misc/libfreetype/src/lzw/ftlzw.c
author koda
Sun, 29 Jan 2012 18:52:01 +0100
changeset 6613 c7bf3b7c49dd
parent 5172 88f2e05288ba
permissions -rw-r--r--
disabling the discovery of SDL13+ on desktop. SDL13 has become SDL2 with a completely different ABI and will require a new FindSDL2 module for Cmake to be found; for current sdl development installations, hedgewars will either use the compatibility layer (present in sdl1.3 but not in sdl2) or just fail to build (in case sdl2 is installed but sdl1.2.* is not). whew

/***************************************************************************/
/*                                                                         */
/*  ftlzw.c                                                                */
/*                                                                         */
/*    FreeType support for .Z compressed files.                            */
/*                                                                         */
/*  This optional component relies on NetBSD's zopen().  It should mainly  */
/*  be used to parse compressed PCF fonts, as found with many X11 server   */
/*  distributions.                                                         */
/*                                                                         */
/*  Copyright 2004, 2005, 2006, 2009, 2010 by                              */
/*  Albert Chin-A-Young.                                                   */
/*                                                                         */
/*  Based on code in src/gzip/ftgzip.c, Copyright 2004 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_LZW_H
#include FT_CONFIG_STANDARD_LIBRARY_H


#include FT_MODULE_ERRORS_H

#undef __FTERRORS_H__

#define FT_ERR_PREFIX  LZW_Err_
#define FT_ERR_BASE    FT_Mod_Err_LZW

#include FT_ERRORS_H


#ifdef FT_CONFIG_OPTION_USE_LZW

#ifdef FT_CONFIG_OPTION_PIC
#error "lzw code does not support PIC yet"
#endif 

#include "ftzopen.h"


/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****                  M E M O R Y   M A N A G E M E N T              *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****                   F I L E   D E S C R I P T O R                 *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

#define FT_LZW_BUFFER_SIZE  4096

  typedef struct  FT_LZWFileRec_
  {
    FT_Stream       source;         /* parent/source stream        */
    FT_Stream       stream;         /* embedding stream            */
    FT_Memory       memory;         /* memory allocator            */
    FT_LzwStateRec  lzw;            /* lzw decompressor state      */

    FT_Byte         buffer[FT_LZW_BUFFER_SIZE]; /* output buffer      */
    FT_ULong        pos;                        /* position in output */
    FT_Byte*        cursor;
    FT_Byte*        limit;

  } FT_LZWFileRec, *FT_LZWFile;


  /* check and skip .Z header */
  static FT_Error
  ft_lzw_check_header( FT_Stream  stream )
  {
    FT_Error  error;
    FT_Byte   head[2];


    if ( FT_STREAM_SEEK( 0 )       ||
         FT_STREAM_READ( head, 2 ) )
      goto Exit;

    /* head[0] && head[1] are the magic numbers */
    if ( head[0] != 0x1f ||
         head[1] != 0x9d )
      error = LZW_Err_Invalid_File_Format;

  Exit:
    return error;
  }


  static FT_Error
  ft_lzw_file_init( FT_LZWFile  zip,
                    FT_Stream   stream,
                    FT_Stream   source )
  {
    FT_LzwState  lzw   = &zip->lzw;
    FT_Error     error = LZW_Err_Ok;


    zip->stream = stream;
    zip->source = source;
    zip->memory = stream->memory;

    zip->limit  = zip->buffer + FT_LZW_BUFFER_SIZE;
    zip->cursor = zip->limit;
    zip->pos    = 0;

    /* check and skip .Z header */
    error = ft_lzw_check_header( source );
    if ( error )
      goto Exit;

    /* initialize internal lzw variable */
    ft_lzwstate_init( lzw, source );

  Exit:
    return error;
  }


  static void
  ft_lzw_file_done( FT_LZWFile  zip )
  {
    /* clear the rest */
    ft_lzwstate_done( &zip->lzw );

    zip->memory = NULL;
    zip->source = NULL;
    zip->stream = NULL;
  }


  static FT_Error
  ft_lzw_file_reset( FT_LZWFile  zip )
  {
    FT_Stream  stream = zip->source;
    FT_Error   error;


    if ( !FT_STREAM_SEEK( 0 ) )
    {
      ft_lzwstate_reset( &zip->lzw );

      zip->limit  = zip->buffer + FT_LZW_BUFFER_SIZE;
      zip->cursor = zip->limit;
      zip->pos    = 0;
    }

    return error;
  }


  static FT_Error
  ft_lzw_file_fill_output( FT_LZWFile  zip )
  {
    FT_LzwState  lzw = &zip->lzw;
    FT_ULong     count;
    FT_Error     error = LZW_Err_Ok;


    zip->cursor = zip->buffer;

    count = ft_lzwstate_io( lzw, zip->buffer, FT_LZW_BUFFER_SIZE );

    zip->limit = zip->cursor + count;

    if ( count == 0 )
      error = LZW_Err_Invalid_Stream_Operation;

    return error;
  }


  /* fill output buffer; `count' must be <= FT_LZW_BUFFER_SIZE */
  static FT_Error
  ft_lzw_file_skip_output( FT_LZWFile  zip,
                           FT_ULong    count )
  {
    FT_Error  error = LZW_Err_Ok;


    /* first, we skip what we can from the output buffer */
    {
      FT_ULong  delta = (FT_ULong)( zip->limit - zip->cursor );


      if ( delta >= count )
        delta = count;

      zip->cursor += delta;
      zip->pos    += delta;

      count -= delta;
    }

    /* next, we skip as many bytes remaining as possible */
    while ( count > 0 )
    {
      FT_ULong  delta = FT_LZW_BUFFER_SIZE;
      FT_ULong  numread;


      if ( delta > count )
        delta = count;

      numread = ft_lzwstate_io( &zip->lzw, NULL, delta );
      if ( numread < delta )
      {
        /* not enough bytes */
        error = LZW_Err_Invalid_Stream_Operation;
        break;
      }

      zip->pos += delta;
      count    -= delta;
    }

    return error;
  }


  static FT_ULong
  ft_lzw_file_io( FT_LZWFile  zip,
                  FT_ULong    pos,
                  FT_Byte*    buffer,
                  FT_ULong    count )
  {
    FT_ULong  result = 0;
    FT_Error  error;


    /* seeking backwards. */
    if ( pos < zip->pos )
    {
      /* If the new position is within the output buffer, simply       */
      /* decrement pointers, otherwise we reset the stream completely! */
      if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) )
      {
        zip->cursor -= zip->pos - pos;
        zip->pos     = pos;
      }
      else
      {
        error = ft_lzw_file_reset( zip );
        if ( error )
          goto Exit;
      }
    }

    /* skip unwanted bytes */
    if ( pos > zip->pos )
    {
      error = ft_lzw_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 + result, zip->cursor, delta );
      result      += delta;
      zip->cursor += delta;
      zip->pos    += delta;

      count -= delta;
      if ( count == 0 )
        break;

      error = ft_lzw_file_fill_output( zip );
      if ( error )
        break;
    }

  Exit:
    return result;
  }


/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****            L Z W   E M B E D D I N G   S T R E A M              *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

  static void
  ft_lzw_stream_close( FT_Stream  stream )
  {
    FT_LZWFile  zip    = (FT_LZWFile)stream->descriptor.pointer;
    FT_Memory   memory = stream->memory;


    if ( zip )
    {
      /* finalize lzw file descriptor */
      ft_lzw_file_done( zip );

      FT_FREE( zip );

      stream->descriptor.pointer = NULL;
    }
  }


  static FT_ULong
  ft_lzw_stream_io( FT_Stream  stream,
                    FT_ULong   pos,
                    FT_Byte*   buffer,
                    FT_ULong   count )
  {
    FT_LZWFile  zip = (FT_LZWFile)stream->descriptor.pointer;


    return ft_lzw_file_io( zip, pos, buffer, count );
  }


  FT_EXPORT_DEF( FT_Error )
  FT_Stream_OpenLZW( FT_Stream  stream,
                     FT_Stream  source )
  {
    FT_Error    error;
    FT_Memory   memory = source->memory;
    FT_LZWFile  zip;


    /*
     *  Check the header right now; this prevents allocation of a huge
     *  LZWFile object (400 KByte of heap memory) if not necessary.
     *
     *  Did I mention that you should never use .Z compressed font
     *  files?
     */
    error = ft_lzw_check_header( source );
    if ( error )
      goto Exit;

    FT_ZERO( stream );
    stream->memory = memory;

    if ( !FT_NEW( zip ) )
    {
      error = ft_lzw_file_init( zip, stream, source );
      if ( error )
      {
        FT_FREE( zip );
        goto Exit;
      }

      stream->descriptor.pointer = zip;
    }

    stream->size  = 0x7FFFFFFFL;  /* don't know the real size! */
    stream->pos   = 0;
    stream->base  = 0;
    stream->read  = ft_lzw_stream_io;
    stream->close = ft_lzw_stream_close;

  Exit:
    return error;
  }


#include "ftzopen.c"


#else  /* !FT_CONFIG_OPTION_USE_LZW */


  FT_EXPORT_DEF( FT_Error )
  FT_Stream_OpenLZW( FT_Stream  stream,
                     FT_Stream  source )
  {
    FT_UNUSED( stream );
    FT_UNUSED( source );

    return LZW_Err_Unimplemented_Feature;
  }


#endif /* !FT_CONFIG_OPTION_USE_LZW */


/* END */