45 lines
1.0 KiB
C
45 lines
1.0 KiB
C
#include "./bitstream.h"
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#include <stdio.h>
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BitStream bitstream_load_from_file(FILE *fp) {
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fseek(fp, SEEK_END, 0);
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size_t length = ftell(fp);
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fseek(fp, SEEK_SET, 0);
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BitStream bs = bitstream_init_empty(length);
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fread(bs.buffer, 1, length, fp);
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return bs;
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}
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BitStream bitstream_init_empty(size_t size_in_bytes) {
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return (BitStream){
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.buffer = malloc(size_in_bytes),
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.buffer_size = size_in_bytes,
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.offset = 0
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};
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}
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bool bitstream_end(BitStream bs) {
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return (bs.offset >> 3) >= bs.buffer_size;
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}
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uint8_t bitstream_get(BitStream bs, off_t offset) {
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return bs.buffer[offset >> 3] & (0x80 >> (offset & 7)) ? 1 : 0;
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}
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uint8_t bitstream_next(BitStream *bs) {
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uint8_t val = bitstream_get(*bs, bs->offset);
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bs->offset++;
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return val;
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}
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void bitstream_set(BitStream bs, off_t offset, uint8_t value) {
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bs.buffer[offset >> 3] &= ~(0x80 >> (offset & 7));
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bs.buffer[offset >> 3] |= (value ? 1 : 0) * (0x80 >> (offset & 7));
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}
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void bitstream_unload(BitStream *bs) {
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free(bs->buffer);
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bs->buffer = 0;
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}
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