| Ambroise Vincent | 4128f9f | 2019-02-11 13:34:41 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved. |
| 3 | * |
| 4 | * SPDX-License-Identifier: BSD-3-Clause |
| 5 | */ |
| 6 | |
| 7 | #include <assert.h> |
| 8 | #include <stdarg.h> |
| 9 | |
| 10 | #include <common/debug.h> |
| 11 | #include <plat/common/platform.h> |
| 12 | |
| 13 | static void string_print(char **s, size_t n, size_t *chars_printed, |
| 14 | const char *str) |
| 15 | { |
| 16 | while (*str != '\0') { |
| 17 | if (*chars_printed < n) { |
| 18 | *(*s) = *str; |
| 19 | (*s)++; |
| 20 | } |
| 21 | |
| 22 | (*chars_printed)++; |
| 23 | str++; |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | static void unsigned_dec_print(char **s, size_t n, size_t *chars_printed, |
| 28 | unsigned int unum) |
| 29 | { |
| 30 | /* Enough for a 32-bit unsigned decimal integer (4294967295). */ |
| 31 | char num_buf[10]; |
| 32 | int i = 0; |
| 33 | unsigned int rem; |
| 34 | |
| 35 | do { |
| 36 | rem = unum % 10U; |
| 37 | num_buf[i++] = '0' + rem; |
| 38 | unum /= 10U; |
| 39 | } while (unum > 0U); |
| 40 | |
| 41 | while (--i >= 0) { |
| 42 | if (*chars_printed < n) { |
| 43 | *(*s) = num_buf[i]; |
| 44 | (*s)++; |
| 45 | } |
| 46 | |
| 47 | (*chars_printed)++; |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | /******************************************************************* |
| 52 | * Reduced snprintf to be used for Trusted firmware. |
| 53 | * The following type specifiers are supported: |
| 54 | * |
| 55 | * %d or %i - signed decimal format |
| 56 | * %s - string format |
| 57 | * %u - unsigned decimal format |
| 58 | * |
| 59 | * The function panics on all other formats specifiers. |
| 60 | * |
| 61 | * It returns the number of characters that would be written if the |
| 62 | * buffer was big enough. If it returns a value lower than n, the |
| 63 | * whole string has been written. |
| 64 | *******************************************************************/ |
| 65 | int snprintf(char *s, size_t n, const char *fmt, ...) |
| 66 | { |
| 67 | va_list args; |
| 68 | int num; |
| 69 | unsigned int unum; |
| 70 | char *str; |
| 71 | size_t chars_printed = 0U; |
| 72 | |
| 73 | if (n == 0U) { |
| 74 | /* There isn't space for anything. */ |
| 75 | } else if (n == 1U) { |
| 76 | /* Buffer is too small to actually write anything else. */ |
| 77 | *s = '\0'; |
| 78 | n = 0U; |
| 79 | } else { |
| 80 | /* Reserve space for the terminator character. */ |
| 81 | n--; |
| 82 | } |
| 83 | |
| 84 | va_start(args, fmt); |
| 85 | while (*fmt != '\0') { |
| 86 | |
| 87 | if (*fmt == '%') { |
| 88 | fmt++; |
| 89 | /* Check the format specifier. */ |
| 90 | switch (*fmt) { |
| 91 | case 'i': |
| 92 | case 'd': |
| 93 | num = va_arg(args, int); |
| 94 | |
| 95 | if (num < 0) { |
| 96 | if (chars_printed < n) { |
| 97 | *s = '-'; |
| 98 | s++; |
| 99 | } |
| 100 | chars_printed++; |
| 101 | |
| 102 | unum = (unsigned int)-num; |
| 103 | } else { |
| 104 | unum = (unsigned int)num; |
| 105 | } |
| 106 | |
| 107 | unsigned_dec_print(&s, n, &chars_printed, unum); |
| 108 | break; |
| 109 | case 's': |
| 110 | str = va_arg(args, char *); |
| 111 | string_print(&s, n, &chars_printed, str); |
| 112 | break; |
| 113 | case 'u': |
| 114 | unum = va_arg(args, unsigned int); |
| 115 | unsigned_dec_print(&s, n, &chars_printed, unum); |
| 116 | break; |
| 117 | default: |
| 118 | /* Panic on any other format specifier. */ |
| 119 | ERROR("snprintf: specifier with ASCII code '%d' not supported.", |
| 120 | *fmt); |
| 121 | plat_panic_handler(); |
| 122 | assert(0); /* Unreachable */ |
| 123 | } |
| 124 | fmt++; |
| 125 | continue; |
| 126 | } |
| 127 | |
| 128 | if (chars_printed < n) { |
| 129 | *s = *fmt; |
| 130 | s++; |
| 131 | } |
| 132 | |
| 133 | fmt++; |
| 134 | chars_printed++; |
| 135 | } |
| 136 | |
| 137 | va_end(args); |
| 138 | |
| 139 | if (n > 0U) |
| 140 | *s = '\0'; |
| 141 | |
| 142 | return (int)chars_printed; |
| 143 | } |