Imported Upstream version 0.22.0upstream/0.22.0

1 files changed, 98 insertions, 0 deletions

diff --git a/src/NaturalCollate.vala b/src/NaturalCollate.vala
new file mode 100644
index 0000000..4adb027
--- /dev/null
+++ b/src/NaturalCollate.vala
@@ -0,0 +1,98 @@
+/**
+ * NaturalCollate
+ * Simple helper class for natural sorting in Vala.
+ *
+ * (c) Tobia Tesan <tobia.tesan@gmail.com>, 2014
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Lesser GNU General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ */
+
+namespace NaturalCollate {
+
+private const unichar SUPERDIGIT = ':';
+private const unichar NUM_SENTINEL = 0x2; // glib uses these, so do we
+private const string  COLLATION_SENTINEL = "\x01\x01\x01";
+
+private static int read_number(owned string s, ref int byte_index) {
+    /*
+     * Given a string in the form [numerals]*[everythingelse]*
+     * returns the int value of the first block and increments index
+     * by its length as a side effect.
+     * Notice that "numerals" is not just 0-9 but everything else 
+     * Unicode considers a numeral (see: string::isdigit())
+     */
+    int number = 0;
+
+    while (s.length != 0 && s.get_char(0).isdigit()) {
+        number = number*10;
+        number += s.get_char(0).digit_value();
+        int second_char = s.index_of_nth_char(1);
+        s = s.substring(second_char);
+        byte_index += second_char;
+    }
+    return number;
+}
+
+public static int compare(string str1, string str2) {
+    return strcmp(collate_key(str1), collate_key(str2));
+}
+
+public static string collate_key(owned string str) {
+    /*
+     * Computes a collate key.
+     * Has roughly the same effect as g_utf8_collate_key_for_file, except that it doesn't
+     * handle the dot as a special char.
+     */
+    assert (str.validate());
+    string result = "";
+    bool eos = (str.length == 0);
+
+    while (!eos) {
+        assert(str.validate());
+        int position = 0;
+        while (!(str.get_char(position).to_string() in "0123456789")) {
+            // We only care about plain old 0123456789, aping what g_utf8_collate_key_for_filename does
+            position++;
+        }
+
+        // (0... position( is a bunch of non-numerical chars, so we compute and append the collate key...
+        result = result + (str.substring(0, position).collate_key());
+
+        // ...then throw them away
+        str = str.substring(position);
+
+        eos = (str.length == 0);
+        position = 0;
+
+        if (!eos) {
+            // We have some numbers to handle in front of us
+            int number = read_number(str, ref position);
+            str = str.substring(position);
+            int number_of_superdigits = number.to_string().length;
+            string to_append = "";
+            for (int i = 1; i < number_of_superdigits; i++) {
+                // We append n - 1 superdigits where n is the number of digits
+                to_append = to_append + SUPERDIGIT.to_string();
+            }
+            to_append = to_append + (number.to_string()); // We append the actual number
+            result = result +
+                     COLLATION_SENTINEL +
+                     NUM_SENTINEL.to_string() +
+                     to_append;
+        }
+        eos = (str.length == 0);
+    }
+
+    result = result + NUM_SENTINEL.to_string();
+    // No specific reason except that glib does it
+
+    return result;
+}
+}