windows-nt/Source/XPSP1/NT/enduser/stuff/itss/lzx/encoder/encapi.c
2020-09-26 16:20:57 +08:00

166 lines
3.5 KiB
C

/*
* encapi.c
*
* Encoder API entrypoints.
*/
#define ALLOC_VARS
#include "encoder.h"
bool LZX_EncodeInit(
t_encoder_context *context,
long compression_window_size,
long second_partition_size,
PFNALLOC pfnma,
PFNFREE pfnmf,
int FAR (DIAMONDAPI *pfnlzx_output_callback)(
void * pfol,
unsigned char * compressed_data,
long compressed_size,
long uncompressed_size
),
void *fci_data
)
{
#ifdef _DEBUG
_CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
_CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDOUT);
_CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE);
_CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDOUT);
_CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE);
_CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDOUT);
#endif
/* to pass back in lzx_output_callback() */
context->enc_fci_data = fci_data;
context->enc_window_size = compression_window_size;
/*
* The second partition size must be a multiple of 32K
*/
if (second_partition_size & (CHUNK_SIZE-1))
second_partition_size &= (~(CHUNK_SIZE-1));
/*
* The minimum allowed is 32K because of the way that
* our translation works.
*/
if (second_partition_size < CHUNK_SIZE)
second_partition_size = CHUNK_SIZE;
/*
* Our window size must be at least 32K
*/
if (compression_window_size < CHUNK_SIZE)
return false;
context->enc_encoder_second_partition_size = second_partition_size;
context->enc_output_callback_function = pfnlzx_output_callback;
context->enc_malloc = pfnma;
context->enc_free = pfnmf;
/* Error allocating memory? */
if (comp_alloc_compress_memory(context) == false)
return false;
LZX_EncodeNewGroup(context);
return true;
}
/*
* Cleanup (frees memory)
*/
void LZX_EncodeFree(t_encoder_context *context)
{
comp_free_compress_memory(context);
}
/*
* Sets up the encoder for a new group of files.
*
* All this does is reset the lookup table, re-initialise to the
* default match estimation tables for the optimal parser, and
* reset a few variables.
*/
void LZX_EncodeNewGroup(t_encoder_context *context)
{
init_compression_memory(context);
}
long LZX_Encode(
t_encoder_context *context,
byte *input_data,
long input_size,
long *estimated_bytes_compressed,
long file_size_for_translation
)
{
context->enc_input_ptr = input_data;
context->enc_input_left = input_size;
context->enc_file_size_for_translation = file_size_for_translation;
/* perform the encoding */
encoder_start(context);
if (context->enc_output_overflow)
{
*estimated_bytes_compressed = 0;
return ENCODER_WRITE_FAILURE;
}
*estimated_bytes_compressed = estimate_buffer_contents(context);
return ENCODER_SUCCESS;
}
bool LZX_EncodeFlush(t_encoder_context *context)
{
flush_all_pending_blocks(context);
if (context->enc_output_overflow)
return false;
return true;
}
unsigned char *LZX_GetInputData(
t_encoder_context *context,
unsigned long *input_position,
unsigned long *bytes_available
)
{
unsigned long filepos;
// note that BufPos-window_size is the real position in the file
filepos = context->enc_BufPos - context->enc_window_size;
if (filepos < context->enc_window_size)
{
*input_position = 0;
*bytes_available = filepos;
return &context->enc_MemWindow[context->enc_window_size];
}
else
{
*input_position = filepos - context->enc_window_size;
*bytes_available = context->enc_window_size;
return &context->enc_MemWindow[context->enc_BufPos - context->enc_window_size];
}
}