backwards.        */
      /* Yes, that is not too efficient, but it saves memory :-) */
      if ( pos < zip->pos )
      {
        error = ft_gzip_file_reset( zip );
        if ( error )
          goto Exit;
      }
  
      /* skip unwanted bytes */
      if ( pos > zip->pos )
      {
        error = ft_gzip_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
        if ( error )
          goto Exit;
      }
  
      if ( count == 0 )
        goto Exit;
  
      /* now read the data */
      for (;;)
      {
        FT_ULong  delta;
  
  
        delta = (FT_ULong)( zip->limit - zip->cursor );
        if ( delta >= count )
          delta = count;
  
        FT_MEM_COPY( buffer, zip->cursor, delta );
        buffer      += delta;
        result      += delta;
        zip->cursor += delta;
        zip->pos    += delta;
  
        count -= delta;
        if ( count == 0 )
          break;
  
        error = ft_gzip_file_fill_output( zip );
        if ( error )
          break;
      }
  
    Exit:
      return result;
    }
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****               G Z   E M B E D D I N G   S T R E A M             *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
    static void
    ft_gzip_stream_close( FT_Stream  stream )
    {
      FT_GZipFile  zip    = (FT_GZipFile)stream->descriptor.pointer;
      FT_Memory    memory = stream->memory;
  
  
      if ( zip )
      {
        /* finalize gzip file descriptor */
        ft_gzip_file_done( zip );
  
        FT_FREE( zip );
  
        stream->descriptor.pointer = NULL;
      }
    }
  
  
    static FT_ULong
    ft_gzip_stream_io( FT_Stream  stream,
                       FT_ULong   pos,
                       FT_Byte*   buffer,
                       FT_ULong   count )
    {
      FT_GZipFile  zip = (FT_GZipFile)stream->descriptor.pointer;
  
  
      return ft_gzip_file_io( zip, pos, buffer, count );
    }
  
  
    static FT_ULong
    ft_gzip_get_uncompressed_size( FT_Stream  stream )
    {
      FT_Error  error;
      FT_ULong  old_pos;
      FT_ULong  result = 0;
  
  
      old_pos = stream->pos;
      if ( !FT_Stream_Seek( stream, stream->size - 4 ) )
      {
        result = FT_Stream_ReadULong( stream, &error );
        if ( error )
          result = 0;
  
        (void)FT_Stream_Seek( stream, old_pos );
      }
  
      return result;
    }
  
  
    FT_EXPORT_DEF( FT_Error )
    FT_Stream_OpenGzip( FT_Stream  stream,
                        FT_Stream  source )
    {
      FT_Error     error;
      FT_Memory    memory = source->memory;
      FT_GZipFile  zip = NULL;
  
  
      /*
       *  check the header right now; this prevents allocating un-necessary
       *  objects when we don't need them
       */
      error = ft_gzip_check_header( source );
      if ( error )
        goto Exit;
  
      FT_ZERO( stream );
      stream->memory = memory;
  
      if ( !FT_QNEW( zip ) )
      {
        error = ft_gzip_file_init( zip, stream, source );
        if ( error )
        {
          FT_FREE( zip );
          goto Exit;
        }
  
        stream->descriptor.pointer = zip;
      }
  
      /*
       *  We use the following trick to try to dramatically improve the
       *  performance while dealing with small files.  If the original stream
       *  size is less than a certain threshold, we try to load the whole font
       *  file into memory.  This saves us from using the 32KB buffer needed
       *  to inflate the file, plus the two 4KB intermediate input/output
       *  buffers used in the `FT_GZipFile' structure.
       */
      {
        FT_ULong  zip_size = ft_gzip_get_uncompressed_size( source );
  
  
        if ( zip_size != 0 && zip_size < 40 * 1024 )
        {
          FT_Byte*  zip_buff = NULL;
  
  
          if ( !FT_ALLOC( zip_buff, zip_size ) )
          {
            FT_ULong  count;
  
  
            count = ft_gzip_file_io( zip, 0, zip_buff, zip_size );
            if ( count == zip_size )
            {
              ft_gzip_file_done( zip );
              FT_FREE( zip );
  
              stream->descriptor.pointer = NULL;
  
              stream->size  = zip_size;
              stream->pos   = 0;
              stream->base  = zip_buff;
              stream->read  = NULL;
              stream->close = ft_gzip_stream_close;
  
              goto Exit;
            }
  
            ft_gzip_file_io( zip, 0, NULL, 0 );
            FT_FREE( zip_buff );
          }
          error = FT_Err_Ok;
        }
      }
  
      stream->size  = 0x7FFFFFFFL;  /* don't know the real size! */
      stream->pos   = 0;
      stream->base  = 0;
      stream->read  = ft_gzip_stream_io;
      stream->close = ft_gzip_stream_close;
  
    Exit:
      return error;
    }
  
  #else  /* !FT_CONFIG_OPTION_USE_ZLIB */
  
    FT_EXPORT_DEF( FT_Error )
    FT_Stream_OpenGzip( FT_Stream  stream,
                        FT_Stream  source )
    {
      FT_UNUSED( stream );
      FT_UNUSED( source );
  
      return FT_THROW( Unimplemented_Feature );
    }
  
  #endif /* !FT_CONFIG_OPTION_USE_ZLIB */
  
  
  /* END */
  