gstreamer/libs/getbits/gstgetbits_generic.c

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#include <glib.h>
#include "gstgetbits.h"
unsigned long _gst_getbits_int_cb(gst_getbits_t *gb, unsigned long bits);
unsigned long _gst_get1bit_int(gst_getbits_t *gb, unsigned long bits);
unsigned long _gst_getbits_int(gst_getbits_t *gb, unsigned long bits);
unsigned long _gst_getbits_fast_int(gst_getbits_t *gb, unsigned long bits);
unsigned long _gst_showbits_int(gst_getbits_t *gb, unsigned long bits);
void _gst_flushbits_int(gst_getbits_t *gb, unsigned long bits);
void _gst_getbits_back_int(gst_getbits_t *gb, unsigned long bits);
unsigned long _gst_getbits_int_cb(gst_getbits_t *gb, unsigned long bits) {
int result;
int bitsleft;
//printf("gst_getbits%lu %ld %p %08x\n", bits, gb->bits, gb->ptr, gb->dword);
if (!bits) return 0;
gb->bits -= bits;
result = gb->dword >> (32-bits);
if (gb->bits < 0) {
gb->ptr += 4;
bitsleft = (gb->endptr - gb->ptr)*8;
bits = -gb->bits;
gb->bits += (bitsleft>32? 32 : bitsleft);
if (gb->endptr <= gb->ptr) {
(gb->callback)(gb, gb->data);
gb->bits -= bits;
}
gb->dword = swab32(*((unsigned long *)(gb->ptr)));
result |= (gb->dword >> (32-bits));
}
gb->dword <<= bits;
return result;
}
unsigned long _gst_get1bit_int(gst_getbits_t *gb, unsigned long bits) {
unsigned char rval;
rval = *gb->ptr << gb->bits;
gb->bits++;
gb->ptr += (gb->bits>>3);
gb->bits &= 0x7;
DEBUG("getbits%d, %08x\n", bits, rval);
return rval>>7;
}
unsigned long _gst_getbits_int(gst_getbits_t *gb, unsigned long bits) {
unsigned long rval;
if (bits == 0) return 0;
rval = swab32(*((unsigned long *)(gb->ptr)));
rval <<= gb->bits;
gb->bits += bits;
rval >>= (32-bits);
gb->ptr += (gb->bits>>3);
gb->bits &= 0x7;
DEBUG("getbits%d, %08x\n", bits, rval);
return rval;
}
unsigned long _gst_getbits_fast_int(gst_getbits_t *gb, unsigned long bits) {
unsigned long rval;
rval = (unsigned char) (gb->ptr[0] << gb->bits);
rval |= ((unsigned int) gb->ptr[1] << gb->bits)>>8;
rval <<= bits;
rval >>= 8;
gb->bits += bits;
gb->ptr += (gb->bits>>3);
gb->bits &= 0x7;
DEBUG("getbits%d, %08x\n", bits, rval);
return rval;
}
unsigned long _gst_showbits_int(gst_getbits_t *gb, unsigned long bits) {
unsigned long rval;
if (bits == 0) return 0;
rval = swab32(*((unsigned long *)(gb->ptr)));
rval <<= gb->bits;
rval >>= (32-bits);
DEBUG("showbits%d, %08x\n", bits, rval);
return rval;
}
void _gst_flushbits_int(gst_getbits_t *gb, unsigned long bits) {
gb->bits += bits;
gb->ptr += (gb->bits>>3);
gb->bits &= 0x7;
DEBUG("flushbits%d\n", bits);
}
void _gst_getbits_back_int(gst_getbits_t *gb, unsigned long bits) {
gb->bits -= bits;
gb->ptr += (gb->bits>>3);
gb->bits &= 0x7;
}