From: Florian Forster <octo@collectd.org>
Date: Sun, 12 May 2013 10:17:47 +0000 (+0200)
Subject: src/common.[ch]: Add the ssnprintf_alloc() function.
X-Git-Tag: collectd-5.4.0~44
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=80be251e335e8da43788ec50cec29bb38e11c24b;p=collectd.git

src/common.[ch]: Add the ssnprintf_alloc() function.
---

diff --git a/src/common.c b/src/common.c
index 79e4c02c..d963efa5 100644
--- a/src/common.c
+++ b/src/common.c
@@ -86,6 +86,47 @@ int ssnprintf (char *dest, size_t n, const char *format, ...)
 	return (ret);
 } /* int ssnprintf */
 
+char *ssnprintf_alloc (char const *format, ...) /* {{{ */
+{
+	char static_buffer[1024] = "";
+	char *alloc_buffer;
+	size_t alloc_buffer_size;
+	int status;
+	va_list ap;
+
+	/* Try printing into the static buffer. In many cases it will be
+	 * sufficiently large and we can simply return a strdup() of this
+	 * buffer. */
+	va_start (ap, format);
+	status = vsnprintf (static_buffer, sizeof (static_buffer), format, ap);
+	va_end (ap);
+	if (status < 0)
+		return (NULL);
+
+	/* "status" does not include the null byte. */
+	alloc_buffer_size = (size_t) (status + 1);
+	if (alloc_buffer_size <= sizeof (static_buffer))
+		return (strdup (static_buffer));
+
+	/* Allocate a buffer large enough to hold the string. */
+	alloc_buffer = malloc (alloc_buffer_size);
+	if (alloc_buffer == NULL)
+		return (NULL);
+	memset (alloc_buffer, 0, alloc_buffer_size);
+
+	/* Print again into this new buffer. */
+	va_start (ap, format);
+	status = vsnprintf (alloc_buffer, alloc_buffer_size, format, ap);
+	va_end (ap);
+	if (status < 0)
+	{
+		sfree (alloc_buffer);
+		return (NULL);
+	}
+
+	return (alloc_buffer);
+} /* }}} char *ssnprintf_alloc */
+
 char *sstrdup (const char *s)
 {
 	char *r;
diff --git a/src/common.h b/src/common.h
index 7c0d9369..317be8d1 100644
--- a/src/common.h
+++ b/src/common.h
@@ -56,7 +56,13 @@ struct rate_to_value_state_s
 typedef struct rate_to_value_state_s rate_to_value_state_t;
 
 char *sstrncpy (char *dest, const char *src, size_t n);
+
+__attribute__ ((format(printf,3,4)))
 int ssnprintf (char *dest, size_t n, const char *format, ...);
+
+__attribute__ ((format(printf,1,2)))
+char *ssnprintf_alloc (char const *format, ...);
+
 char *sstrdup(const char *s);
 void *smalloc(size_t size);
 char *sstrerror (int errnum, char *buf, size_t buflen);