gstreamer/libs/gst/getbits/gstgetbits_generic.c

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#include "getbits.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;
GST_DEBUG ("getbits%ld, %08x", 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;
GST_DEBUG ("getbits%ld, %08lx", 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;
GST_DEBUG ("getbits%ld, %08lx", 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);
GST_DEBUG ("showbits%ld, %08lx", 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;
GST_DEBUG ("flushbits%ld", bits);
}
void
_gst_getbits_back_int (gst_getbits_t * gb, unsigned long bits)
{
gb->bits -= bits;
gb->ptr += (gb->bits >> 3);
gb->bits &= 0x7;
}