1 /***************************************************************************/
5 /* FreeType support for .Z compressed files. */
7 /* This optional component relies on NetBSD's zopen(). It should mainly */
8 /* be used to parse compressed PCF fonts, as found with many X11 server */
11 /* Copyright 2004, 2005, 2006, 2009, 2010 by */
12 /* Albert Chin-A-Young. */
14 /* Based on code in src/gzip/ftgzip.c, Copyright 2004 by */
15 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
17 /* This file is part of the FreeType project, and may only be used, */
18 /* modified, and distributed under the terms of the FreeType project */
19 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
20 /* this file you indicate that you have read the license and */
21 /* understand and accept it fully. */
23 /***************************************************************************/
26 #include FT_INTERNAL_MEMORY_H
27 #include FT_INTERNAL_STREAM_H
28 #include FT_INTERNAL_DEBUG_H
30 #include FT_CONFIG_STANDARD_LIBRARY_H
33 #include FT_MODULE_ERRORS_H
37 #define FT_ERR_PREFIX LZW_Err_
38 #define FT_ERR_BASE FT_Mod_Err_LZW
43 #ifdef FT_CONFIG_OPTION_USE_LZW
45 #ifdef FT_CONFIG_OPTION_PIC
46 #error "lzw code does not support PIC yet"
52 /***************************************************************************/
53 /***************************************************************************/
55 /***** M E M O R Y M A N A G E M E N T *****/
57 /***************************************************************************/
58 /***************************************************************************/
60 /***************************************************************************/
61 /***************************************************************************/
63 /***** F I L E D E S C R I P T O R *****/
65 /***************************************************************************/
66 /***************************************************************************/
68 #define FT_LZW_BUFFER_SIZE 4096
70 typedef struct FT_LZWFileRec_
72 FT_Stream source; /* parent/source stream */
73 FT_Stream stream; /* embedding stream */
74 FT_Memory memory; /* memory allocator */
75 FT_LzwStateRec lzw; /* lzw decompressor state */
77 FT_Byte buffer[FT_LZW_BUFFER_SIZE]; /* output buffer */
78 FT_ULong pos; /* position in output */
82 } FT_LZWFileRec, *FT_LZWFile;
85 /* check and skip .Z header */
87 ft_lzw_check_header( FT_Stream stream )
93 if ( FT_STREAM_SEEK( 0 ) ||
94 FT_STREAM_READ( head, 2 ) )
97 /* head[0] && head[1] are the magic numbers */
98 if ( head[0] != 0x1f ||
100 error = LZW_Err_Invalid_File_Format;
108 ft_lzw_file_init( FT_LZWFile zip,
112 FT_LzwState lzw = &zip->lzw;
113 FT_Error error = LZW_Err_Ok;
116 zip->stream = stream;
117 zip->source = source;
118 zip->memory = stream->memory;
120 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE;
121 zip->cursor = zip->limit;
124 /* check and skip .Z header */
125 error = ft_lzw_check_header( source );
129 /* initialize internal lzw variable */
130 ft_lzwstate_init( lzw, source );
138 ft_lzw_file_done( FT_LZWFile zip )
141 ft_lzwstate_done( &zip->lzw );
150 ft_lzw_file_reset( FT_LZWFile zip )
152 FT_Stream stream = zip->source;
156 if ( !FT_STREAM_SEEK( 0 ) )
158 ft_lzwstate_reset( &zip->lzw );
160 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE;
161 zip->cursor = zip->limit;
170 ft_lzw_file_fill_output( FT_LZWFile zip )
172 FT_LzwState lzw = &zip->lzw;
174 FT_Error error = LZW_Err_Ok;
177 zip->cursor = zip->buffer;
179 count = ft_lzwstate_io( lzw, zip->buffer, FT_LZW_BUFFER_SIZE );
181 zip->limit = zip->cursor + count;
184 error = LZW_Err_Invalid_Stream_Operation;
190 /* fill output buffer; `count' must be <= FT_LZW_BUFFER_SIZE */
192 ft_lzw_file_skip_output( FT_LZWFile zip,
195 FT_Error error = LZW_Err_Ok;
198 /* first, we skip what we can from the output buffer */
200 FT_ULong delta = (FT_ULong)( zip->limit - zip->cursor );
203 if ( delta >= count )
206 zip->cursor += delta;
212 /* next, we skip as many bytes remaining as possible */
215 FT_ULong delta = FT_LZW_BUFFER_SIZE;
222 numread = ft_lzwstate_io( &zip->lzw, NULL, delta );
223 if ( numread < delta )
225 /* not enough bytes */
226 error = LZW_Err_Invalid_Stream_Operation;
239 ft_lzw_file_io( FT_LZWFile zip,
248 /* seeking backwards. */
249 if ( pos < zip->pos )
251 /* If the new position is within the output buffer, simply */
252 /* decrement pointers, otherwise we reset the stream completely! */
253 if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) )
255 zip->cursor -= zip->pos - pos;
260 error = ft_lzw_file_reset( zip );
266 /* skip unwanted bytes */
267 if ( pos > zip->pos )
269 error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
277 /* now read the data */
283 delta = (FT_ULong)( zip->limit - zip->cursor );
284 if ( delta >= count )
287 FT_MEM_COPY( buffer + result, zip->cursor, delta );
289 zip->cursor += delta;
296 error = ft_lzw_file_fill_output( zip );
306 /***************************************************************************/
307 /***************************************************************************/
309 /***** L Z W E M B E D D I N G S T R E A M *****/
311 /***************************************************************************/
312 /***************************************************************************/
315 ft_lzw_stream_close( FT_Stream stream )
317 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer;
318 FT_Memory memory = stream->memory;
323 /* finalize lzw file descriptor */
324 ft_lzw_file_done( zip );
328 stream->descriptor.pointer = NULL;
334 ft_lzw_stream_io( FT_Stream stream,
339 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer;
342 return ft_lzw_file_io( zip, pos, buffer, count );
346 FT_EXPORT_DEF( FT_Error )
347 FT_Stream_OpenLZW( FT_Stream stream,
351 FT_Memory memory = source->memory;
356 * Check the header right now; this prevents allocation of a huge
357 * LZWFile object (400 KByte of heap memory) if not necessary.
359 * Did I mention that you should never use .Z compressed font
362 error = ft_lzw_check_header( source );
367 stream->memory = memory;
369 if ( !FT_NEW( zip ) )
371 error = ft_lzw_file_init( zip, stream, source );
378 stream->descriptor.pointer = zip;
381 stream->size = 0x7FFFFFFFL; /* don't know the real size! */
384 stream->read = ft_lzw_stream_io;
385 stream->close = ft_lzw_stream_close;
395 #else /* !FT_CONFIG_OPTION_USE_LZW */
398 FT_EXPORT_DEF( FT_Error )
399 FT_Stream_OpenLZW( FT_Stream stream,
405 return LZW_Err_Unimplemented_Feature;
409 #endif /* !FT_CONFIG_OPTION_USE_LZW */