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Commit	Line	Data
	1	/*
	2	* This file is part of DisOrder
	3	* Copyright (C) 2004, 2005 Richard Kettlewell
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
	18	* USA
	19	*/
	20	/** @file lib/hex.c @brief Hexadecimal encoding and decoding */
	21
	22	#include <config.h>
	23	#include "types.h"
	24
	25	#include <stdio.h>
	26	#include <string.h>
	27
	28	#include "hex.h"
	29	#include "mem.h"
	30	#include "log.h"
	31
	32	/** @brief Convert a byte sequence to hex
	33	* @param ptr Pointer to first byte
	34	* @param n Number of bytes
	35	* @return Allocated string containing hexdump
	36	*/
	37	char hex(const uint8_t ptr, size_t n) {
	38	char buf = xmalloc_noptr(n 2 + 1), *p = buf;
	39
	40	while(n-- > 0)
	41	p += sprintf(p, "%02x", (unsigned)*ptr++);
	42	*p = 0;
	43	return buf;
	44	}
	45
	46	/** @brief Convert a character to its value as a hex digit
	47	* @param c Character code
	48	* @return Value has hex digit or -1
	49	*
	50	* The 'q' stands for 'quiet' - this function does not report errors.
	51	*/
	52	int unhexdigitq(int c) {
	53	switch(c) {
	54	case '0': return 0;
	55	case '1': return 1;
	56	case '2': return 2;
	57	case '3': return 3;
	58	case '4': return 4;
	59	case '5': return 5;
	60	case '6': return 6;
	61	case '7': return 7;
	62	case '8': return 8;
	63	case '9': return 9;
	64	case 'a': case 'A': return 10;
	65	case 'b': case 'B': return 11;
	66	case 'c': case 'C': return 12;
	67	case 'd': case 'D': return 13;
	68	case 'e': case 'E': return 14;
	69	case 'f': case 'F': return 15;
	70	default: return -1;
	71	}
	72	}
	73
	74	/** @brief Convert a character to its value as a hex digit
	75	* @param c Character code
	76	* @return Value has hex digit or -1
	77	*
	78	* If the character is not a valid hex digit then an error is logged.
	79	* See @ref unhexdigitq() if that is a problem.
	80	*/
	81	int unhexdigit(int c) {
	82	int d;
	83
	84	if((d = unhexdigitq(c)) < 0) error(0, "invalid hex digit");
	85	return d;
	86	}
	87
	88	/** @brief Convert a hex string to bytes
	89	* @param s Pointer to hex string
	90	* @param np Where to store byte string length or NULL
	91	* @return Allocated buffer, or 0
	92	*
	93	* @p s should point to a 0-terminated string containing an even number
	94	* of hex digits. They are converted to bytes and returned via the return
	95	* value and optionally the length via @p np.
	96	*
	97	* On any error a message is logged and a null pointer is returned.
	98	*/
	99	uint8_t unhex(const char s, size_t *np) {
	100	size_t l;
	101	uint8_t buf, p;
	102	int d1, d2;
	103
	104	if((l = strlen(s)) & 1) {
	105	error(0, "hex string has odd length");
	106	return 0;
	107	}
	108	p = buf = xmalloc_noptr(l / 2);
	109	while(*s) {
	110	if((d1 = unhexdigit(*s++)) < 0) return 0;
	111	if((d2 = unhexdigit(*s++)) < 0) return 0;
	112	p++ = d1 16 + d2;
	113	}
	114	if(np)
	115	*np = l / 2;
	116	return buf;
	117	}
	118
	119	/*
	120	Local Variables:
	121	c-basic-offset:2
	122	comment-column:40
	123	End:
	124	*/