/*
* This expansion routine demonstrates the basic algorithm used for
* decompression in this article. It first goes to the modeling
* module and gets the scale for the current context. (Note that
* the scale is fixed here, since this is not an adaptive model).
* It then asks the arithmetic decoder to give a high and low
* value for the current input number scaled to match the current
* range. Finally, it asks the modeling unit to convert the
* high and low values to a symbol.
*/
void expand()
{
FILE *compressed_file;
SYMBOL s;
char c;
int count;
compressed_file=fopen( "software/benchmarks/data/test_comp.cmp", "rb" );
if ( compressed_file == NULL )
error_exit( "Could not open output file" );
puts( "Decoding..." );
printf( "Incoming characters: " );
initialize_input_bitstream();
initialize_arithmetic_decoder( compressed_file );
for ( ; ; )
{
s.scale = 11;
count = get_current_count( &s );
c = convert_symbol_to_int( count, &s );
if ( c == '\0' )
break;
remove_symbol_from_stream( compressed_file, &s );
putc( c, stdout );
}
putc( '\n', stdout );
}
/**
* Decompresses the data in an input file and writes it in a new file.
* @param[in] filename name and path of the input file.
* @param[in] output name and path of the output file.
* @param[in] see if see will be used.
*/
static void unzip(char *filename, char *output, BOOL see) {
FILE *output_file, *compressed_file;
int i, header, parts, part;
Uint textlen = 0;
decoderTree_t tree;
initDecoderTreeStack();
compressed_file = fopen(filename, "rb");
if (!compressed_file) {
perror( "Could not open input file");
exit(1);
}
if (!output) {
output = strrchr(filename, '.');
if (output) {
*output = '\0';
}
else {
strcat(filename, ".out");
}
output = filename;
}
output_file = fopen(output, "wb");
if (!output_file) {
perror( "Could not open output file");
exit(1);
}
/* check magic */
header = getc(compressed_file) << 8;
header += getc(compressed_file);
if (header != MAGIC) {
fprintf(stderr, "Invalid compressed file\n");
exit(1);
}
/* read parts */
parts = getc(compressed_file);
initialize_input_bitstream();
initialize_arithmetic_decoder(compressed_file);
readAlphabet(compressed_file);
setMaxCount();
for (part = 1; part <= parts; part++) {
printf("---------- part %d ---------------\n", part);
/* read textlen */
for (textlen=0, i=3; i>=0; i--) {
textlen += readByte(compressed_file) << (8 * i);
}
/*if (part == 1) {*/
tree = readDecoderTree(compressed_file);
/*}*/
printf("Tree built\n");
printf("Textlen: %ld\n", textlen);
printf("FSM...\n");
/*if (part == 1) {*/
DEBUGCODE(printDecoderTree(tree));
makeDecoderFsm(tree);
DEBUGCODE(printDecoderTree(tree));
/*}*/
printf("Decoding...\n");
decode(tree, textlen, compressed_file, output_file, see);
}
/*freeDecoderTree(tree);*/
fclose(compressed_file);
fclose(output_file);
}
