| /**************************************************************************** |
| * |
| * 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 (C) 2004-2022 by |
| * Albert Chin-A-Young. |
| * |
| * based on code in `src/gzip/ftgzip.c' |
| * |
| * 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 <freetype/internal/ftmemory.h> |
| #include <freetype/internal/ftstream.h> |
| #include <freetype/internal/ftdebug.h> |
| #include <freetype/ftlzw.h> |
| #include FT_CONFIG_STANDARD_LIBRARY_H |
| |
| |
| #include <freetype/ftmoderr.h> |
| |
| #undef FTERRORS_H_ |
| |
| #undef FT_ERR_PREFIX |
| #define FT_ERR_PREFIX LZW_Err_ |
| #define FT_ERR_BASE FT_Mod_Err_LZW |
| |
| #include <freetype/fterrors.h> |
| |
| |
| #ifdef FT_CONFIG_OPTION_USE_LZW |
| |
| #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 = FT_THROW( 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; |
| |
| |
| 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 = FT_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 = FT_THROW( 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 = FT_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 = FT_THROW( 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 unsigned long |
| ft_lzw_stream_io( FT_Stream stream, |
| unsigned long offset, |
| unsigned char* buffer, |
| unsigned long count ) |
| { |
| FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer; |
| |
| |
| return ft_lzw_file_io( zip, offset, buffer, count ); |
| } |
| |
| |
| FT_EXPORT_DEF( FT_Error ) |
| FT_Stream_OpenLZW( FT_Stream stream, |
| FT_Stream source ) |
| { |
| FT_Error error; |
| FT_Memory memory; |
| FT_LZWFile zip; |
| |
| |
| if ( !stream || !source ) |
| { |
| error = FT_THROW( Invalid_Stream_Handle ); |
| goto Exit; |
| } |
| |
| memory = source->memory; |
| |
| /* |
| * 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_QNEW( 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 = NULL; |
| 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 FT_THROW( Unimplemented_Feature ); |
| } |
| |
| |
| #endif /* !FT_CONFIG_OPTION_USE_LZW */ |
| |
| |
| /* END */ |