3 files changed, 23 insertions, 3 deletions

diff --git a/exif.c b/exif.c
index a70b310..a0056e0 100644
--- a/exif.c
+++ b/exif.c
@@ -1091,6 +1091,15 @@ static void writeExifTagAndData(int tag,
         components = strlen((char*)value) + 1;                 // account for null terminator
         if (components & 1) ++components;               // no odd lengths
     }
+    if (format == FMT_UNDEFINED && components == -1) {
+        // check if this UNDEFINED format is actually ASCII (as it usually is)
+        // if so, we can calculate the size
+        if(memcmp((char*)value, ExifAsciiPrefix, sizeof(ExifAsciiPrefix)) == 0) {
+            components = sizeof(ExifAsciiPrefix) +
+                         strlen((char*)value + sizeof(ExifAsciiPrefix)) + 1;
+            if (components & 1) ++components;               // no odd lengths
+        }
+    }
     Put32u(Buffer+(*DirIndex) + 4, components);         // Components
     printf("# components: %ld", components);
     if (format == FMT_STRING) {
@@ -1104,6 +1113,18 @@ static void writeExifTagAndData(int tag,
             strncpy(Buffer+(*DataWriteIndex), (char*)value, components);
             (*DataWriteIndex) += components;
         }
+    } else if ((format == FMT_UNDEFINED) &&
+               (memcmp((char*)value, ExifAsciiPrefix, sizeof(ExifAsciiPrefix)) == 0)) {
+        // short strings can fit right in the long, otherwise have to
+        // go in the data area
+        if (components <= 4) {
+            memcpy(Buffer+(*DirIndex) + 8, (char*)value, components);
+        } else {
+            Put32u(Buffer+(*DirIndex) + 8, (*DataWriteIndex)-8);   // Pointer
+            printf("copying %s to %d", (char*)value + sizeof(ExifAsciiPrefix), (*DataWriteIndex));
+            memcpy(Buffer+(*DataWriteIndex), (char*)value, components);
+            (*DataWriteIndex) += components;
+        }
     } else if (!valueInString) {
         Put32u(Buffer+(*DirIndex) + 8, value);   // Value
     } else {
diff --git a/gpsinfo.c b/gpsinfo.c
index 7eef6ba..896ad28 100644
--- a/gpsinfo.c
+++ b/gpsinfo.c
@@ -47,14 +47,12 @@ static TagTable_t GpsTags[]= {
     { 0x18, "GPSDestBearing", FMT_SRATIONAL, 1},
     { 0x19, "GPSDestDistanceRef", FMT_STRING, 2},
     { 0x1A, "GPSDestDistance", FMT_SRATIONAL, 1},
-    { 0x1B, "GPSProcessingMethod", FMT_STRING, -1},
+    { 0x1B, "GPSProcessingMethod", FMT_UNDEFINED, -1},
     { 0x1C, "GPSAreaInformation", FMT_STRING, -1},
     { 0x1D, "GPSDateStamp", FMT_STRING, 11},
     { 0x1E, "GPSDifferential", FMT_SSHORT, 1},
 };
 
-static const char ExifAsciiPrefix[] = { 0x41, 0x53, 0x43, 0x49, 0x49, 0x0, 0x0, 0x0 };
-
 #define MAX_GPS_TAG  (sizeof(GpsTags) / sizeof(TagTable_t))
 #define EXIF_ASCII_PREFIX_LEN (sizeof(ExifAsciiPrefix))
 
diff --git a/jhead.h b/jhead.h
index 9d311e9..4347fe8 100644
--- a/jhead.h
+++ b/jhead.h
@@ -209,6 +209,7 @@ int IsGpsTag(const char* tag);
 int GpsTagToFormatType(unsigned short tag);
 int GpsTagNameToValue(const char* tagName);
 TagTable_t* GpsTagToTagTableEntry(unsigned short tag);
+static const char ExifAsciiPrefix[] = { 0x41, 0x53, 0x43, 0x49, 0x49, 0x0, 0x0, 0x0 };
 
 // iptc.c prototpyes
 void show_IPTC (unsigned char * CharBuf, unsigned int length);