1 files changed, 227 insertions, 0 deletions
diff --git a/src/video-support/AVIMetadataLoader.vala b/src/video-support/AVIMetadataLoader.vala
new file mode 100644
index 0000000..2b507e2
--- /dev/null
+++ b/src/video-support/AVIMetadataLoader.vala
@@ -0,0 +1,227 @@
+public class AVIMetadataLoader {
+
+    private File file = null;
+
+    // A numerical date string, i.e 2010:01:28 14:54:25
+    private const int NUMERICAL_DATE_LENGTH = 19;
+
+    // Marker for timestamp section in a Nikon nctg blob.
+    private const uint16 NIKON_NCTG_TIMESTAMP_MARKER = 0x13;
+
+    // Size limit to ensure we don't parse forever on a bad file.
+    private const int MAX_STRD_LENGTH = 100;
+
+    public AVIMetadataLoader(File file) {
+        this.file = file;
+    }
+
+    public MetadataDateTime? get_creation_date_time() {
+        return new MetadataDateTime(get_creation_date_time_for_avi());
+    }
+
+    public string? get_title() {
+        // Not supported.
+        return null;
+    }
+
+    // Checks if the given file is an AVI file.
+    public bool is_supported() {
+        AVIChunk chunk = new AVIChunk(file);
+        bool ret = false;
+        try {
+            chunk.open_file();
+            chunk.read_chunk();
+            // Look for the header and identifier.
+            if ("RIFF" == chunk.get_current_chunk_name() &&
+                "AVI " == chunk.read_name()) {
+                ret = true;
+            }
+        } catch (GLib.Error e) {
+            debug("Error while testing for AVI file: %s", e.message);
+        }
+
+        try {
+            chunk.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing AVI file: %s", e.message);
+        }
+        return ret;
+    }
+
+    // Parses a Nikon nctg tag.  Based losely on avi_read_nikon() in FFmpeg.
+    private string read_nikon_nctg_tag(AVIChunk chunk) throws GLib.Error {
+        bool found_date = false;
+        while (chunk.section_size_remaining() > sizeof(uint16)*2) {
+            uint16 tag = chunk.read_uint16();
+            uint16 size = chunk.read_uint16();
+            if (NIKON_NCTG_TIMESTAMP_MARKER == tag) {
+                found_date = true;
+                break;
+            }
+            chunk.skip(size);
+        }
+
+        if (found_date) {
+            // Read numerical date string, example: 2010:01:28 14:54:25
+            GLib.StringBuilder sb = new GLib.StringBuilder();
+            for (int i = 0; i < NUMERICAL_DATE_LENGTH; i++) {
+                sb.append_c((char) chunk.read_byte());
+            }
+            return sb.str;
+        }
+        return "";
+    }
+
+    // Parses a Fujifilm strd tag. Based on information from:
+    // http://www.eden-foundation.org/products/code/film_date_stamp/index.html
+    private string read_fuji_strd_tag(AVIChunk chunk) throws GLib.Error {
+        chunk.skip(98); // Ignore 98-byte binary blob.
+        chunk.skip(8); // Ignore the string "FUJIFILM"
+        // Read until we find four colons, then two more chars.
+        int colons = 0;
+        int post_colons = 0;
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        // End of date is two chars past the fourth colon.
+        while (colons <= 4 && post_colons < 2) {
+            char c = (char) chunk.read_byte();
+            if (4 == colons) {
+                post_colons++;
+            }
+            if (':' == c) {
+                colons++;
+            }
+            if (c.isprint()) {
+                sb.append_c(c);
+            }
+            if (sb.len > MAX_STRD_LENGTH) {
+                return ""; // Give up searching.
+            }
+        }
+
+        if (sb.str.length < NUMERICAL_DATE_LENGTH) {
+            return "";
+        }
+        // Date is now at the end of the string.
+        return sb.str.substring(sb.str.length - NUMERICAL_DATE_LENGTH);
+    }
+
+    // Recursively read file until the section is found.
+    private string? read_section(AVIChunk chunk) throws GLib.Error {
+        while (true) {
+            chunk.read_chunk();
+            string name = chunk.get_current_chunk_name();
+            if ("IDIT" == name) {
+                return chunk.section_to_string();
+            } else if ("nctg" == name) {
+                return read_nikon_nctg_tag(chunk);
+            } else if ("strd" == name) {
+                return read_fuji_strd_tag(chunk);
+            }
+
+            if ("LIST" == name) {
+                chunk.read_name(); // Read past list name.
+                string result = read_section(chunk.get_first_child_chunk());
+                if (null != result) {
+                    return result;
+                }
+            }
+
+            if (chunk.is_last_chunk()) {
+                break;
+            }
+            chunk.next_chunk();
+        }
+        return null;
+    }
+
+    // Parses a date from a string.
+    // Largely based on GStreamer's avi/gstavidemux.c
+    // and the information here:
+    // http://www.eden-foundation.org/products/code/film_date_stamp/index.html
+    private DateTime? parse_date(string sdate) {
+        if (sdate.length == 0) {
+            return null;
+        }
+
+        int year, month, day, hour, min, sec;
+        char weekday[4];
+        char monthstr[4];
+        DateTime parsed_date;
+
+        if (sdate[0].isdigit()) {
+            // Format is: 2005:08:17 11:42:43
+            // Format is: 2010/11/30/ 19:42
+            // Format is: 2010/11/30 19:42
+            string tmp = sdate.dup();
+            tmp.canon("0123456789 ", ' '); // strip everything but numbers and spaces
+            sec = 0;
+            int result = tmp.scanf("%d %d %d %d %d %d", out year, out month, out day, out hour, out min, out sec);
+            if(result < 5) {
+                return null;
+            }
+
+            parsed_date = new DateTime.utc(year, month, day, hour, min, sec);
+        } else {
+            // Format is: Mon Mar  3 09:44:56 2008
+            if(7 != sdate.scanf("%3s %3s %d %d:%d:%d %d", weekday, monthstr, out day, out hour,
+                  out min, out sec, out year)) {
+                return null; // Error
+            }
+            parsed_date = new DateTime.local(year, month_from_string((string)monthstr), day, hour, min, sec);
+        }
+
+        return parsed_date;
+    }
+
+    private DateMonth month_from_string(string s) {
+        switch (s.down()) {
+        case "jan":
+            return DateMonth.JANUARY;
+        case "feb":
+            return DateMonth.FEBRUARY;
+        case "mar":
+            return DateMonth.MARCH;
+        case "apr":
+            return DateMonth.APRIL;
+        case "may":
+            return DateMonth.MAY;
+        case "jun":
+            return DateMonth.JUNE;
+        case "jul":
+            return DateMonth.JULY;
+        case "aug":
+            return DateMonth.AUGUST;
+        case "sep":
+            return DateMonth.SEPTEMBER;
+        case "oct":
+            return DateMonth.OCTOBER;
+        case "nov":
+            return DateMonth.NOVEMBER;
+        case "dec":
+            return DateMonth.DECEMBER;
+        }
+        return DateMonth.BAD_MONTH;
+    }
+
+    private DateTime? get_creation_date_time_for_avi() {
+        AVIChunk chunk = new AVIChunk(file);
+        DateTime? timestamp = null;
+        try {
+            chunk.open_file();
+            chunk.nonsection_skip(12); // Advance past 12 byte header.
+            string sdate = read_section(chunk);
+            if (null != sdate) {
+                timestamp = parse_date(sdate.strip());
+            }
+        } catch (GLib.Error e) {
+            debug("Error while reading AVI file: %s", e.message);
+        }
+
+        try {
+            chunk.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing AVI file: %s", e.message);
+        }
+        return timestamp;
+    }
+}