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Commit	Line	Data
	1	/*
	2	* Copyright (c) 2010 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include "string.h"
	30
	31	static const char hex[] = "0123456789abcdef";
	32
	33	static int
	34	_mach_strlen(const char *str)
	35	{
	36	const char *p;
	37	for (p = str; p; p++) {
	38	if (*p == '\0') {
	39	return (int)(p - str);
	40	}
	41	}
	42	/* NOTREACHED */
	43	return 0;
	44	}
	45
	46	static void
	47	_mach_hex(char *buffer, int length, unsigned long long n)
	48	{
	49	char buf[32];
	50	char *cp = buf + sizeof(buf);
	51
	52	if (n) {
	53	*--cp = '\0';
	54	while (n) {
	55	*--cp = hex[n & 0xf];
	56	n >>= 4;
	57	}
	58
	59	int width = _mach_strlen(cp);
	60	while (width > 0 && length > 0) {
	61	(buffer)++ = *cp++;
	62	(*length)--;
	63	width--;
	64	}
	65	}
	66	}
	67
	68	int
	69	_mach_vsnprintf(char buffer, int length, const char fmt, va_list ap)
	70	{
	71	int width, max = length;
	72	char *out_ptr = buffer;
	73
	74	// we only ever write n-1 bytes so we can put a \0 at the end
	75	length--;
	76	while (length > 0 && *fmt) {
	77	if (*fmt == '\0') {
	78	break;
	79	}
	80	if (*fmt != '%') {
	81	(out_ptr++) = (fmt++);
	82	length--;
	83	continue;
	84	}
	85	fmt++;
	86	// only going to support a specific subset of sprintf flags
	87	// namely %s, %x, with no padding modifiers
	88	switch (*fmt++) {
	89	case 's':
	90	{
	91	char cp = va_arg(ap, char);
	92	width = _mach_strlen(cp);
	93	while (width > 0 && length > 0) {
	94	(out_ptr++) = (cp++);
	95	width--;
	96	length--;
	97	}
	98	break;
	99	}
	100	case 'x':
	101	{
	102	_mach_hex(&out_ptr, &length, va_arg(ap, unsigned int));
	103	break;
	104	}
	105	}
	106	}
	107	if (max > 0) {
	108	*out_ptr = '\0';
	109	}
	110	return max - (length + 1); /* don't include the final NULL in the return value */
	111	}
	112
	113	int
	114	_mach_snprintf(char buffer, int length, const char fmt, ...)
	115	{
	116	int ret;
	117	va_list ap;
	118	va_start(ap, fmt);
	119	ret = _mach_vsnprintf(buffer, length, fmt, ap);
	120	va_end(ap);
	121	return ret;
	122	}