Add support for datetime/timezone shift

Simple datetime shift, including EXIF data modification.

5 files changed, 215 insertions, 36 deletions

diff --git a/src/generators.c b/src/generators.c
index 9c65d8e..fe62b39 100644
--- a/src/generators.c
+++ b/src/generators.c
@@ -146,6 +146,22 @@ get_image_paths (TGallerySetup *setup,
 }
 
 
+static void
+metadata_apply_overrides (ExifData *exif_data,
+                          TGallerySetup *setup,
+                          TAlbum *items,
+                          TIndexItem *item)
+{
+  g_return_if_fail (exif_data != NULL);
+
+  g_free (exif_data->override_copyright);
+  exif_data->override_copyright = g_strdup (setup->add_copyright);
+  exif_data->timezone_shift = item->metadata_tz_shift;
+  if (exif_data->timezone_shift == 0)
+    exif_data->timezone_shift = items->metadata_tz_shift;
+}
+
+
 /*
  *     generate_image: generate needed image sizes
  */
@@ -167,6 +183,7 @@ generate_image (TGallerySetup *setup,
   int quality;
   GList *l;
   TImageSize *image_size;
+  ExifData *exif_data;
 
 
   res = ! query_update;
@@ -230,8 +247,12 @@ generate_image (TGallerySetup *setup,
         }
       }
     }
-    if (! is_thumbnail)
-      modify_exif (img_dst, setup->erase_exif_thumbnail, setup->add_copyright);
+    if (! is_thumbnail) {
+      exif_data = exif_data_new_empty ();
+      metadata_apply_overrides (exif_data, setup, items, item);
+      modify_exif (img_dst, exif_data, setup->erase_exif_thumbnail);
+      exif_data_free (exif_data);
+    }
 
     g_free (img_src);
     g_free (img_dst);
@@ -754,6 +775,7 @@ write_html_image (TGallerySetup *setup,
     if (exif == NULL)
       log_error ("write_html_image: error getting exif data from file \"%s\"\n", img_dst);
   }
+  metadata_apply_overrides (exif, setup, parent_items, item);
   /*  Test for basic EXIF keys presence  */
   if (exif != NULL && exif_has_key (exif, EXIF_APERTURE) &&
                       exif_has_key (exif, EXIF_FOCAL_LENGTH) &&
diff --git a/src/items.c b/src/items.c
index a0c2534..6ac7e56 100644
--- a/src/items.c
+++ b/src/items.c
@@ -30,6 +30,30 @@
 #include "atom-writer.h"
 
 
+
+static int
+parse_timezone_string (const gchar *str)
+{
+  int hour = 0;
+  int min = 0;
+  float f;
+  char *endptr = NULL;
+
+  /*  Expecting +-hh:mm format  */
+  if (sscanf (str, "%d:%d", &hour, &min) != 2) {
+    /*  Try simple float conversion instead  */
+    f = strtof (str, &endptr);
+    if (endptr == NULL || *endptr != '\0') {
+      log_error ("Invalid timezone string \"%s\", ignoring.\n", str);
+      return 0;
+    }
+    return (int)(f * 60);
+  }
+
+  return hour * 60 + min;
+}
+
+
 /*
  *   parse_album_xml: XML parser for gallery index.xml files
  */
@@ -92,6 +116,13 @@ parse_album_xml (const gchar *filename, TPathInfo *path_info)
   index->meta_description = xml_file_get_node_value (xml, "/gallery/general/meta/description/text()");
   index->meta_keywords = xml_file_get_node_value (xml, "/gallery/general/meta/keywords/text()");
 
+  s = xml_file_get_node_attribute (xml, "/gallery/general/metadata/timezone", "shift");
+  if (s != NULL) {
+    index->metadata_tz_shift = parse_timezone_string (s2);
+    g_free (s2);
+  }
+
+
   index->nofullsize = xml_file_get_node_present (xml, "/gallery/general/nofullsize");
   index->fullsize = xml_file_get_node_present (xml, "/gallery/general/fullsize");
 
@@ -219,6 +250,14 @@ parse_album_xml (const gchar *filename, TPathInfo *path_info)
       item->metadata_external_exif = xml_file_get_node_attribute (xml, s, "src");
       g_free (s);
 
+      s = g_strdup_printf ("/gallery/items/*[%d]/metadata/timezone", i + 1);
+      s2 = xml_file_get_node_attribute (xml, s, "shift");
+      g_free (s);
+      if (s2 != NULL) {
+        item->metadata_tz_shift = parse_timezone_string (s2);
+        g_free (s2);
+      }
+
       if (item->path || item->preview) {
         g_ptr_array_add (index->items, item);
       } else {
diff --git a/src/items.h b/src/items.h
index 15baeae..2b36927 100644
--- a/src/items.h
+++ b/src/items.h
@@ -64,6 +64,7 @@ typedef struct {
   gchar *auth_username;
   gchar *auth_passwd;
   TAuthType auth_type;
+  int metadata_tz_shift;  /*  minutes  */
 } TAlbum;
 
 typedef struct {
@@ -81,6 +82,7 @@ typedef struct {
   TIndexItemType type;
   gboolean hidden;
   gchar *metadata_external_exif;
+  int metadata_tz_shift;  /*  minutes  */
 } TIndexItem;
 
 typedef struct {
diff --git a/src/jpeg-utils.cpp b/src/jpeg-utils.cpp
index bee9562..df3c94e 100644
--- a/src/jpeg-utils.cpp
+++ b/src/jpeg-utils.cpp
@@ -30,11 +30,55 @@
 #include "gallery-utils.h"
 
 
-struct ExifData {
+struct ExifDataPrivate {
   Exiv2::Image::AutoPtr image;
 };
 
 
+static struct tm *
+parse_exif_date (const char *str)
+{
+  struct tm *tm;
+  char *res;
+
+  tm = (struct tm *) g_malloc0 (sizeof (struct tm));
+
+  res = strptime (str, "%Y:%m:%d %H:%M:%S", tm);
+  if (res == NULL || *res != '\0')
+    return NULL;
+
+  /*  FIXME: what was this used for?  */
+#if 0
+  tm->tm_year -= 1900;
+  tm->tm_mon--;
+#endif
+  mktime (tm);
+
+  return tm;
+}
+
+static void
+shift_time (struct tm *tm, int offset_min)
+{
+  time_t t;
+  struct tm *new_t;
+
+  if (offset_min != 0) {
+    /*  FIXME: converting between time formats could make some data lost, better to operate over struct tm directly  */
+    t = mktime (tm);
+    if (t == (time_t) -1) {
+      log_error ("Cannot shift time %p by %d minutes\n", tm, offset_min);
+      return;
+    }
+
+    t += offset_min * 60;
+
+    new_t = localtime (&t);
+    memcpy (tm, new_t, sizeof (struct tm));
+  }
+}
+
+
 /*
  *   EXIF and IPTC info retrieval, keeps the source file open until freed
  */
@@ -43,12 +87,12 @@ read_exif (const gchar *filename)
 {
   ExifData *data;
 
-  data = (ExifData*) g_malloc0 (sizeof (ExifData));
+  data = exif_data_new_empty ();
 
   try {
-    data->image = Exiv2::ImageFactory::open (filename);
-    g_assert (data->image.get() != 0);
-    data->image->readMetadata();
+    data->priv->image = Exiv2::ImageFactory::open (filename);
+    g_assert (data->priv->image.get() != 0);
+    data->priv->image->readMetadata();
   }
   catch (Exiv2::AnyError& e)
   {
@@ -60,11 +104,24 @@ read_exif (const gchar *filename)
   return data;
 }
 
+ExifData *
+exif_data_new_empty ()
+{
+  ExifData *data;
+
+  data = (ExifData*) g_malloc0 (sizeof (ExifData));
+  data->priv = (ExifDataPrivate*) g_malloc0 (sizeof (ExifDataPrivate));
+
+  return data;
+}
+
 void
 exif_data_free (ExifData *data)
 {
   if (data) {
-    /* FIXME: free data->image */
+    g_free (data->override_copyright);
+    /* FIXME: free data->priv->image */
+    g_free (data->priv);
     g_free (data);
   }
 }
@@ -103,18 +160,18 @@ get_exif_data (ExifData *exif, const gchar *key)
 
   try {
     if (g_strcmp0 (key, JPEG_COMMENT) == 0) {
-      return g_strdup (exif->image->comment().c_str());
+      return g_strdup (exif->priv->image->comment().c_str());
     }
 
     if (g_str_has_prefix (key, "Exif.")) {
-      Exiv2::ExifData &exifData = exif->image->exifData();
+      Exiv2::ExifData &exifData = exif->priv->image->exifData();
       if (! exifData.empty()) {
         return g_strdup (exifData[key].toString().c_str());
       }
     }
 
     if (g_str_has_prefix (key, "Iptc.")) {
-      Exiv2::IptcData &iptcData = exif->image->iptcData();
+      Exiv2::IptcData &iptcData = exif->priv->image->iptcData();
       if (! iptcData.empty()) {
         return g_strdup (iptcData[key].toString().c_str());
       }
@@ -136,7 +193,7 @@ get_exif_data_fixed (ExifData *exif, const gchar *key)
   try
   {
     if (g_str_has_prefix (key, "Exif.")) {
-      Exiv2::ExifData &exifData = exif->image->exifData();
+      Exiv2::ExifData &exifData = exif->priv->image->exifData();
       if (exifData.empty())
         return NULL;
 
@@ -153,24 +210,29 @@ get_exif_data_fixed (ExifData *exif, const gchar *key)
         } catch (...) { }
         if (! val || strlen (val) == 0)
           try {
+            val = exifData["Exif.Photo.DateTimeDigitized"].toString().c_str();
+          } catch (...) { }
+        if (! val || strlen (val) == 0)
+          try {
+            /*  usually a modification date  */
             val = exifData["Exif.Image.DateTime"].toString().c_str();
           } catch (...) { }
 
         if (val && strlen (val) > 0) {
-          struct tm tt;
+          struct tm *tt;
           char conv[1024];
 
           memset (&conv, 0, sizeof (conv));
-          memset (&tt, 0, sizeof (struct tm));
-
-          if (sscanf (val, "%d:%d:%d %d:%d:%d", &tt.tm_year, &tt.tm_mon, &tt.tm_mday, &tt.tm_hour, &tt.tm_min, &tt.tm_sec) == 6)
-            {
-              tt.tm_year -= 1900;
-              tt.tm_mon--;
-              mktime (&tt);
-              if (strftime (&conv[0], sizeof (conv), "%c", &tt))
-                  return g_strdup (&conv[0]);
+
+          tt = parse_exif_date (val);
+          if (tt) {
+            shift_time (tt, exif->timezone_shift);
+            if (strftime (&conv[0], sizeof (conv), "%c", tt)) {
+              g_free (tt);
+              return g_strdup (&conv[0]);
             }
+            g_free (tt);
+          }
         }
       }
 
@@ -214,7 +276,7 @@ get_exif_data_fixed (ExifData *exif, const gchar *key)
     }
 
     if (g_str_has_prefix (key, "Iptc.")) {
-      Exiv2::IptcData &iptcData = exif->image->iptcData();
+      Exiv2::IptcData &iptcData = exif->priv->image->iptcData();
       if (iptcData.empty())
         return NULL;
     }
@@ -239,16 +301,16 @@ exif_has_key (ExifData *exif, const gchar *key)
 
   try {
     if (g_strcmp0 (key, JPEG_COMMENT) == 0) {
-      return (! exif->image->comment().empty());
+      return (! exif->priv->image->comment().empty());
     }
 
     if (g_str_has_prefix (key, "Exif.")) {
-      Exiv2::ExifData &exifData = exif->image->exifData();
+      Exiv2::ExifData &exifData = exif->priv->image->exifData();
       return !exifData.empty() && exifData[key].count() > 0;
     }
 
     if (g_str_has_prefix (key, "Iptc.")) {
-      Exiv2::IptcData &iptcData = exif->image->iptcData();
+      Exiv2::IptcData &iptcData = exif->priv->image->iptcData();
       return !iptcData.empty() && iptcData[key].count() > 0;
     }
 
@@ -450,17 +512,50 @@ calculate_sizes (const unsigned long max_width, const unsigned long max_height,
   }
 }
 
+static gboolean
+shift_exif_time (Exiv2::ExifData& exifData, const char *key, int amount)
+{
+  const char *s;
+  gboolean res;
+
+  res = FALSE;
+  try {
+    if (exifData[key].count() > 0) {
+      s = exifData[key].toString().c_str();
+
+      if (s && strlen (s) > 0) {
+        struct tm *tt;
+        char conv[1024];
+
+        memset (&conv, 0, sizeof (conv));
+
+        tt = parse_exif_date (s);
+        if (tt) {
+          shift_time (tt, amount);
+          if (strftime (&conv[0], sizeof (conv), "%Y:%m:%d %H:%M:%S", tt)) {
+            exifData[key] = (const char *) &conv[0];
+            res = TRUE;
+          }
+          g_free (tt);
+        }
+      }
+    }
+  } catch (...) {  }
+
+  return res;
+}
 
 /*
  *   modify_exif: - strip thumbnail stored in EXIF table
- *                - add copyright to Exif::Image::Copyright and Iptc::Application2::Copyright
+ *                - write down overriden keys
  */
 void
-modify_exif (const gchar *filename, gboolean strip_thumbnail, const gchar *add_copyright)
+modify_exif (const gchar *filename, ExifData *exif, gboolean strip_thumbnail)
 {
   gboolean modified;
+  gboolean res;
 
-  if (! strip_thumbnail && add_copyright == NULL)
+  if (! strip_thumbnail && exif == NULL)
     return;
 
   modified = FALSE;
@@ -470,10 +565,23 @@ modify_exif (const gchar *filename, gboolean strip_thumbnail, const gchar *add_c
 
     image->readMetadata();
     Exiv2::ExifData &exifData = image->exifData();
-    if (add_copyright) {
-      exifData["Exif.Image.Copyright"] = add_copyright;
-      image->iptcData()["Iptc.Application2.Copyright"] = add_copyright;
-      modified = TRUE;
+
+    if (exif) {
+      if (exif->override_copyright) {
+        exifData["Exif.Image.Copyright"] = exif->override_copyright;
+        image->iptcData()["Iptc.Application2.Copyright"] = exif->override_copyright;
+        modified = TRUE;
+      }
+
+      if (exif->timezone_shift != 0 && !exifData.empty()) {
+        /*  need original data to calculate the shift from  */
+        res = shift_exif_time (exifData, "Exif.Photo.DateTimeOriginal", exif->timezone_shift);
+        res = shift_exif_time (exifData, "Exif.Photo.DateTimeDigitized", exif->timezone_shift) || res;
+        if (! res)
+          /*  usually a modification date, shift as a last option  */
+          shift_exif_time (exifData, "Exif.Image.DateTime", exif->timezone_shift);
+        modified = TRUE;
+      }
     }
 
     if (strip_thumbnail && ! exifData.empty())  {
diff --git a/src/jpeg-utils.h b/src/jpeg-utils.h
index 86602a2..89a2cd4 100644
--- a/src/jpeg-utils.h
+++ b/src/jpeg-utils.h
@@ -45,13 +45,21 @@ G_BEGIN_DECLS
 #define JPEG_COMMENT            "Jpeg.Comment"
 
 
-typedef struct ExifData ExifData;
+typedef struct ExifDataPrivate ExifDataPrivate;
+
+typedef struct {
+  ExifDataPrivate *priv;
+
+  gchar *override_copyright;
+  int timezone_shift;
+} ExifData;
 
 
 /*
  *   EXIF and IPTC info retrieval, keeps the source file open until freed
  */
 ExifData * read_exif (const gchar *filename);
+ExifData * exif_data_new_empty ();
 void exif_data_free (ExifData *data);
 
 /*
@@ -95,9 +103,9 @@ void calculate_sizes (const unsigned long max_width, const unsigned long max_hei
 
 /*
  *   modify_exif: - strip thumbnail stored in EXIF table
- *                - add copyright to Exif::Image::Copyright and Iptc::Application2::Copyright
+ *                - write down overriden keys
  */
-void modify_exif (const gchar *filename, gboolean strip_thumbnail, const gchar *add_copyright);
+void modify_exif (const gchar *filename, ExifData *exif, gboolean strip_thumbnail);
 
 
 G_END_DECLS