Sort non zero-padded numerical filename parts correctly.

2 files changed, 49 insertions, 0 deletions

diff --git a/utils/utils.c b/utils/utils.c
index 7155ef78d..ac9f5af7a 100644
--- a/utils/utils.c
+++ b/utils/utils.c
@@ -340,6 +340,41 @@ char *strndup(const char *s, size_t n)
 #endif
 
 
+/* Exported interface, documented in utils.c */
+int dir_sort_alpha(const struct dirent **d1, const struct dirent **d2)
+{
+	const char *s1 = (*d1)->d_name;
+	const char *s2 = (*d2)->d_name;
+
+	while (*s1 != '\0' && *s2 != '\0') {
+		if ((*s1 >= '0' && *s1 <= '9') &&
+				(*s2 >= '0' && *s2 <= '9')) {
+			int n1 = 0,  n2 = 0;
+			while (*s1 >= '0' && *s1 <= '9') {
+				n1 = n1 * 10 + (*s1) - '0';
+				s1++;
+			}
+			while (*s2 >= '0' && *s2 <= '9') {
+				n2 = n2 * 10 + (*s2) - '0';
+				s2++;
+			}
+			if (n1 != n2) {
+				return n1 - n2;
+			}
+			if (*s1 == '\0' || *s2 == '\0')
+				break;
+		}
+		if (tolower(*s1) != tolower(*s2))
+			break;
+
+		s1++;
+		s2++;
+	}
+
+	return tolower(*s1) - tolower(*s2);
+}
+
+
 #ifndef HAVE_SCANDIR
 int alphasort(const struct dirent **d1, const struct dirent **d2)
 {
diff --git a/utils/utils.h b/utils/utils.h
index 8172d2d26..a1ff683d3 100644
--- a/utils/utils.h
+++ b/utils/utils.h
@@ -29,6 +29,8 @@
 #include <regex.h>
 #include <assert.h>
 
+struct dirent;
+
 #ifndef NOF_ELEMENTS
 #define NOF_ELEMENTS(array) (sizeof(array)/sizeof(*(array)))
 #endif
@@ -157,6 +159,18 @@ char *human_friendly_bytesize(unsigned long bytesize);
 const char *rfc1123_date(time_t t);
 unsigned int wallclock(void);
 
+
+/**
+ * Comparison function for sorting directories.
+ *
+ * Correctly orders non zero-padded numerical parts.
+ * ie. produces "file1, file2, file10" rather than "file1, file10, file2".
+ *
+ * d1	first directory entry
+ * d2	second directory entry
+ */
+int dir_sort_alpha(const struct dirent **d1, const struct dirent **d2);
+
 /**
  * Return a hex digit for the given numerical value.
  *