darling-xnu/libsyscall/mach/string.c
2023-05-16 21:41:14 -07:00

123 lines
2.9 KiB
C

/*
* Copyright (c) 2010 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include "string.h"
static const char hex[] = "0123456789abcdef";
static int
_mach_strlen(const char *str)
{
const char *p;
for (p = str; p; p++) {
if (*p == '\0') {
return (int)(p - str);
}
}
/* NOTREACHED */
return 0;
}
static void
_mach_hex(char **buffer, int *length, unsigned long long n)
{
char buf[32];
char *cp = buf + sizeof(buf);
if (n) {
*--cp = '\0';
while (n) {
*--cp = hex[n & 0xf];
n >>= 4;
}
int width = _mach_strlen(cp);
while (width > 0 && length > 0) {
*(*buffer)++ = *cp++;
(*length)--;
width--;
}
}
}
int
_mach_vsnprintf(char *buffer, int length, const char *fmt, va_list ap)
{
int width, max = length;
char *out_ptr = buffer;
// we only ever write n-1 bytes so we can put a \0 at the end
length--;
while (length > 0 && *fmt) {
if (*fmt == '\0') {
break;
}
if (*fmt != '%') {
*(out_ptr++) = *(fmt++);
length--;
continue;
}
fmt++;
// only going to support a specific subset of sprintf flags
// namely %s, %x, with no padding modifiers
switch (*fmt++) {
case 's':
{
char *cp = va_arg(ap, char*);
width = _mach_strlen(cp);
while (width > 0 && length > 0) {
*(out_ptr++) = *(cp++);
width--;
length--;
}
break;
}
case 'x':
{
_mach_hex(&out_ptr, &length, va_arg(ap, unsigned int));
break;
}
}
}
if (max > 0) {
*out_ptr = '\0';
}
return max - (length + 1); /* don't include the final NULL in the return value */
}
int
_mach_snprintf(char *buffer, int length, const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = _mach_vsnprintf(buffer, length, fmt, ap);
va_end(ap);
return ret;
}