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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: hex.c,v 1.5 2020/02/26 18:47:59 florian Exp $ */
/*! \file */
#include <ctype.h>
#include <string.h>
#include <isc/buffer.h>
#include <isc/hex.h>
#include <isc/region.h>
#include <isc/types.h>
#include <isc/util.h>
#define RETERR(x) do { \
isc_result_t _r = (x); \
if (_r != ISC_R_SUCCESS) \
return (_r); \
} while (0)
static const char hex[] = "0123456789ABCDEF";
isc_result_t
isc_hex_totext(isc_region_t *source, int wordlength,
const char *wordbreak, isc_buffer_t *target)
{
char buf[3];
unsigned int loops = 0;
if (wordlength < 2)
wordlength = 2;
memset(buf, 0, sizeof(buf));
while (source->length > 0) {
buf[0] = hex[(source->base[0] >> 4) & 0xf];
buf[1] = hex[(source->base[0]) & 0xf];
RETERR(isc_str_tobuffer(buf, target));
isc_region_consume(source, 1);
loops++;
if (source->length != 0 &&
(int)((loops + 1) * 2) >= wordlength)
{
loops = 0;
RETERR(isc_str_tobuffer(wordbreak, target));
}
}
return (ISC_R_SUCCESS);
}
/*%
* State of a hex decoding process in progress.
*/
typedef struct {
int length; /*%< Desired length of binary data or -1 */
isc_buffer_t *target; /*%< Buffer for resulting binary data */
int digits; /*%< Number of buffered hex digits */
int val[2];
} hex_decode_ctx_t;
static inline void
hex_decode_init(hex_decode_ctx_t *ctx, int length, isc_buffer_t *target)
{
ctx->digits = 0;
ctx->length = length;
ctx->target = target;
}
static inline isc_result_t
hex_decode_char(hex_decode_ctx_t *ctx, int c) {
const char *s;
if ((s = strchr(hex, toupper(c))) == NULL)
return (ISC_R_BADHEX);
ctx->val[ctx->digits++] = (int)(s - hex);
if (ctx->digits == 2) {
unsigned char num;
num = (ctx->val[0] << 4) + (ctx->val[1]);
RETERR(isc_mem_tobuffer(ctx->target, &num, 1));
if (ctx->length >= 0) {
if (ctx->length == 0)
return (ISC_R_BADHEX);
else
ctx->length -= 1;
}
ctx->digits = 0;
}
return (ISC_R_SUCCESS);
}
static inline isc_result_t
hex_decode_finish(hex_decode_ctx_t *ctx) {
if (ctx->length > 0)
return (ISC_R_UNEXPECTEDEND);
if (ctx->digits != 0)
return (ISC_R_BADHEX);
return (ISC_R_SUCCESS);
}
isc_result_t
isc_hex_decodestring(const char *cstr, isc_buffer_t *target) {
hex_decode_ctx_t ctx;
hex_decode_init(&ctx, -1, target);
for (;;) {
int c = *cstr++;
if (c == '\0')
break;
if (c == ' ' || c == '\t' || c == '\n' || c== '\r')
continue;
RETERR(hex_decode_char(&ctx, c));
}
RETERR(hex_decode_finish(&ctx));
return (ISC_R_SUCCESS);
}
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