int main(int argc, char *argv[])
{
int len;
v42bis_state_t state_a;
v42bis_state_t state_b;
uint8_t buf[1024];
int in_fd;
int v42bis_fd;
int out_fd;
int do_compression;
int do_decompression;
time_t now;
do_compression = TRUE;
do_decompression = TRUE;
if (argc < 2)
{
fprintf(stderr, "Usage: %s <file>\n", argv[0]);
exit(2);
}
if (do_compression)
{
if ((in_fd = open(argv[1], O_RDONLY)) < 0)
{
fprintf(stderr, "Error opening file '%s'.\n", argv[1]);
exit(2);
}
if ((v42bis_fd = open(COMPRESSED_FILE_NAME, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0)
{
fprintf(stderr, "Error opening file '%s'.\n", COMPRESSED_FILE_NAME);
exit(2);
}
time(&now);
v42bis_init(&state_a, 3, 512, 6, frame_handler, (void *) (intptr_t) v42bis_fd, 512, data_handler, NULL, 512);
v42bis_compression_control(&state_a, V42BIS_COMPRESSION_MODE_ALWAYS);
in_octets_to_date = 0;
out_octets_to_date = 0;
while ((len = read(in_fd, buf, 1024)) > 0)
{
if (v42bis_compress(&state_a, buf, len))
{
fprintf(stderr, "Bad return code from compression\n");
exit(2);
}
in_octets_to_date += len;
}
v42bis_compress_flush(&state_a);
printf("%d bytes compressed to %d bytes in %lds\n", in_octets_to_date, out_octets_to_date, time(NULL) - now);
close(in_fd);
close(v42bis_fd);
}
if (do_decompression)
{
/* Now open the files for the decompression. */
if ((v42bis_fd = open(COMPRESSED_FILE_NAME, O_RDONLY)) < 0)
{
fprintf(stderr, "Error opening file '%s'.\n", COMPRESSED_FILE_NAME);
exit(2);
}
if ((out_fd = open(OUTPUT_FILE_NAME, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0)
{
fprintf(stderr, "Error opening file '%s'.\n", OUTPUT_FILE_NAME);
exit(2);
}
time(&now);
v42bis_init(&state_b, 3, 512, 6, frame_handler, (void *) (intptr_t) v42bis_fd, 512, data_handler, (void *) (intptr_t) out_fd, 512);
in_octets_to_date = 0;
out_octets_to_date = 0;
while ((len = read(v42bis_fd, buf, 1024)) > 0)
{
if (v42bis_decompress(&state_b, buf, len))
{
fprintf(stderr, "Bad return code from decompression\n");
exit(2);
}
in_octets_to_date += len;
}
v42bis_decompress_flush(&state_b);
printf("%d bytes decompressed to %d bytes in %lds\n", in_octets_to_date, out_octets_to_date, time(NULL) - now);
close(v42bis_fd);
close(out_fd);
}
return 0;
}
/* Compress a packet using V.42bis data compression */
static int v42bis_compress_unitdata(uint8_t *pcomp_index, uint8_t *data,
unsigned int len, v42bis_state_t *comp)
{
/* Note: This implementation may only be used to compress SN_UNITDATA
* packets, since it resets the compression state for each NPDU. */
uint8_t *data_o;
int rc;
int skip = 0;
struct v42bis_output_buffer compressed_data;
/* Don't bother with short packets */
if (len < MIN_COMPR_PAYLOAD)
skip = 1;
/* Skip if compression is not enabled for TX direction */
if (!comp->compress.v42bis_parm_p0)
skip = 1;
/* Skip compression */
if (skip) {
*pcomp_index = 0;
return len;
}
/* Reset V.42bis compression state */
v42bis_reset(comp);
/* Run compressor */
data_o = talloc_zero_size(comp, len * MAX_DATADECOMPR_FAC);
compressed_data.buf = data_o;
compressed_data.buf_pointer = data_o;
compressed_data.len = 0;
comp->compress.user_data = (&compressed_data);
rc = v42bis_compress(comp, data, len);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"Data compression failed, skipping...\n");
skip = 1;
}
rc = v42bis_compress_flush(comp);
if (rc < 0) {
LOGP(DSNDCP, LOGL_ERROR,
"Data compression failed, skipping...\n");
skip = 1;
}
/* The compressor might yield negative compression gain, in
* this case, we just decide to send the packat as normal,
* uncompressed payload => skip compresssion */
if (compressed_data.len >= len) {
LOGP(DSNDCP, LOGL_ERROR,
"Data compression ineffective, skipping...\n");
skip = 1;
}
/* Skip compression */
if (skip) {
*pcomp_index = 0;
talloc_free(data_o);
return len;
}
*pcomp_index = 1;
memcpy(data, data_o, compressed_data.len);
talloc_free(data_o);
return compressed_data.len;
}
