Source code of Windows XP (NT5)
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161 lines
3.5 KiB

/*
* decapi.c
*
* API entry points.
*/
#define ALLOC_VARS
#include "decoder.h"
#include <stdio.h>
#include <memory.h>
#pragma intrinsic(memcpy)
bool __stdcall LZX_DecodeInit(
t_decoder_context **dec_context,
long compression_window_size,
PFNALLOC pfnma,
HANDLE hAllocator
)
{
t_decoder_context *context= pfnma( hAllocator, sizeof( t_decoder_context ));
if ( context == NULL ) {
return false;
}
*dec_context = context;
context->dec_malloc = pfnma;
context->dec_mallochandle = hAllocator;
context->dec_window_size = compression_window_size;
context->dec_window_mask = context->dec_window_size - 1;
/*
* Window size must be a power of 2
*/
if (context->dec_window_size & context->dec_window_mask)
return false;
if (allocate_decompression_memory(context) == false)
return false;
LZX_DecodeNewGroup(context);
return true;
}
void __fastcall LZX_DecodeNewGroup(t_decoder_context *context)
{
reset_decoder_trees(context);
decoder_misc_init(context);
init_decoder_translation(context);
context->dec_num_cfdata_frames = 0;
}
int __stdcall LZX_Decode(
t_decoder_context *context,
long bytes_to_decode,
byte * compressed_input_buffer,
long compressed_input_size,
byte * uncompressed_output_buffer,
long uncompressed_output_size,
long * bytes_decoded
)
{
long result;
context->dec_input_curpos = compressed_input_buffer;
context->dec_end_input_pos = (compressed_input_buffer + compressed_input_size + 4);
context->dec_output_buffer = uncompressed_output_buffer;
init_decoder_input(context);
result = decode_data(context, bytes_to_decode);
context->dec_num_cfdata_frames++;
if (result < 0)
{
*bytes_decoded = 0;
return 1; /* failure */
}
else
{
*bytes_decoded = result;
context->dec_position_at_start += result;
return 0; /* success */
}
}
//
// Warning, this dictionary is inserted verbatim, and is not E8
// translated. If the encoder did E8 translation on its preloaded
// dictionary, this won't work.
//
#ifdef TRACING
ulong TracingOldDataSize;
#endif
#define ROUNDUP2( x, n ) ((((ULONG)(x)) + (((ULONG)(n)) - 1 )) & ~(((ULONG)(n)) - 1 ))
bool __fastcall LZX_DecodeInsertDictionary(
t_decoder_context * context,
const byte * data,
unsigned long data_size
)
{
if (data_size > context->dec_window_size)
return false;
#ifdef TRACING
TracingOldDataSize = context->dec_window_size + ROUNDUP2( data_size, CHUNK_SIZE );
#endif
memcpy(
&context->dec_mem_window[context->dec_window_size - data_size],
data,
data_size
);
return true;
}
#ifdef TRACING
void
__stdcall
TracingMatch(
ulong BufPos,
ulong MatchPos,
ulong WindowSize,
ulong MatchLength,
ulong MatchPosSlot
)
{
printf( "MATCH: At %08X, From %08X, Length %5d\n", BufPos + TracingOldDataSize, MatchPos + TracingOldDataSize, MatchLength );
}
void
__stdcall
TracingLiteral(
ulong BufPos,
ulong ch
)
{
printf( "LITER: At %08X, 0x%02X\n", BufPos + TracingOldDataSize, ch );
}
#endif /* TRACING */