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author | June McEnroe <june@causal.agency> | 2021-06-07 00:08:59 -0400 |
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committer | June McEnroe <june@causal.agency> | 2021-06-09 11:41:15 -0400 |
commit | 5c3cd59af6550d6f8d74487c1e46cdb0b171ff7d (patch) | |
tree | 3851069ae3d57ef7f6fc5f09558d3669f27c1acf | |
parent | OpenBSD: pledge minimum promises from the start (diff) | |
download | catgirl-5c3cd59af6550d6f8d74487c1e46cdb0b171ff7d.tar.gz catgirl-5c3cd59af6550d6f8d74487c1e46cdb0b171ff7d.zip |
Add seprintf
Based on seprint(2) from Plan 9. I'm not sure if my return value exactly matches Plan 9's in the case of truncation. seprint(2) is described only as returning a pointer to the terminating '\0', but if it does so even in the case of truncation, it is awkward for the caller to detect. This implementation returns end in the truncation case, so that (ptr == end) indicates truncation.
-rw-r--r-- | chat.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/chat.h b/chat.h index e48799c..e9bee8b 100644 --- a/chat.h +++ b/chat.h @@ -44,6 +44,18 @@ typedef unsigned uint; typedef unsigned char byte; +static inline char *seprintf(char *ptr, char *end, const char *fmt, ...) + __attribute__((format(printf, 3, 4))); +static inline char *seprintf(char *ptr, char *end, const char *fmt, ...) { + va_list ap; + va_start(ap, fmt); + int n = vsnprintf(ptr, end - ptr, fmt, ap); + va_end(ap); + if (n < 0) return NULL; + ptr += n; + return (ptr > end ? end : ptr); +} + struct Cat { char *buf; size_t cap; |