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// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later
#include <stdint.h>
#include <stdlib.h>
#include "hexlify.h"
void hexlify(const void *in, size_t in_len, char *out)
{
static const char nibble_to_hex_digit[] = "0123456789abcdef";
for (size_t i = 0; i < in_len; i++) {
uint8_t byte = ((uint8_t *)in)[i];
out[2 * i] = nibble_to_hex_digit[byte >> 4];
out[2 * i + 1] = nibble_to_hex_digit[byte & 0xf];
}
}
char *ahexlify(const void *in, size_t in_len)
{
size_t out_size;
if (__builtin_mul_overflow(in_len, 2U, &out_size) ||
__builtin_add_overflow(out_size, 1U, &out_size))
return NULL;
char *out = malloc(out_size);
if (!out)
return NULL;
hexlify(in, in_len, out);
out[out_size - 1] = '\0';
return out;
}
static inline bool hex_digit_to_nibble(char c, uint8_t *ret)
{
if ('0' <= c && c <= '9')
*ret = c - '0';
else if ('a' <= c && c <= 'f')
*ret = c - 'a' + 10;
else if ('A' <= c && c <= 'F')
*ret = c - 'A' + 10;
else
return false;
return true;
}
bool unhexlify(const char *in, size_t in_len, void *out)
{
if (in_len % 2)
return false;
for (size_t i = 0; i < in_len; i += 2) {
uint8_t lo, hi;
if (!hex_digit_to_nibble(in[i], &hi) ||
!hex_digit_to_nibble(in[i + 1], &lo))
return false;
((uint8_t *)out)[i / 2] = (hi << 4) | lo;
}
return true;
}
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