421 lines
11 KiB
C
421 lines
11 KiB
C
/***************************************************************************/
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/* */
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/* ftlzw.c */
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/* */
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/* FreeType support for .Z compressed files. */
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/* */
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/* This optional component relies on NetBSD's zopen(). It should mainly */
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/* be used to parse compressed PCF fonts, as found with many X11 server */
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/* distributions. */
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/* */
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/* Copyright 2004-2016 by */
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/* Albert Chin-A-Young. */
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/* */
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/* based on code in `src/gzip/ftgzip.c' */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#include <ft2build.h>
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#include FT_INTERNAL_MEMORY_H
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#include FT_INTERNAL_STREAM_H
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#include FT_INTERNAL_DEBUG_H
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#include FT_LZW_H
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#include FT_CONFIG_STANDARD_LIBRARY_H
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#include FT_MODULE_ERRORS_H
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#undef FTERRORS_H_
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#undef FT_ERR_PREFIX
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#define FT_ERR_PREFIX LZW_Err_
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#define FT_ERR_BASE FT_Mod_Err_LZW
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#include FT_ERRORS_H
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#ifdef FT_CONFIG_OPTION_USE_LZW
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#ifdef FT_CONFIG_OPTION_PIC
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#error "lzw code does not support PIC yet"
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#endif
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#include "ftzopen.h"
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/***************************************************************************/
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/***************************************************************************/
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/***** *****/
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/***** M E M O R Y M A N A G E M E N T *****/
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/***** *****/
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/***************************************************************************/
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/***************************************************************************/
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/***************************************************************************/
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/***************************************************************************/
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/***** *****/
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/***** F I L E D E S C R I P T O R *****/
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/***** *****/
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/***************************************************************************/
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/***************************************************************************/
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#define FT_LZW_BUFFER_SIZE 4096
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typedef struct FT_LZWFileRec_
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{
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FT_Stream source; /* parent/source stream */
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FT_Stream stream; /* embedding stream */
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FT_Memory memory; /* memory allocator */
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FT_LzwStateRec lzw; /* lzw decompressor state */
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FT_Byte buffer[FT_LZW_BUFFER_SIZE]; /* output buffer */
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FT_ULong pos; /* position in output */
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FT_Byte* cursor;
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FT_Byte* limit;
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} FT_LZWFileRec, *FT_LZWFile;
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/* check and skip .Z header */
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static FT_Error
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ft_lzw_check_header( FT_Stream stream )
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{
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FT_Error error;
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FT_Byte head[2];
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if ( FT_STREAM_SEEK( 0 ) ||
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FT_STREAM_READ( head, 2 ) )
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goto Exit;
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/* head[0] && head[1] are the magic numbers */
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if ( head[0] != 0x1F ||
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head[1] != 0x9D )
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error = FT_THROW( Invalid_File_Format );
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Exit:
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return error;
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}
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static FT_Error
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ft_lzw_file_init( FT_LZWFile zip,
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FT_Stream stream,
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FT_Stream source )
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{
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FT_LzwState lzw = &zip->lzw;
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FT_Error error;
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zip->stream = stream;
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zip->source = source;
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zip->memory = stream->memory;
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zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE;
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zip->cursor = zip->limit;
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zip->pos = 0;
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/* check and skip .Z header */
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error = ft_lzw_check_header( source );
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if ( error )
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goto Exit;
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/* initialize internal lzw variable */
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ft_lzwstate_init( lzw, source );
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Exit:
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return error;
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}
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static void
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ft_lzw_file_done( FT_LZWFile zip )
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{
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/* clear the rest */
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ft_lzwstate_done( &zip->lzw );
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zip->memory = NULL;
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zip->source = NULL;
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zip->stream = NULL;
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}
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static FT_Error
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ft_lzw_file_reset( FT_LZWFile zip )
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{
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FT_Stream stream = zip->source;
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FT_Error error;
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if ( !FT_STREAM_SEEK( 0 ) )
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{
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ft_lzwstate_reset( &zip->lzw );
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zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE;
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zip->cursor = zip->limit;
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zip->pos = 0;
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}
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return error;
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}
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static FT_Error
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ft_lzw_file_fill_output( FT_LZWFile zip )
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{
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FT_LzwState lzw = &zip->lzw;
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FT_ULong count;
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FT_Error error = FT_Err_Ok;
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zip->cursor = zip->buffer;
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count = ft_lzwstate_io( lzw, zip->buffer, FT_LZW_BUFFER_SIZE );
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zip->limit = zip->cursor + count;
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if ( count == 0 )
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error = FT_THROW( Invalid_Stream_Operation );
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return error;
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}
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/* fill output buffer; `count' must be <= FT_LZW_BUFFER_SIZE */
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static FT_Error
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ft_lzw_file_skip_output( FT_LZWFile zip,
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FT_ULong count )
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{
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FT_Error error = FT_Err_Ok;
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/* first, we skip what we can from the output buffer */
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{
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FT_ULong delta = (FT_ULong)( zip->limit - zip->cursor );
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if ( delta >= count )
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delta = count;
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zip->cursor += delta;
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zip->pos += delta;
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count -= delta;
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}
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/* next, we skip as many bytes remaining as possible */
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while ( count > 0 )
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{
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FT_ULong delta = FT_LZW_BUFFER_SIZE;
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FT_ULong numread;
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if ( delta > count )
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delta = count;
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numread = ft_lzwstate_io( &zip->lzw, NULL, delta );
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if ( numread < delta )
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{
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/* not enough bytes */
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error = FT_THROW( Invalid_Stream_Operation );
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break;
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}
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zip->pos += delta;
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count -= delta;
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}
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return error;
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}
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static FT_ULong
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ft_lzw_file_io( FT_LZWFile zip,
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FT_ULong pos,
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FT_Byte* buffer,
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FT_ULong count )
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{
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FT_ULong result = 0;
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FT_Error error;
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/* seeking backwards. */
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if ( pos < zip->pos )
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{
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/* If the new position is within the output buffer, simply */
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/* decrement pointers, otherwise we reset the stream completely! */
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if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) )
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{
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zip->cursor -= zip->pos - pos;
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zip->pos = pos;
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}
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else
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{
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error = ft_lzw_file_reset( zip );
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if ( error )
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goto Exit;
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}
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}
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/* skip unwanted bytes */
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if ( pos > zip->pos )
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{
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error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
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if ( error )
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goto Exit;
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}
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if ( count == 0 )
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goto Exit;
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/* now read the data */
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for (;;)
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{
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FT_ULong delta;
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delta = (FT_ULong)( zip->limit - zip->cursor );
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if ( delta >= count )
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delta = count;
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FT_MEM_COPY( buffer + result, zip->cursor, delta );
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result += delta;
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zip->cursor += delta;
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zip->pos += delta;
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count -= delta;
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if ( count == 0 )
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break;
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error = ft_lzw_file_fill_output( zip );
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if ( error )
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break;
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}
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Exit:
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return result;
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}
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/***************************************************************************/
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/***************************************************************************/
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/***** *****/
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/***** L Z W E M B E D D I N G S T R E A M *****/
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/***** *****/
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/***************************************************************************/
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/***************************************************************************/
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static void
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ft_lzw_stream_close( FT_Stream stream )
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{
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FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer;
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FT_Memory memory = stream->memory;
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if ( zip )
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{
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/* finalize lzw file descriptor */
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ft_lzw_file_done( zip );
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FT_FREE( zip );
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stream->descriptor.pointer = NULL;
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}
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}
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static unsigned long
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ft_lzw_stream_io( FT_Stream stream,
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unsigned long offset,
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unsigned char* buffer,
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unsigned long count )
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{
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FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer;
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return ft_lzw_file_io( zip, offset, buffer, count );
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}
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FT_EXPORT_DEF( FT_Error )
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FT_Stream_OpenLZW( FT_Stream stream,
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FT_Stream source )
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{
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FT_Error error;
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FT_Memory memory;
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FT_LZWFile zip = NULL;
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if ( !stream || !source )
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{
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error = FT_THROW( Invalid_Stream_Handle );
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goto Exit;
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}
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memory = source->memory;
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/*
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* Check the header right now; this prevents allocation of a huge
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* LZWFile object (400 KByte of heap memory) if not necessary.
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*
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* Did I mention that you should never use .Z compressed font
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* files?
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*/
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error = ft_lzw_check_header( source );
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if ( error )
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goto Exit;
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FT_ZERO( stream );
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stream->memory = memory;
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if ( !FT_NEW( zip ) )
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{
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error = ft_lzw_file_init( zip, stream, source );
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if ( error )
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{
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FT_FREE( zip );
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goto Exit;
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}
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stream->descriptor.pointer = zip;
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}
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stream->size = 0x7FFFFFFFL; /* don't know the real size! */
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stream->pos = 0;
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stream->base = 0;
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stream->read = ft_lzw_stream_io;
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stream->close = ft_lzw_stream_close;
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Exit:
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return error;
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}
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#include "ftzopen.c"
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#else /* !FT_CONFIG_OPTION_USE_LZW */
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FT_EXPORT_DEF( FT_Error )
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FT_Stream_OpenLZW( FT_Stream stream,
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FT_Stream source )
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{
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FT_UNUSED( stream );
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FT_UNUSED( source );
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return FT_THROW( Unimplemented_Feature );
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}
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#endif /* !FT_CONFIG_OPTION_USE_LZW */
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/* END */
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