librb: add rb_snprintf_try_append

For when it might fit, or it might not.
This commit is contained in:
Simon Arlott 2017-07-30 17:04:06 +01:00
parent 8573c3409e
commit e5c434a2df
No known key found for this signature in database
GPG key ID: C8975F2043CA5D24
3 changed files with 38 additions and 7 deletions

View file

@ -36,13 +36,8 @@ char *rb_strcasestr(const char *s, const char *find);
size_t rb_strlcpy(char *dst, const char *src, size_t siz); size_t rb_strlcpy(char *dst, const char *src, size_t siz);
size_t rb_strlcat(char *dst, const char *src, size_t siz); size_t rb_strlcat(char *dst, const char *src, size_t siz);
size_t rb_strnlen(const char *s, size_t count); size_t rb_strnlen(const char *s, size_t count);
int rb_snprintf_append(char *str, size_t len, const char *format, ...) AFP(3,4);
#ifdef __GNUC__ int rb_snprintf_try_append(char *str, size_t len, const char *format, ...) AFP(3,4);
int rb_snprintf_append(char *str, size_t len, const char *format, ...)
__attribute__ ((format(printf, 3, 4)));
#else
int rb_snprintf_append(char *str, const size_t size, const char *, ...);
#endif
char *rb_basename(const char *); char *rb_basename(const char *);
char *rb_dirname(const char *); char *rb_dirname(const char *);

View file

@ -161,6 +161,7 @@ rb_setup_fd
rb_setup_ssl_server rb_setup_ssl_server
rb_sleep rb_sleep
rb_snprintf_append rb_snprintf_append
rb_snprintf_try_append
rb_socket rb_socket
rb_socketpair rb_socketpair
rb_spawn_process rb_spawn_process

View file

@ -324,6 +324,41 @@ rb_snprintf_append(char *str, size_t len, const char *format, ...)
return (orig_len + append_len); return (orig_len + append_len);
} }
/*
* rb_snprintf_try_append()
* appends snprintf formatted string to the end of the buffer but not
* exceeding len
* returns -1 if there isn't enough space for the whole string to fit
*/
int
rb_snprintf_try_append(char *str, size_t len, const char *format, ...)
{
if(len == 0)
return -1;
int orig_len = strlen(str);
if((int)len < orig_len) {
str[len - 1] = '\0';
return -1;
}
va_list ap;
va_start(ap, format);
int append_len = vsnprintf(str + orig_len, len - orig_len, format, ap);
va_end(ap);
if (append_len < 0)
return append_len;
if (orig_len + append_len > (int)(len - 1)) {
str[orig_len] = '\0';
return -1;
}
return (orig_len + append_len);
}
/* rb_basename /* rb_basename
* *
* input - * input -