diff options
Diffstat (limited to 'lib/libc')
| -rw-r--r-- | lib/libc/include/stdio.h | 1 | ||||
| -rw-r--r-- | lib/libc/src/stdio/vsnprintf.c | 135 |
2 files changed, 136 insertions, 0 deletions
diff --git a/lib/libc/include/stdio.h b/lib/libc/include/stdio.h index cdb9c14..460b674 100644 --- a/lib/libc/include/stdio.h +++ b/lib/libc/include/stdio.h @@ -75,6 +75,7 @@ __BEGIN_DECLS size_t fread(void *__restrict ptr, size_t size, size_t n, FILE *__restrict stream); size_t fwrite(const void *__restrict ptr, size_t size, size_t n, FILE *__restrict stream); +int vsnprintf(char *s, size_t size, const char *fmt, va_list ap); int fputc(int c, FILE *stream); int putchar(int c); diff --git a/lib/libc/src/stdio/vsnprintf.c b/lib/libc/src/stdio/vsnprintf.c new file mode 100644 index 0000000..c122459 --- /dev/null +++ b/lib/libc/src/stdio/vsnprintf.c @@ -0,0 +1,135 @@ +/* + * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <stdio.h> +#include <stddef.h> +#include <string.h> + +/* TODO FIXME: Use stdarg.h */ +#define __va_arg(ap, type) __builtin_va_arg(ap, type) + +static inline void +printc(char *buf, size_t size, size_t *off, char c) +{ + if (*off < size - 1) { + buf[(*off)++] = c; + } + buf[*off] = 0; +} + +static void +printstr(char *buf, size_t size, size_t *off, const char *s) +{ + while (*off < size - 1 && *s != '\0') { + buf[(*off)++] = *(s)++; + } + buf[*off] = 0; +} + +int +vsnprintf(char *s, size_t size, const char *fmt, va_list ap) +{ + size_t tmp_len, num_len, off = 0; + ssize_t num = 0; + char c, c1, num_buf[256] = {0}; + const char *tmp_str; + uint8_t pad_width = 0; + + while (off < (size - 1)) { + while (*fmt && *fmt != '%') { + printc(s, size, &off, *fmt++); + } + if (*(fmt)++ == '\0' || off == size - 1) { + return off; + } + + /* + * Handle a case where we have "%0N". For example: + * "%04d" + */ + if (*fmt == '0') { + ++fmt; + while (*fmt >= '0' && *fmt <= '9') { + pad_width = pad_width * 10 + (*fmt - '0'); + ++fmt; + } + } + + c = *fmt++; + switch (c) { + case 'c': + c1 = (char )__va_arg(ap, int); + printc(s, size, &off, c1); + break; + case 'd': + num = __va_arg(ap, int); + itoa(num, num_buf, 10); + + if (pad_width > 0) { + num_len = strlen(num_buf); + for (size_t i = num_len; i < pad_width; ++i) + printc(s, size, &off, '0'); + } + printstr(s, size, &off, num_buf); + break; + case 'p': + num = __va_arg(ap, uint64_t); + itoa(num, num_buf, 16); + tmp_len = strlen(num_buf); + + /* Add '0x' prefix */ + printc(s, size, &off, '0'); + printc(s, size, &off, 'x'); + /* + * Now we pad this. + * + * XXX TODO: This assumes 64-bits, should be + * cleaned up. + */ + for (size_t i = 0; i < 18 - tmp_len; ++i) { + printc(s, size, &off, '0'); + } + printstr(s, size, &off, num_buf + 2); + break; + case 'x': + num = __va_arg(ap, uint64_t); + itoa(num, num_buf, 16); + tmp_len = strlen(num_buf); + printstr(s, size, &off, num_buf + 2); + break; + case 's': + tmp_str = __va_arg(ap, const char *); + printstr(s, size, &off, tmp_str); + break; + } + } + + return 0; +} |