From a8b267540ecca0fa7d136078c7b84e2c6cd87e06 Mon Sep 17 00:00:00 2001 From: wm4 Date: Mon, 5 May 2014 23:55:06 +0200 Subject: common: change mp_snprintf_append semantics Make it more suitable for chaining. This means a function formatting a value to a string using a static buffer can work exactly like mp_snprintf_append itself. Also rename it to mp_snprintf_cat, because that's shorter. --- common/common.c | 15 +++++++++++---- common/common.h | 2 +- 2 files changed, 12 insertions(+), 5 deletions(-) (limited to 'common') diff --git a/common/common.c b/common/common.c index 6084176610..afab994d72 100644 --- a/common/common.c +++ b/common/common.c @@ -109,16 +109,23 @@ bool mp_rect_intersection(struct mp_rect *rc, const struct mp_rect *rc2) // This works like snprintf(), except that it starts writing the first output // character to str[strlen(str)]. This returns the number of characters the -// string would have assuming a large enough buffer, will make sure str is -// null-terminated, and will never write to str[size] or past. -int mp_snprintf_append(char *str, size_t size, const char *format, ...) +// string would have *appended* assuming a large enough buffer, will make sure +// str is null-terminated, and will never write to str[size] or past. +// Example: +// int example(char *buf, size_t buf_size, double num, char *str) { +// int n = 0; +// n += mp_snprintf_cat(buf, size, "%f", num); +// n += mp_snprintf_cat(buf, size, "%s", str); +// return n; } +// Note how this can be chained with functions similar in style. +int mp_snprintf_cat(char *str, size_t size, const char *format, ...) { size_t len = strnlen(str, size); assert(!size || len < size); // str with no 0-termination is not allowed int r; va_list ap; va_start(ap, format); - r = len + vsnprintf(str + len, size - len, format, ap); + r = vsnprintf(str + len, size - len, format, ap); va_end(ap); return r; } diff --git a/common/common.h b/common/common.h index f7362152c2..564d1f3ea0 100644 --- a/common/common.h +++ b/common/common.h @@ -77,7 +77,7 @@ struct mp_rect { void mp_rect_union(struct mp_rect *rc, const struct mp_rect *src); bool mp_rect_intersection(struct mp_rect *rc, const struct mp_rect *rc2); -int mp_snprintf_append(char *str, size_t size, const char *format, ...) +int mp_snprintf_cat(char *str, size_t size, const char *format, ...) PRINTF_ATTRIBUTE(3, 4); struct bstr; -- cgit v1.2.3