diff options
Diffstat (limited to 'src/lzw/ftlzw.c')
| -rw-r--r-- | src/lzw/ftlzw.c | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/src/lzw/ftlzw.c b/src/lzw/ftlzw.c new file mode 100644 index 0000000..45fbf7b --- /dev/null +++ b/src/lzw/ftlzw.c @@ -0,0 +1,413 @@ +/***************************************************************************/ +/* */ +/* 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 "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 */ + { + stream = source; + + 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 = 0; + + + 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 */ |