diff options
| -rw-r--r-- | lib/libc/include/stdio.h | 3 | ||||
| -rw-r--r-- | lib/libc/src/stdio/vsnprintf.c | 82 |
2 files changed, 85 insertions, 0 deletions
diff --git a/lib/libc/include/stdio.h b/lib/libc/include/stdio.h index b19230c..e701de0 100644 --- a/lib/libc/include/stdio.h +++ b/lib/libc/include/stdio.h @@ -31,6 +31,7 @@ #define _STDIO_H #include <stddef.h> +#include <stdarg.h> #define EOF (int)-1 @@ -64,4 +65,6 @@ int puts(const char *s); int fflush(FILE *stream); int fclose(FILE *stream); +int vsnprintf(char *s, size_t size, const char *fmt, va_list ap); + #endif /* !_STDIO_H */ diff --git a/lib/libc/src/stdio/vsnprintf.c b/lib/libc/src/stdio/vsnprintf.c new file mode 100644 index 0000000..6cc0a04 --- /dev/null +++ b/lib/libc/src/stdio/vsnprintf.c @@ -0,0 +1,82 @@ +/* + * Copyright (c) 2023-2024 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> + +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, off = 0; + ssize_t num = 0; + char c, c1; + const char *tmp_str; + + while (off < (size - 1)) { + while (*fmt && *fmt != '%') { + printc(s, size, &off, *fmt++); + } + + if (*(fmt)++ == '\0' || off == size - 1) { + return off; + } + + c = *fmt++; + switch (c) { + case 'c': + c1 = (char)va_arg(ap, int); + printc(s, size, &off, c1); + break; + case 's': + tmp_str = va_arg(ap, const char *); + printstr(s, size, &off, tmp_str); + break; + } + } + + return 0; +} |