hexcode.c

/*
 * CDDL HEADER START
 *
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 *
 * CDDL HEADER END
*/
/*
 * Copyright 2023 Saso Kiselkov. All rights reserved.
 */
 
#include <ctype.h>
#include <stdint.h>
#include <stdio.h>
 
#include "acfutils/assert.h"
#include "acfutils/hexcode.h"
 
API_EXPORT void
hex_enc(const void *in_raw, size_t len, void *out_enc, size_t out_cap)
{
    const uint8_t *in_8b = in_raw;
    char *out = out_enc;
 
    ASSERT(in_raw != NULL || len == 0);
    ASSERT(out_enc != NULL || out_cap == 0);
 
    /* guarantee zero-termination of output */
    if (out_cap != 0)
        *out = 0;
    for (size_t i = 0, j = 0; i < len && j + 3 <= out_cap; i++, j += 2)
        sprintf(&out[j], "%02x", (unsigned)in_8b[i]);
}
 
static inline int
xdigit2int(char c)
{
    if (c >= '0' && c <= '9')
        return (c - '0');
    if (c >= 'A' && c <= 'F')
        return (c - 'A' + 10);
    if (c >= 'a' && c <= 'f')
        return (c - 'a' + 10);
    return (-1);
}
 
API_EXPORT bool_t
hex_dec(const void *in_enc, size_t len, void *out_raw, size_t out_cap)
{
    const char *in_str = in_enc;
    uint8_t *out = out_raw;
 
    /* Input length must be a multiple of two and fit into output */
    if ((len % 2 != 0) || (out_cap < len / 2))
        return (B_FALSE);
 
    for (size_t i = 0, j = 0; i < len && j < out_cap; i += 2, j++) {
        int a = xdigit2int(in_str[i]);
        int b = xdigit2int(in_str[i + 1]);
 
        if (a == -1 || b == -1)
            return (B_FALSE);
        out[j] = (a << 4) | b;
    }
 
    return (B_TRUE);
}