* src/base/ftdbgmem.c: fixes to better account for memory reallocations

* src/lzw/ftlzw2.c, src/lzw/ftzopen.h, src/lzw/ftzopen.c, src/lzw/rules.mk:
    first version of LZW loader re-implementation. Apparently, saves about
    260 KB of heap memory when loading tir24.pcf.Z
This commit is contained in:
David Turner 2005-10-20 15:33:34 +00:00
parent 7e30776ee8
commit c1b6d08291
6 changed files with 1009 additions and 24 deletions

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@ -1,3 +1,11 @@
2005-10-20 David Turner <david@freetype.org>
* src/base/ftdbgmem.c: fixes to better account for memory reallocations
* src/lzw/ftlzw2.c, src/lzw/ftzopen.h, src/lzw/ftzopen.c, src/lzw/rules.mk:
first version of LZW loader re-implementation. Apparently, saves about
260 KB of heap memory when loading timR24.pcf.Z
2005-10-20 Chia-I Wu <b90201047@ntu.edu.tw>
* include/freetype/ftbitmap.h (FT_Bitmap_Copy, FT_Bitmap_Embolden),

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@ -493,7 +493,8 @@
static void
ft_mem_table_set( FT_MemTable table,
FT_Byte* address,
FT_ULong size )
FT_ULong size,
FT_Long delta )
{
FT_MemNode *pnode, node;
@ -536,19 +537,33 @@
node->address = address;
node->size = size;
node->source = source = ft_mem_table_get_source( table );
node->source = source = ft_mem_table_get_source( table );
source->all_blocks++;
source->cur_blocks++;
if ( source->cur_blocks > source->max_blocks )
source->max_blocks = source->cur_blocks;
if ( delta == 0 )
{
/* this is an allocation */
source->all_blocks++;
source->cur_blocks++;
if ( source->cur_blocks > source->max_blocks )
source->max_blocks = source->cur_blocks;
}
if ( size > (FT_ULong)source->cur_max )
source->cur_max = size;
if ( delta != 0 )
{
/* we're growing or shrinking a realloc-ed block */
source->cur_size += delta;
}
else
{
/* we're allocating a new block */
source->cur_size += size;
}
source->all_size += size;
source->cur_size += size;
if ( source->cur_size > source->max_size )
source->max_size = source->cur_size;
@ -560,8 +575,16 @@
pnode[0] = node;
table->nodes++;
table->alloc_total += size;
table->alloc_current += size;
if ( delta != 0 )
{
table->alloc_total += size;
table->alloc_current += delta;
}
else
{
table->alloc_total += size;
table->alloc_current += size;
}
if ( table->alloc_current > table->alloc_max )
table->alloc_max = table->alloc_current;
@ -574,7 +597,8 @@
static void
ft_mem_table_remove( FT_MemTable table,
FT_Byte* address )
FT_Byte* address,
FT_Long delta )
{
if ( table )
{
@ -599,12 +623,16 @@
/* scramble the node's content for additional safety */
FT_MEM_SET( address, 0xF3, node->size );
table->alloc_current -= node->size;
source = node->source;
if ( delta == 0 )
{
source = node->source;
source->cur_blocks--;
source->cur_size -= node->size;
source->cur_blocks--;
source->cur_size -= node->size;
table->alloc_current -= node->size;
}
if ( table->keep_alive )
{
@ -662,9 +690,11 @@
block = (FT_Byte *)ft_mem_table_alloc( table, size );
if ( block )
ft_mem_table_set( table, block, (FT_ULong)size );
{
ft_mem_table_set( table, block, (FT_ULong)size, 0 );
table->alloc_count++;
table->alloc_count++;
}
table->file_name = NULL;
table->line_no = 0;
@ -685,7 +715,7 @@
FT_FILENAME( table->file_name ),
table->line_no );
ft_mem_table_remove( table, (FT_Byte*)block );
ft_mem_table_remove( table, (FT_Byte*)block, 0 );
if ( !table->keep_alive )
ft_mem_table_free( table, block );
@ -706,6 +736,7 @@
FT_MemTable table = (FT_MemTable)memory->user;
FT_MemNode node, *pnode;
FT_Pointer new_block;
FT_Long delta;
const char* file_name = FT_FILENAME( table->file_name );
FT_Long line_no = table->line_no;
@ -743,6 +774,7 @@
"%ld instead of %ld in (%s:%ld)",
block, cur_size, node->size, file_name, line_no );
#if 0
new_block = ft_mem_debug_alloc( memory, new_size );
if ( new_block == NULL )
return NULL;
@ -754,6 +786,43 @@
ft_mem_debug_free( memory, (FT_Byte*)block );
#else
/* return NULL if the maximum number of allocations was reached */
if ( table->bound_count &&
table->alloc_count >= table->alloc_count_max )
return NULL;
delta = (FT_Long)( new_size - cur_size );
/* return NULL if this allocation would overflow the maximum heap size */
if ( delta > 0 &&
table->bound_total &&
table->alloc_current + (FT_ULong)delta > table->alloc_total_max )
return NULL;
new_block = (FT_Byte *)ft_mem_table_alloc( table, new_size );
if ( new_block == NULL )
return NULL;
ft_mem_table_set( table, new_block, new_size, delta );
table->file_name = NULL;
table->line_no = 0;
ft_memcpy( new_block, block, cur_size < new_size ? cur_size : new_size );
table->file_name = file_name;
table->line_no = line_no;
ft_mem_table_remove( table, (FT_Byte*)block, delta );
if ( !table->keep_alive )
ft_mem_table_free( table, block );
table->alloc_current += delta;
#endif
return new_block;
}

411
src/lzw/ftlzw2.c Normal file
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@ -0,0 +1,411 @@
/***************************************************************************/
/* */
/* 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 "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'll 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 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 "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 */

355
src/lzw/ftzopen.c Normal file
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@ -0,0 +1,355 @@
#include "ftzopen.h"
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_STREAM_H
#include FT_INTERNAL_DEBUG_H
/* refill input buffer, return 0 on success, or -1 if eof
*/
static int
ft_lzwstate_refill( FT_LzwState state )
{
int result = -1;
if ( !state->in_eof )
{
FT_ULong count = FT_Stream_TryRead( state->source,
state->in_buff,
sizeof( state->in_buff ) );
state->in_cursor = state->in_buff;
state->in_limit = state->in_buff + count;
state->in_eof = FT_BOOL( count < sizeof( state->in_buff ) );
if ( count > 0 )
result = 0;
}
return result;
}
/* return new code of 'num_bits', or -1 if eof
*/
static FT_Int32
ft_lzwstate_get_code( FT_LzwState state,
FT_UInt num_bits )
{
FT_Int32 result = -1;
FT_UInt32 pad = state->pad;
FT_UInt pad_bits = state->pad_bits;
while ( num_bits > pad_bits )
{
if ( state->in_cursor >= state->in_limit &&
ft_lzwstate_refill( state ) < 0 )
goto Exit;
pad |= (FT_UInt32)(*state->in_cursor++) << pad_bits;
pad_bits += 8;
}
result = (FT_Int32)( pad & LZW_MASK(num_bits) );
state->pad_bits = pad_bits - num_bits;
state->pad = pad >> num_bits;
Exit:
return result;
}
/* grow the character stack
*/
static int
ft_lzwstate_stack_grow( FT_LzwState state )
{
if ( state->stack_top >= state->stack_size )
{
FT_Memory memory = state->memory;
FT_Error error;
FT_UInt old_size = state->stack_size;
FT_UInt new_size = old_size;
new_size = new_size + (new_size >> 1) + 4;
if ( state->stack == state->stack_0 )
{
state->stack = NULL;
old_size = 0;
}
if ( FT_RENEW_ARRAY( state->stack, old_size, new_size ) )
return -1;
state->stack_size = new_size;
}
return 0;
}
/* grow the prefix/suffix arrays
*/
static int
ft_lzwstate_prefix_grow( FT_LzwState state )
{
FT_UInt old_size = state->prefix_size;
FT_UInt new_size = old_size;
FT_Memory memory = state->memory;
FT_Error error;
if ( new_size == 0 ) /* first allocation -> 9 bits */
new_size = 512;
else
new_size += (new_size >> 2); /* don't grow too fast */
/* note that the 'suffix' array is located in the same memory block
* pointed to by 'prefix'
*
* I know that sizeof(FT_Byte) == 1 by definition, but it's clearer
* to write it literally
*/
if ( FT_REALLOC( state->prefix,
old_size*(sizeof(FT_UShort)+sizeof(FT_Byte)),
new_size*(sizeof(FT_UShort)+sizeof(FT_Byte)) ) )
return -1;
/* now adjust 'suffix' and move the data accordingly */
state->suffix = (FT_Byte*)(state->prefix + new_size);
FT_MEM_MOVE( state->suffix,
state->prefix + old_size,
old_size * sizeof(FT_Byte) );
state->prefix_size = new_size;
return 0;
}
FT_LOCAL_DEF( void )
ft_lzwstate_reset( FT_LzwState state )
{
state->in_cursor = state->in_buff;
state->in_limit = state->in_buff;
state->in_eof = 0;
state->pad_bits = 0;
state->pad = 0;
state->stack_top = 0;
state->num_bits = LZW_INIT_BITS;
state->phase = FT_LZW_PHASE_START;
}
FT_LOCAL_DEF( void )
ft_lzwstate_init( FT_LzwState state,
FT_Stream source )
{
FT_ZERO( state );
state->source = source;
state->memory = source->memory;
state->prefix = NULL;
state->suffix = NULL;
state->prefix_size = 0;
state->stack = state->stack_0;
state->stack_size = sizeof(state->stack_0);
ft_lzwstate_reset( state );
}
FT_LOCAL_DEF( void )
ft_lzwstate_done( FT_LzwState state )
{
FT_Memory memory = state->memory;
ft_lzwstate_reset( state );
if ( state->stack != state->stack_0 )
FT_FREE( state->stack );
FT_FREE( state->prefix );
state->suffix = NULL;
FT_ZERO( state );
}
#define FTLZW_STACK_PUSH(c) \
FT_BEGIN_STMNT \
if ( state->stack_top >= state->stack_size && \
ft_lzwstate_stack_grow( state ) < 0 ) \
goto Eof; \
\
state->stack[ state->stack_top++ ] = (FT_Byte)(c); \
FT_END_STMNT
FT_LOCAL_DEF( FT_ULong )
ft_lzwstate_io( FT_LzwState state,
FT_Byte* buffer,
FT_ULong out_size )
{
FT_ULong result = 0;
FT_UInt num_bits = state->num_bits;
FT_UInt free_ent = state->free_ent;
FT_UInt old_char = state->old_char;
FT_UInt old_code = state->old_code;
FT_UInt in_code = state->in_code;
if ( out_size == 0 )
goto Exit;
switch ( state->phase )
{
case FT_LZW_PHASE_START:
{
FT_Byte max_bits;
FT_Int32 c;
/* skip magic bytes, and read max_bits + block_flag */
if ( FT_Stream_Seek( state->source, 2 ) != 0 ||
FT_Stream_TryRead( state->source, &max_bits, 1 ) != 1 )
goto Eof;
state->max_bits = max_bits & LZW_BIT_MASK;
state->block_mode = max_bits & LZW_BLOCK_MASK;
state->max_free = (FT_UInt)((1UL << state->max_bits) - 256);
if ( state->max_bits > LZW_MAX_BITS )
goto Eof;
num_bits = LZW_INIT_BITS;
free_ent = (state->block_mode ? LZW_FIRST : LZW_CLEAR) - 256;
in_code = 0;
state->free_bits = num_bits < state->max_bits
? (FT_UInt)((1UL << num_bits) - 256)
: state->max_free+1;
c = ft_lzwstate_get_code( state, num_bits );
if ( c < 0 )
goto Eof;
old_code = old_char = (FT_UInt)c;
if ( buffer )
buffer[result] = (FT_Byte)old_char;
if ( ++result >= out_size )
goto Exit;
state->phase = FT_LZW_PHASE_CODE;
}
/* fall-through */
case FT_LZW_PHASE_CODE:
{
FT_Int32 c;
FT_UInt code;
NextCode:
c = ft_lzwstate_get_code( state, num_bits );
if ( c < 0 ) goto Eof;
code = (FT_UInt)c;
if ( code == LZW_CLEAR && state->block_mode )
{
free_ent = (LZW_FIRST-1)-256; /* why not LZW_FIRST-256 ? */
num_bits = LZW_INIT_BITS;
state->free_bits = num_bits < state->max_bits
? (FT_UInt)((1UL << num_bits) - 256)
: state->max_free+1;
c = ft_lzwstate_get_code( state, num_bits );
if ( c < 0 ) goto Eof;
code = (FT_UInt)c;
}
in_code = code; /* save code for later */
if ( code >= 256U )
{
/* special case for KwKwKwK */
if ( code-256U >= free_ent )
{
FTLZW_STACK_PUSH( old_char );
code = old_code;
}
while ( code >= 256U )
{
FTLZW_STACK_PUSH( state->suffix[code-256] );
code = state->prefix[code-256];
}
}
old_char = code;
FTLZW_STACK_PUSH(old_char);
state->phase = FT_LZW_PHASE_STACK;
}
/* fall-through */
case FT_LZW_PHASE_STACK:
{
while ( state->stack_top > 0 )
{
--state->stack_top;
if ( buffer )
buffer[result] = state->stack[state->stack_top];
if ( ++result == out_size )
goto Exit;
}
/* now create new entry */
if ( free_ent < state->max_free )
{
if ( free_ent >= state->prefix_size &&
ft_lzwstate_prefix_grow( state ) < 0 )
goto Eof;
FT_ASSERT( free_ent < state->prefix_size );
state->prefix[free_ent] = (FT_UShort) old_code;
state->suffix[free_ent] = (FT_Byte) old_char;
if ( ++free_ent == state->free_bits )
{
num_bits++;
state->free_bits = num_bits < state->max_bits
? (FT_UInt)((1UL << num_bits)-256)
: state->max_free+1;
}
}
old_code = in_code;
state->phase = FT_LZW_PHASE_CODE;
goto NextCode;
}
default: /* state == EOF */
;
}
Exit:
state->num_bits = num_bits;
state->free_ent = free_ent;
state->old_code = old_code;
state->old_char = old_char;
state->in_code = in_code;
return result;
Eof:
state->phase = FT_LZW_PHASE_EOF;
goto Exit;
}

142
src/lzw/ftzopen.h Normal file
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@ -0,0 +1,142 @@
#ifndef __FT_ZOPEN_H__
#define __FT_ZOPEN_H__
#include <ft2build.h>
#include FT_FREETYPE_H
/* this is a complete re-implementation of the LZW file reader,
* since the old one was incredibly badly written, and used
* 400 Kb of heap memory before decompressing anything.
*/
#define FT_LZW_IN_BUFF_SIZE 64
#define FT_LZW_DEFAULT_STACK_SIZE 64
#define LZW_INIT_BITS 9
#define LZW_MAX_BITS 16
#define LZW_CLEAR 256
#define LZW_FIRST 257
#define LZW_BIT_MASK 0x1f
#define LZW_BLOCK_MASK 0x80
#define LZW_MASK(n) ((1U << (n)) - 1U)
typedef enum
{
FT_LZW_PHASE_START = 0,
FT_LZW_PHASE_CODE,
FT_LZW_PHASE_STACK,
FT_LZW_PHASE_EOF
} FT_LzwPhase;
/* state of LZW decompressor
*
* small technical note:
*
* we use a few tricks in this implementation that are explained here to
* ease debugging and maintenance.
*
* - first of all, the "prefix" and "suffix" arrays contain the
* suffix and prefix for codes over 256, this means that:
*
* prefix_of(code) == state->prefix[ code-256 ]
* suffix_of(code) == state->suffix[ code-256 ]
*
* each prefix is a 16-bit code, and each suffix an 8-bit byte
*
* both arrays are stored in a single memory block, pointed to by
* 'state->prefix', this means that the following equality is always
* true:
*
* state->suffix == (FT_Byte*)(state->prefix + state->prefix_size)
*
* of course, state->prefix_size is the number of prefix/suffix slots
* in the arrays, corresponding to codes 256..255+prefix_size
*
* - 'free_ent' is the index of the next free entry in the "prefix"
* and "suffix" arrays. This means that the corresponding "next free
* code" is really '256+free_ent'
*
* moreover, 'max_free' is the maximum value that 'free_ent' can reach.
*
* 'max_free' corresponds to "(1 << max_bits) - 256". Note that this value
* is always <= 0xFF00, which means that both 'free_ent' and 'max_free' can
* be stored in FT_UInt variable, even on 16-bit machines.
*
* if 'free_ent == max_free', you cannot add new codes to the prefix/suffix
* table.
*
* - 'num_bits' is the current number of code bits, starting at 9 and
* growing each time 'free_ent' reaches the value of 'free_bits'. the
* latter is computed as follows:
*
* if num_bits < max_bits:
* free_bits = (1 << num_bits)-256
* else:
* free_bits = max_free + 1
*
* since the value of 'max_free + 1' can never be reached by 'free_ent',
* 'num_bits' cannot grow larger than 'max_bits'
*/
typedef struct
{
FT_LzwPhase phase;
FT_Int in_eof;
FT_Byte* in_cursor; /* current buffer pos */
FT_Byte* in_limit; /* current buffer limit */
FT_UInt32 pad; /* a pad value where incoming bits were read */
FT_Int pad_bits; /* number of meaningful bits in pad value */
FT_UInt max_bits; /* max code bits, from file header */
FT_Int block_mode; /* block mode flag, from file header */
FT_UInt max_free; /* (1 << max_bits) - 256 */
FT_UInt num_bits; /* current code bit number */
FT_UInt free_ent; /* index of next free entry */
FT_UInt free_bits; /* if free_ent reaches this, increment num_bits */
FT_UInt old_code;
FT_UInt old_char;
FT_UInt in_code;
FT_UShort* prefix; /* always dynamically allocated / reallocated */
FT_Byte* suffix; /* suffix = (FT_Byte*)(prefix + prefix_size) */
FT_UInt prefix_size; /* number of slots in 'prefix' or 'suffix' */
FT_Byte* stack; /* character stack */
FT_UInt stack_top;
FT_UInt stack_size;
FT_Byte in_buff[ FT_LZW_IN_BUFF_SIZE ]; /* small buffer to read data */
FT_Byte stack_0[ FT_LZW_DEFAULT_STACK_SIZE ]; /* minimize heap alloc */
FT_Stream source; /* source stream */
FT_Memory memory;
} FT_LzwStateRec, *FT_LzwState;
FT_LOCAL( void )
ft_lzwstate_init( FT_LzwState state,
FT_Stream source );
FT_LOCAL( void )
ft_lzwstate_done( FT_LzwState state );
FT_LOCAL( void )
ft_lzwstate_reset( FT_LzwState state );
FT_LOCAL( FT_ULong )
ft_lzwstate_io( FT_LzwState state,
FT_Byte* buffer,
FT_ULong out_size );
/* */
#endif /* __FT_ZOPEN_H__ */

View File

@ -28,12 +28,12 @@ LZW_COMPILE := $(FT_COMPILE) $I$(subst /,$(COMPILER_SEP),$(LZW_DIR))
# LZW support sources (i.e., C files)
#
LZW_DRV_SRC := $(LZW_DIR)/ftlzw.c \
$(LZW_DIR)/zopen.c
LZW_DRV_SRC := $(LZW_DIR)/ftlzw2.c
# LZW support headers
#
LZW_DRV_H := $(LZW_DIR)/zopen.h
LZW_DRV_H := $(LZW_DIR)/ftzopen.h \
$(LZW_DIR)/ftzopen.c
# LZW driver object(s)
@ -41,12 +41,12 @@ LZW_DRV_H := $(LZW_DIR)/zopen.h
# LZW_DRV_OBJ_M is used during `multi' builds
# LZW_DRV_OBJ_S is used during `single' builds
#
LZW_DRV_OBJ_M := $(OBJ_DIR)/ftlzw.$O
LZW_DRV_OBJ_S := $(OBJ_DIR)/ftlzw.$O
LZW_DRV_OBJ_M := $(OBJ_DIR)/ftlzw2.$O
LZW_DRV_OBJ_S := $(OBJ_DIR)/ftlzw2.$O
# LZW support source file for single build
#
LZW_DRV_SRC_S := $(LZW_DIR)/ftlzw.c
LZW_DRV_SRC_S := $(LZW_DIR)/ftlzw2.c
# LZW support - single object