Add vasprintf() and asprintf()

The new utils.c functions vasprintf() and asprintf() are analogs to
sprintf() and vsprintf(). However, instead of requiring a buffer that is
large enough to hold the output data, the functions allocate a string
and return a pointer to it.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

2 files changed, 40 insertions, 0 deletions

diff --git a/src/calcurse.h b/src/calcurse.h
index e593ff0..887e224 100644
--- a/src/calcurse.h
+++ b/src/calcurse.h
@@ -1051,6 +1051,8 @@ void print_recur_apoint(const char *, long, unsigned,
 			struct recur_apoint *);
 void print_recur_event(const char *, long, struct recur_event *);
 void print_todo(const char *, struct todo *);
+int vasprintf(char **, const char *, va_list);
+int asprintf(char **, const char *, ...);
 
 /* vars.c */
 extern int col, row;
diff --git a/src/utils.c b/src/utils.c
index 02839c3..c675518 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1473,3 +1473,41 @@ void print_todo(const char *format, struct todo *todo)
 		}
 	}
 }
+
+#define VASPRINTF_INITIAL_BUFSIZE 128
+
+int
+vasprintf(char **str, const char *format, va_list ap)
+{
+	va_list ap2;
+	int n;
+
+	va_copy(ap2, ap);
+
+	*str = mem_malloc(VASPRINTF_INITIAL_BUFSIZE);
+	n = vsnprintf(*str, VASPRINTF_INITIAL_BUFSIZE, format, ap);
+	if (n >= VASPRINTF_INITIAL_BUFSIZE) {
+		*str = mem_realloc(*str, 1, n + 1);
+		n = vsnprintf(*str, n + 1, format, ap2);
+	}
+
+	if (n < 0) {
+		mem_free(*str);
+		*str = NULL;
+	}
+
+	return n;
+}
+
+int
+asprintf(char **str, const char *format, ...)
+{
+	va_list	ap;
+	int n;
+
+	va_start(ap, format);
+	n = vasprintf(str, format, ap);
+	va_end(ap);
+
+	return n;
+}