/*
* The main loop for expansion is very similar to the expansion
* routine used in the simpler compression program, ARITH1E.C. The
* routine first has to initialize the the arithmetic coder and the
* model. The decompression loop differs in a couple of respect.
* First of all, it handles the special ESCAPE character, by
* removing them from the input bit stream but just throwing them
* away otherwise. Secondly, it handles the special FLUSH character.
* Once the main decoding loop is done, the cleanup code is called,
* and the program exits.
*
*/
void ExpandFile(BIT_FILE *input,FILE *output,int argc,char *argv[])
{
SYMBOL s;
int c;
int count;
initialize_options( argc, argv );
initialize_model();
initialize_arithmetic_decoder( input );
for ( ; ; ) {
do {
get_symbol_scale( &s );
count = get_current_count( &s );
c = convert_symbol_to_int( count, &s );
remove_symbol_from_stream( input, &s );
} while ( c == ESCAPE );
if ( c == DONE )
break;
if ( c != FLUSH )
putc( (char) c, output );
else
flush_model();
update_model( c );
add_character_to_model( c );
}
}
static int decode_arith_symbol(MscCoderArithModel *arithModel, GetBitContext *gb) {
MscCoderArithSymbol arithSymbol;
int count, value;
// get range symbol
get_symbol_scale(arithModel, &arithSymbol);
// get value for symbol
count = get_current_count(&arithSymbol);
value = convert_symbol_to_int(arithModel, count, &arithSymbol);
// remove symbol from stream
remove_symbol_from_stream(gb, &arithSymbol);
// update arithmetic coder model
update_model(arithModel, value);
return value;
}
