v.out.ogr: sort formats

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@48937 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.out.ogr/list.c

@@ -1,38 +1,64 @@
 #include "local_proto.h"
 
+static int cmp(const void *, const void *);
+
 /* to print available drivers in help text */
 char *OGR_list_write_drivers(void)
 {
-    int drn, i;
+    int i, count;
+    size_t len;
     OGRSFDriverH Ogr_driver;
     char buf[2000];
+    
+    char **list, *ret;
 
-    char OGRdrivers[2000];
-
-    OGRdrivers[0] = '\0';
-
+    list = NULL;
+    count = len = 0;
+    
     /* Open OGR DSN */
     OGRRegisterAll();
     G_debug(2, "driver count = %d", OGRGetDriverCount());
-    drn = 0;
     for (i = 0; i < OGRGetDriverCount(); i++) {
 	/* only fetch read/write drivers */
 	if (!OGR_Dr_TestCapability(OGRGetDriver(i), ODrCCreateDataSource))
 	    continue;
 	
-	if (drn)
-	    strcat(OGRdrivers, ",");
-	
 	Ogr_driver = OGRGetDriver(i);
 	G_debug(2, "driver %d/%d : %s", i, OGRGetDriverCount(),
 		OGR_Dr_GetName(Ogr_driver));
+	
+	list = G_realloc(list, (count + 1) * sizeof(char *));
+
 	/* chg white space to underscore in OGR driver names */
 	sprintf(buf, "%s", OGR_Dr_GetName(Ogr_driver));
 	G_strchg(buf, ' ', '_');
-	strcat(OGRdrivers, buf);
-	drn++;
+	list[count++] = G_store(buf);
+	len += strlen(buf) + 1; /* + ',' */
     }
-    G_debug(2, "all drivers: %s", OGRdrivers);
 
-    return G_store(OGRdrivers);
+    qsort(list, count, sizeof(char *), cmp);
+
+    if (len > 0) {
+	ret = G_malloc((len + 1) * sizeof(char)); /* \0 */
+	*ret = '\0';
+	for (i = 0; i < count; i++) {
+	    if (i > 0)
+		strcat(ret, ",");
+	    strcat(ret, list[i]);
+	    G_free(list[i]);
+	}
+	G_free(list);
+    }
+    else {
+	ret = G_store("");
+    }
+    
+    G_debug(2, "all drivers: %s", ret);
+
+    return ret;
+}
+
+int cmp(const void *a, const void *b) 
+{
+    return (strcmp(*(char **)a, *(char **)b));
 }