Change focal length string to rational.

bug:2375989

3 files changed, 24 insertions, 8 deletions

diff --git a/exif.c b/exif.c
index 1efe3d9..f7a6365 100644
--- a/exif.c
+++ b/exif.c
@@ -717,7 +717,8 @@ static void ProcessExifDir(unsigned char * DirStart, unsigned char * OffsetBase,
             case TAG_FOCALLENGTH:
                 // Nice digital cameras actually save the focal length as a function
                 // of how farthey are zoomed in.
-                ImageInfo.FocalLength = (float)ConvertAnyFormat(ValuePtr, Format);
+                ImageInfo.FocalLength.num = Get32u(ValuePtr);
+                ImageInfo.FocalLength.denom = Get32u(4+(char *)ValuePtr);
                 break;
 
             case TAG_SUBJECT_DISTANCE:
@@ -1047,10 +1048,13 @@ void process_EXIF (unsigned char * ExifSection, unsigned int length)
         // that Jhad can do about it - its a camera problem.
         ImageInfo.CCDWidth = (float)(ExifImageWidth * FocalplaneUnits / FocalplaneXRes);
 
-        if (ImageInfo.FocalLength && ImageInfo.FocalLength35mmEquiv == 0){
+        if (ImageInfo.FocalLength.num != 0 && ImageInfo.FocalLength.denom != 0
+            && ImageInfo.FocalLength35mmEquiv == 0){
             // Compute 35 mm equivalent focal length based on sensor geometry if we haven't
             // already got it explicitly from a tag.
-            ImageInfo.FocalLength35mmEquiv = (int)(ImageInfo.FocalLength/ImageInfo.CCDWidth*36 + 0.5);
+            ImageInfo.FocalLength35mmEquiv = (int)(
+                (double)ImageInfo.FocalLength.num / ImageInfo.FocalLength.denom
+                / ImageInfo.CCDWidth * 36 + 0.5);
         }
     }
 }
@@ -1559,8 +1563,8 @@ void ShowImageInfo(int ShowFileInfo)
     }
 
 
-    if (ImageInfo.FocalLength){
-        printf("Focal length : %4.1fmm",(double)ImageInfo.FocalLength);
+    if (ImageInfo.FocalLength.num != 0 && ImageInfo.FocalLength.denom != 0) {
+        printf("Focal length : %4.1fmm",(double)ImageInfo.FocalLength.num / ImageInfo.FocalLength.denom);
         if (ImageInfo.FocalLength35mmEquiv){
             printf("  (35mm equivalent: %dmm)", ImageInfo.FocalLength35mmEquiv);
         }
diff --git a/jhead.h b/jhead.h
index 1725f74..2f640dd 100644
--- a/jhead.h
+++ b/jhead.h
@@ -59,6 +59,11 @@ extern int DumpExifMap;
 
 #define MAX_DATE_COPIES 10
 
+typedef struct {
+    uint32_t num;
+    uint32_t denom;
+} rat_t;
+
 //--------------------------------------------------------------------------
 // This structure stores Exif header image elements in a simple manner
 // Used to store camera data as extracted from the various ways that it can be
@@ -75,7 +80,7 @@ typedef struct {
     int   IsColor;
     int   Process;
     int   FlashUsed;
-    float FocalLength;
+    rat_t FocalLength;
     float ExposureTime;
     float ApertureFNumber;
     float Distance;
diff --git a/main.c b/main.c
index 682e892..6ea1219 100644
--- a/main.c
+++ b/main.c
@@ -517,6 +517,13 @@ static int addKeyValueDouble(char** buf, int bufLen, const char* key, double val
     return addKeyValueString(buf, bufLen, key, valueStr);
 }
 
+// Returns new buffer length. Rational value will be appended as "numerator/denominator".
+static int addKeyValueRational(char** buf, int bufLen, const char* key, rat_t value) {
+    char valueStr[25];
+    snprintf(valueStr, sizeof(valueStr), "%u/%u", value.num, value.denom);
+    return addKeyValueString(buf, bufLen, key, valueStr);
+}
+
 static jstring getAttributes(JNIEnv *env, jobject jobj, jstring jfilename)
 {
 #ifdef SUPERDEBUG
@@ -571,8 +578,8 @@ static jstring getAttributes(JNIEnv *env, jobject jobj, jstring jfilename)
     bufLen = addKeyValueInt(&buf, bufLen, "Flash", ImageInfo.FlashUsed);
     if (bufLen == 0) return NULL;
 
-    if (ImageInfo.FocalLength){
-        bufLen = addKeyValueInt(&buf, bufLen, "FocalLength", ImageInfo.FocalLength);
+    if (ImageInfo.FocalLength.num != 0 && ImageInfo.FocalLength.denom != 0) {
+        bufLen = addKeyValueRational(&buf, bufLen, "FocalLength", ImageInfo.FocalLength);
         if (bufLen == 0) return NULL;
     }