ref: ea5b85629369679ffc003445f060a880fae9e61d
dir: /src/lzw/ftlzw.c/
/***************************************************************************/
/* */
/* 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 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 <string.h>
#include <stdio.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
#include "zopen.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 */
s_zstate_t zstream; /* lzw input stream */
FT_ULong start; /* starting position, after .Z header */
FT_Byte input[FT_LZW_BUFFER_SIZE]; /* input buffer */
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 )
{
s_zstate_t* zstream = &zip->zstream;
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 */
{
stream = source;
error = ft_lzw_check_header( source );
if ( error )
goto Exit;
zip->start = FT_STREAM_POS();
}
/* initialize internal lzw variable */
zinit( zstream );
zstream->avail_in = 0;
zstream->next_in = zip->buffer;
zstream->zs_in_count = source->size - 2;
if ( zstream->next_in == NULL )
error = LZW_Err_Invalid_File_Format;
Exit:
return error;
}
static void
ft_lzw_file_done( FT_LZWFile zip )
{
s_zstate_t* zstream = &zip->zstream;
/* clear the rest */
zstream->next_in = NULL;
zstream->next_out = NULL;
zstream->avail_in = 0;
zstream->avail_out = 0;
zstream->total_in = 0;
zstream->total_out = 0;
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( zip->start ) )
{
s_zstate_t* zstream = &zip->zstream;
zinit( zstream );
zstream->avail_in = 0;
zstream->next_in = zip->input;
zstream->total_in = 0;
zstream->avail_out = 0;
zstream->next_out = zip->buffer;
zstream->total_out = 0;
zstream->zs_in_count = zip->source->size - 2;
zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE;
zip->cursor = zip->limit;
zip->pos = 0;
}
return error;
}
static FT_Error
ft_lzw_file_fill_input( FT_LZWFile zip )
{
s_zstate_t* zstream = &zip->zstream;
FT_Stream stream = zip->source;
FT_ULong size;
if ( stream->read )
{
size = stream->read( stream, stream->pos, zip->input,
FT_LZW_BUFFER_SIZE );
if ( size == 0 )
return LZW_Err_Invalid_Stream_Operation;
}
else
{
size = stream->size - stream->pos;
if ( size > FT_LZW_BUFFER_SIZE )
size = FT_LZW_BUFFER_SIZE;
if ( size == 0 )
return LZW_Err_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 LZW_Err_Ok;
}
static FT_Error
ft_lzw_file_fill_output( FT_LZWFile zip )
{
s_zstate_t* zstream = &zip->zstream;
FT_Error error = 0;
zip->cursor = zip->buffer;
zstream->next_out = zip->cursor;
zstream->avail_out = FT_LZW_BUFFER_SIZE;
while ( zstream->avail_out > 0 )
{
int num_read = 0;
if ( zstream->avail_in == 0 )
{
error = ft_lzw_file_fill_input( zip );
if ( error )
break;
}
num_read = zread( zstream );
if ( num_read == -1 && zstream->zs_in_count == 0 )
{
zip->limit = zstream->next_out;
if ( zip->limit == zip->cursor )
error = LZW_Err_Invalid_Stream_Operation;
break;
}
else if ( num_read == -1 )
break;
else
zstream->avail_out -= num_read;
}
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;
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_lzw_file_fill_output( zip );
if ( error )
break;
}
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;
/* Teset inflate stream if we're seeking backwards. */
/* Yes, that is not too efficient, but it saves memory :-) */
if ( pos < zip->pos )
{
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, zip->cursor, delta );
buffer += 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 a huge
* LZWFile object (400 KByte of heap memory) if not necessary.
*
* Did I mention that you should never use .Z compressed font
* file?
*/
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 "zopen.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 */