Bugfix #18637

Sorting of files didn't take numbers into account propertly, so it
ordered files like;

10.jpg
300.jpg
89.jpg
9.jpg

Quite simple to solve, almost moved report to the 'todo', but too
fun to leave this. :)

function name is BLI_natstrcmp() "natural string compare".

3 files changed, 51 insertions, 1 deletions

diff --git a/source/blender/blenlib/BLI_blenlib.h b/source/blender/blenlib/BLI_blenlib.h
index 13d5b5fe829..c131dd93c72 100644
--- a/source/blender/blenlib/BLI_blenlib.h
+++ b/source/blender/blenlib/BLI_blenlib.h
@@ -387,6 +387,7 @@ void BLI_setInterruptCallBack(int (*f)(void));
 char *BLI_strcasestr(const char *s, const char *find);
 int BLI_strcasecmp(const char *s1, const char *s2);
 int BLI_strncasecmp(const char *s1, const char *s2, int n);
+int BLI_natstrcmp(const char *s1, const char *s2);
 void BLI_timestr(double _time, char *str); /* time var is global */
 
 /** 
diff --git a/source/blender/blenlib/intern/storage.c b/source/blender/blenlib/intern/storage.c
index 8ba03ad1343..088b5e40a51 100644
--- a/source/blender/blenlib/intern/storage.c
+++ b/source/blender/blenlib/intern/storage.c
@@ -153,7 +153,7 @@ int BLI_compare(struct direntry *entry1, struct direntry *entry2)
 	if( strcmp(entry2->relname, ".")==0 ) return (1);
 	if( strcmp(entry1->relname, "..")==0 ) return (-1);
 	
-	return (BLI_strcasecmp(entry1->relname,entry2->relname));
+	return (BLI_natstrcmp(entry1->relname,entry2->relname));
 }
 
 
diff --git a/source/blender/blenlib/intern/util.c b/source/blender/blenlib/intern/util.c
index 013b9e0bb1b..842ebc4c0a9 100644
--- a/source/blender/blenlib/intern/util.c
+++ b/source/blender/blenlib/intern/util.c
@@ -1985,6 +1985,55 @@ int BLI_strncasecmp(const char *s1, const char *s2, int n) {
 	return 0;
 }
 
+/* natural string compare, keeping numbers in order */
+int BLI_natstrcmp(const char *s1, const char *s2)
+{
+	int d1= 0, d2= 0;
+	
+	/* if both chars are numeric, to a strtol().
+	   then increase string deltas as long they are 
+	   numeric, else do a tolower and char compare */
+	
+	while(1) {
+		char c1 = tolower(s1[d1]);
+		char c2 = tolower(s2[d2]);
+		
+		if( isdigit(c1) && isdigit(c2) ) {
+			int val1, val2;
+			
+			val1= (int)strtol(s1+d1, (char **)NULL, 10);
+			val2= (int)strtol(s2+d2, (char **)NULL, 10);
+			
+			if (val1<val2) {
+				return -1;
+			} else if (val1>val2) {
+				return 1;
+			}
+			d1++;
+			while( isdigit(s1[d1]) )
+				d1++;
+			d2++;
+			while( isdigit(s2[d2]) )
+				d2++;
+			
+			c1 = tolower(s1[d1]);
+			c2 = tolower(s2[d2]);
+		}
+		
+		if (c1<c2) {
+			return -1;
+		} else if (c1>c2) {
+			return 1;
+		} else if (c1==0) {
+			break;
+		}
+		d1++;
+		d2++;
+	}
+	
+}
+
+
 
 #ifdef WITH_ICONV
 #include "iconv.h"