ref: 8a8c6022bff205c7e98d6bef30ccc78f8f1fd8e0
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, 2006 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 <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 */