static int crc_write_header(struct AVFormatContext *s)
{
CRCState *crc = s->priv_data;
/* init CRC */
crc->crcval = update_adler32(0, NULL, 0);
return 0;
}
static int crc_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
CRCState *crc = s->priv_data;
crc->crcval = update_adler32(crc->crcval, pkt->data, pkt->size);
return 0;
}
int unpack(void *input, size_t input_size, void** output)
{
int chunk_id;
int chunk_options;
int pos = 0;
unsigned long chunk_size;
unsigned long chunk_checksum;
unsigned long chunk_extra;
unsigned char buffer[BLOCK_SIZE];
unsigned long checksum;
unsigned long decompressed_size;
unsigned long total_extracted;
unsigned char* compressed_buffer;
unsigned char* decompressed_buffer;
unsigned long compressed_bufsize;
unsigned long decompressed_bufsize;
unsigned char* b_input = (unsigned char*) input;
size_t output_size = 0;
/* sanity check */
if (input_size < 8) {
php_error_docref(NULL TSRMLS_CC, E_NOTICE, "Data too short");
return -1;
}
input_size = input_size + sizeof(sixpack_magic);
/* not a 6pack archive? */
if(!detect_magic(input, input_size))
{
php_error_docref(NULL TSRMLS_CC, E_NOTICE, "Data not in 6pack format");
return -1;
}
/* position of first chunk */
pos = 8;
/* initialize */
total_extracted = 0;
decompressed_size = 0;
compressed_buffer = 0;
decompressed_buffer = 0;
compressed_bufsize = 0;
decompressed_bufsize = 0;
/* main loop */
for(;;)
{
/* end of file? */
if(pos > input_size)
break;
read_chunk_header(input, input_size, &pos, &chunk_id, &chunk_options,
&chunk_size, &chunk_checksum, &chunk_extra);
if((chunk_id == 1) && (chunk_size > 10) && (chunk_size < BLOCK_SIZE))
{
/* file entry */
int c;
for (c=0;c<chunk_size;c++)
{
if (pos < input_size) {
buffer[c] = b_input[pos];
pos++;
} else {
break;
}
}
checksum = update_adler32(1L, buffer, chunk_size);
if(checksum != chunk_checksum)
{
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Checksum mismatch. Got %08lX, expected %08lX", checksum, chunk_checksum);
return (-1);
}
decompressed_size = readU32(buffer);
total_extracted = 0;
}
if((chunk_id == 17) && decompressed_size)
{
unsigned long remaining;
/* uncompressed */
switch(chunk_options)
{
/* stored, simply copy to output */
case 0:
/* read one block at at time, write and update checksum */
total_extracted += chunk_size;
remaining = chunk_size;
checksum = 1L;
for(;;)
{
unsigned long r = (BLOCK_SIZE < remaining) ? BLOCK_SIZE: remaining;
int c;
for (c=0;c<r;c++)
{
if (pos<input_size) {
buffer[c] = b_input[pos];
pos++;
} else{
break;
}
}
size_t bytes_read = c;
if(bytes_read == 0)
break;
output_size = mem_append(output, output_size, buffer, bytes_read);
checksum = update_adler32(checksum, buffer, bytes_read);
remaining -= bytes_read;
}
/* verify everything is written correctly */
if(checksum != chunk_checksum)
{
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Checksum mismatch. Got %08lX, expected %08lX", checksum, chunk_checksum);
return (-1);
}
break;
/* compressed using FastLZ */
case 1:
/* enlarge input buffer if necessary */
if(chunk_size > compressed_bufsize)
{
compressed_bufsize = chunk_size;
efree(compressed_buffer);
compressed_buffer = (unsigned char*)emalloc(compressed_bufsize);
}
/* enlarge output buffer if necessary */
if(chunk_extra > decompressed_bufsize)
{
decompressed_bufsize = chunk_extra;
efree(decompressed_buffer);
decompressed_buffer = (unsigned char*)emalloc(decompressed_bufsize);
}
/* read and check checksum */
int c;
for (c=0;c<chunk_size;c++)
{
if (pos<input_size) {
compressed_buffer[c] = b_input[pos];
pos++;
} else{
break;
}
}
checksum = update_adler32(1L, compressed_buffer, chunk_size);
total_extracted += chunk_extra;
/* verify that the chunk data is correct */
if(checksum != chunk_checksum)
{
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Checksum mismatch. Got %08lX, expected %08lX", checksum, chunk_checksum);
return (-1);
}
else
{
/* decompress and verify */
remaining = fastlz_decompress(compressed_buffer, chunk_size, decompressed_buffer, chunk_extra);
if(remaining != chunk_extra)
{
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Decompression failed. Skipped");
}
else
output_size = mem_append(output, output_size, decompressed_buffer, chunk_extra);
}
break;
default:
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Unknown compression method (%d)\n", chunk_options);
break;
}
}
/* position of next chunk */
//pos = pos + 16 + chunk_size;
//fseek(in, pos + 16 + chunk_size, SEEK_SET);
}
/* free allocated stuff */
efree(compressed_buffer);
efree(decompressed_buffer);
/* so far so good */
return total_extracted;
}
unsigned long adler32(unsigned char *buf, int len)
{
return update_adler32(1L, buf, len);
}
