mirror of https://bitbucket.org/ausocean/av.git
73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
/*
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DESCRIPTION
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helpers.c provides C helper functions for interfacing with C code used for
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testing in this package.
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AUTHORS
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Saxon A. Nelson-Milton <saxon@ausocean.org>
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LICENSE
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Copyright (C) 2019 the Australian Ocean Lab (AusOcean).
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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in gpl.txt. If not, see http://www.gnu.org/licenses.
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*/
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#include "helpers.h"
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typedef struct BitReader BitReader;
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typedef struct Reader Reader;
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BitReader* new_BitReader(char* d, int l){
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Reader* r = (Reader*)malloc(sizeof(Reader));
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r->data = d;
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r->curr = 0;
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r->len = l;
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r->err = 0;
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BitReader* br = (BitReader*)malloc(sizeof(BitReader));
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br->r = r;
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br->n = 0;
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br->bits = 0;
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br->nRead = 0;
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br->err = 0;
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return br;
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}
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char next_byte(Reader *r) {
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if(r->curr >= r->len){
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r->err = 1;
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}
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char next = r->data[r->curr];
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r->curr++;
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return next;
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}
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uint64_t read_bits(BitReader *br, int n) {
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while( n > br->bits ){
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char b = next_byte(br->r);
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if(br->r->err != 0){
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br->err = 1;
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return 0;
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}
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br->nRead++;
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br->n <<= 8;
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br->n |= (uint64_t)b;
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br->bits += 8;
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}
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uint64_t r = (br->n >> (br->bits-n)) & ((1 << n) - 1);
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br->bits -= n;
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return r;
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}
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