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#include <leb128.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
/* The functions below are (somewhat heavily) modified versions of those
* provided by the wac project: https://github.com/kanaka/wac */
/*
* Copyright (C) Joel Martin <github@martintribe.org>
* The wac project is licensed under the MPL 2.0 (Mozilla Public License
* 2.0). The text of the MPL 2.0 license is included below and can be
* found at https://www.mozilla.org/MPL/2.0/
*/
static int read_LEB(FILE *const f, const unsigned maxbits,
const bool sign, unsigned long long *const out)
{
unsigned long long result = 0;
unsigned shift = 0, bcnt = 0;
uint8_t byte;
for (;;)
{
if (!fread(&byte, sizeof byte, 1, f))
return -1;
result |= (unsigned long long)(byte & 0x7f) << shift;
shift += 7;
if (!(byte & 0x80))
break;
else if (++bcnt > (maxbits + 7 - 1) / 7)
{
fprintf(stderr, "%s: overflow\n", __func__);
return -1;
}
}
if (sign && (shift < maxbits) && (byte & 0x40))
result |= -1ll << shift;
*out = result;
return 0;
}
int leb128_read_unsigned(FILE *const f, const unsigned maxbits,
unsigned long long *const out)
{
return read_LEB(f, maxbits, false, out);
}
int leb128_read_signed(FILE *const f, const unsigned maxbits,
long long *const out)
{
unsigned long long value;
const int ret = read_LEB(f, maxbits, true, &value);
*out = value;
return ret;
}
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