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/*
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <debug.h>
#include <platform.h>
#include <stdarg.h>
static void string_print(char **s, size_t n, size_t *chars_printed,
const char *str)
{
while (*str != '\0') {
if (*chars_printed < n) {
*(*s) = *str;
(*s)++;
}
(*chars_printed)++;
str++;
}
}
static void unsigned_dec_print(char **s, size_t n, size_t *chars_printed,
unsigned int unum)
{
/* Enough for a 32-bit unsigned decimal integer (4294967295). */
char num_buf[10];
int i = 0;
unsigned int rem;
do {
rem = unum % 10U;
num_buf[i++] = '0' + rem;
unum /= 10U;
} while (unum > 0U);
while (--i >= 0) {
if (*chars_printed < n) {
*(*s) = num_buf[i];
(*s)++;
}
(*chars_printed)++;
}
}
/*******************************************************************
* Reduced snprintf to be used for Trusted firmware.
* The following type specifiers are supported:
*
* %d or %i - signed decimal format
* %s - string format
* %u - unsigned decimal format
*
* The function panics on all other formats specifiers.
*
* It returns the number of characters that would be written if the
* buffer was big enough. If it returns a value lower than n, the
* whole string has been written.
*******************************************************************/
int snprintf(char *s, size_t n, const char *fmt, ...)
{
va_list args;
int num;
unsigned int unum;
char *str;
size_t chars_printed = 0U;
if (n == 0U) {
/* There isn't space for anything. */
} else if (n == 1U) {
/* Buffer is too small to actually write anything else. */
*s = '\0';
n = 0U;
} else {
/* Reserve space for the terminator character. */
n--;
}
va_start(args, fmt);
while (*fmt != '\0') {
if (*fmt == '%') {
fmt++;
/* Check the format specifier. */
switch (*fmt) {
case 'i':
case 'd':
num = va_arg(args, int);
if (num < 0) {
if (chars_printed < n) {
*s = '-';
s++;
}
chars_printed++;
unum = (unsigned int)-num;
} else {
unum = (unsigned int)num;
}
unsigned_dec_print(&s, n, &chars_printed, unum);
break;
case 's':
str = va_arg(args, char *);
string_print(&s, n, &chars_printed, str);
break;
case 'u':
unum = va_arg(args, unsigned int);
unsigned_dec_print(&s, n, &chars_printed, unum);
break;
default:
/* Panic on any other format specifier. */
ERROR("snprintf: specifier with ASCII code '%d' not supported.",
*fmt);
plat_panic_handler();
assert(0); /* Unreachable */
}
fmt++;
continue;
}
if (chars_printed < n) {
*s = *fmt;
s++;
}
fmt++;
chars_printed++;
}
va_end(args);
if (n > 0U)
*s = '\0';
return (int)chars_printed;
}
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