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