[libexif-cvs] libexif/libexif exif-data.c, 1.122, 1.123 exif-tag.c, 1.58, 1.59

[Dan F. <dfa...@us...>]

Update of /cvsroot/libexif/libexif/libexif
In directory ddv4jf1.ch3.sourceforge.com:/tmp/cvs-serv26924/libexif

Modified Files:
	exif-data.c exif-tag.c 
Log Message:
Improved tag table lookup performance by optimally ordering IFD
search and aborting searches early if the tag is not found.


Index: exif-tag.c
===================================================================
RCS file: /cvsroot/libexif/libexif/libexif/exif-tag.c,v
retrieving revision 1.58
retrieving revision 1.59
diff -u -p -d -r1.58 -r1.59
--- exif-tag.c	15 Oct 2009 06:15:17 -0000	1.58
+++ exif-tag.c	27 Oct 2009 00:41:43 -0000	1.59
@@ -45,7 +45,8 @@
  * When there are such duplicate entries, there must be no overlap in their
  * support levels.
  * The entries MUST be sorted in tag order.
- * The name and title are mandatory, but the description may be NULL.
+ * The name and title are mandatory, but the description may be an empty
+ * string. None of the entries may be NULL except the final array terminator.
  */
 static const struct TagEntry {
 	/*! Tag ID. There may be duplicate tags when the same number is used for
@@ -945,8 +946,14 @@ exif_tag_get_name_in_ifd (ExifTag tag, E
 	first = exif_tag_table_first(tag);
 	if (first < 0)
 		return NULL;
-	for (i = first; ExifTagTable[i].name; i++)
-		if ((ExifTagTable[i].tag == tag) && RECORDED) break;
+
+	for (i = first; ExifTagTable[i].name; i++) {
+		if (ExifTagTable[i].tag == tag) {
+		   if (RECORDED)
+			   break;
+		} else
+			return NULL; /* Recorded tag not found in the table */
+	}
 	return ExifTagTable[i].name;
 }
 
@@ -969,8 +976,14 @@ exif_tag_get_title_in_ifd (ExifTag tag, 
 	first = exif_tag_table_first(tag);
 	if (first < 0)
 		return NULL;
-	for (i = first; ExifTagTable[i].title; i++)
-		if ((ExifTagTable[i].tag == tag) && RECORDED) break;
+
+	for (i = first; ExifTagTable[i].name; i++) {
+		if (ExifTagTable[i].tag == tag) {
+		   if (RECORDED)
+			   break;
+		} else
+			return NULL; /* Recorded tag not found in the table */
+	}
 	return _(ExifTagTable[i].title);
 }
 
@@ -993,14 +1006,19 @@ exif_tag_get_description_in_ifd (ExifTag
 	first = exif_tag_table_first(tag);
 	if (first < 0)
 		return NULL;
-	for (i = 0; ExifTagTable[i].description; i++)
-		if ((ExifTagTable[i].tag == tag) && RECORDED) {
-			/* GNU gettext acts strangely when given an empty string */
-			if (!*ExifTagTable[i].description)
-				return "";
-			return _(ExifTagTable[i].description);
-		}
-	return NULL;
+
+	for (i = 0; ExifTagTable[i].name; i++) {
+		if (ExifTagTable[i].tag == tag) {
+			if (RECORDED)
+				break;
+		} else
+			return NULL; /* Recorded tag not found in the table */
+	}
+
+	/* GNU gettext acts strangely when given an empty string */
+	if (!ExifTagTable[i].description || !*ExifTagTable[i].description)
+		return "";
+	return _(ExifTagTable[i].description);
 }
 
 
@@ -1014,10 +1032,11 @@ typedef const char * (*get_stuff_func) (
 static const char *
 exif_tag_get_stuff (ExifTag tag, get_stuff_func func)
 {
+	/* Search IFDs in this order, in decreasing order of number of valid tags */
 	static const ExifIfd ifds[EXIF_IFD_COUNT] = {
+		EXIF_IFD_EXIF,
 		EXIF_IFD_0,
 		EXIF_IFD_1,
-		EXIF_IFD_EXIF,
 		EXIF_IFD_INTEROPERABILITY,
 		EXIF_IFD_GPS
 	};
@@ -1084,6 +1103,7 @@ get_support_level_in_ifd (ExifTag tag, E
 	int first = exif_tag_table_first(tag);
 	if (first < 0)
 		return EXIF_SUPPORT_LEVEL_NOT_RECORDED;
+
 	for (i = first; ExifTagTable[i].name; i++) {
 		if (ExifTagTable[i].tag == tag) {
 			const ExifSupportLevel supp = ExifTagTable[i].esl[ifd][t];

Index: exif-data.c
===================================================================
RCS file: /cvsroot/libexif/libexif/libexif/exif-data.c,v
retrieving revision 1.122
retrieving revision 1.123
diff -u -p -d -r1.122 -r1.123
--- exif-data.c	15 Oct 2009 07:32:54 -0000	1.122
+++ exif-data.c	27 Oct 2009 00:41:43 -0000	1.123
@@ -414,7 +414,8 @@ exif_data_load_data_content (ExifData *d
 			 * specific IFD, so exif_tag_get_name_in_ifd won't work
 			 */
 			exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
-				  "Sub-IFD entry 0x%x at %u.", tag, o);
+				  "Sub-IFD entry 0x%x ('%s') at %u.", tag,
+				  exif_tag_get_name(tag), o);
 			switch (tag) {
 			case EXIF_TAG_EXIF_IFD_POINTER:
 				CHECK_REC (EXIF_IFD_EXIF);