* RNA: utility function to retrieve strings. It will use a fixed

  size buffer if it's big enough, and otherwise allocate memory.
* Added BLI_dynstr_appendf() to construct strings easily in printf
  style, this should make it easier to construct menu strings for
  example.

1 files changed, 56 insertions, 3 deletions

diff --git a/source/blender/blenlib/intern/BLI_dynstr.c b/source/blender/blenlib/intern/BLI_dynstr.c
index 43c80dd24f0..1c539af2957 100644
--- a/source/blender/blenlib/intern/BLI_dynstr.c
+++ b/source/blender/blenlib/intern/BLI_dynstr.c
@@ -28,6 +28,8 @@
  * Dynamically sized string ADT
  */
 
+#include <stdarg.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -35,8 +37,10 @@
 #include "BLI_blenlib.h"
 #include "BLI_dynstr.h"
 
-#ifdef HAVE_CONFIG_H
-#include <config.h>
+#ifdef _WIN32
+#ifndef vsnprintf
+#define vsnprintf _vsnprintf
+#endif
 #endif
 
 /***/
@@ -63,7 +67,7 @@ DynStr *BLI_dynstr_new(void) {
 	return ds;
 }
 
-void BLI_dynstr_append(DynStr *ds, char *cstr) {
+void BLI_dynstr_append(DynStr *ds, const char *cstr) {
 	DynStrElem *dse= malloc(sizeof(*dse));
 	int cstrlen= strlen(cstr);
 	
@@ -79,6 +83,55 @@ void BLI_dynstr_append(DynStr *ds, char *cstr) {
 	ds->curlen+= cstrlen;
 }
 
+void BLI_dynstr_appendf(DynStr *ds, const char *format, ...)
+{
+	va_list args;
+	char *message, fixedmessage[256];
+	int len= 256, maxlen= 65536, retval;
+
+	while(1) {
+		if(len == sizeof(fixedmessage))
+			message= fixedmessage;
+		else
+			message= MEM_callocN(sizeof(char)*len+1, "BLI_dynstr_appendf");
+
+		va_start(args, format);
+		retval= vsnprintf(message, len, format, args);
+		va_end(args);
+
+		if(retval == -1) {
+			/* -1 means not enough space, but on windows it may also mean
+			 * there is a formatting error, so we impose a maximum length */
+			if(message != fixedmessage)
+				MEM_freeN(message);
+			message= NULL;
+
+			len *= 2;
+			if(len > maxlen) {
+				fprintf(stderr, "BLI_dynstr_append text too long or format error.\n");
+				break;
+			}
+		}
+		else if(retval > len) {
+			/* in C99 the actual length required is returned */
+			if(message != fixedmessage)
+				MEM_freeN(message);
+			message= NULL;
+
+			len= retval;
+		}
+		else
+			break;
+	}
+
+	if(message) {
+		BLI_dynstr_append(ds, message);
+
+		if(message != fixedmessage)
+			MEM_freeN(message);
+	}
+}
+
 int BLI_dynstr_get_len(DynStr *ds) {
 	return ds->curlen;
 }