Merge pull request #62 from r-ralph/fix-misc

Fix internal API usage and update comment

Author: r-ralph

apng-drawable/src/main/cpp/apng-drawbale/ApngDecoderJni.cpp

@@ -41,7 +41,7 @@ static jfieldID gResult_repeatCountFieldID;
 static jfieldID gResult_frameDurationsFieldID;
 static jfieldID gResult_allFrameByteCountFieldID;
 
-bool copyFrameDurations(JNIEnv *env,
+void copyFrameDurations(JNIEnv *env,
                         const std::shared_ptr<ApngImage> &image,
                         jintArray &frame_durations_ptr);
 
@@ -281,22 +281,19 @@ Java_com_linecorp_apng_decoder_ApngDecoderJni_copy(
 #pragma clang diagnostic pop
 }
 
-bool copyFrameDurations(JNIEnv *env,
+void copyFrameDurations(JNIEnv *env,
                         const std::shared_ptr<ApngImage> &image,
                         jintArray &frame_durations_ptr) {
   uint32_t frame_count = image->getFrameCount();
   jint *frame_durations_array = env->GetIntArrayElements(frame_durations_ptr, nullptr);
-  bool isSuccess = true;
   for (uint32_t i = 0; i < frame_count; ++i) {
     std::shared_ptr<ApngFrame> frame = image->getFrame(i);
     if (!frame) {
-      isSuccess = false;
       break;
     }
     frame_durations_array[i] = frame->getDuration();
   }
   env->ReleaseIntArrayElements(frame_durations_ptr, frame_durations_array, 0);
-  return isSuccess;
 }
 
 }

apng-drawable/src/main/cpp/apng-drawbale/ApngImage.cpp

@@ -43,13 +43,5 @@ void ApngImage::setFrame(const uint32_t index, std::unique_ptr<ApngFrame> frame)
   }
   mFrames[index] = std::move(frame);
 }
-
-uint32_t ApngImage::getTotalDuration() const {
-  uint32_t totalDuration = 0;
-  for (uint32_t i = 0; i < mFrameCount; i++) {
-    totalDuration += mFrames[i]->getDuration();
-  }
-  return totalDuration;
-}
 }
 

apng-drawable/src/main/cpp/apng-drawbale/ApngImage.h

@@ -29,7 +29,6 @@ class ApngImage {
   ApngImage() = delete;
   uint32_t getWidth() const { return mWidth; }
   uint32_t getHeight() const { return mHeight; }
-  uint32_t getTotalDuration() const;
   uint32_t getRepeatCount() const { return mLoopCount; }
   uint32_t getFrameCount() const { return mFrameCount; }
   uint32_t getFrameByteCount() const { return sizeof(uint32_t) * mWidth * mHeight; }

apng-drawable/src/main/kotlin/com/linecorp/apng/ApngDrawable.kt

@@ -93,10 +93,8 @@ class ApngDrawable @VisibleForTesting internal constructor(
     @IntRange(from = LOOP_INTRINSIC.toLong(), to = Int.MAX_VALUE.toLong())
     var loopCount: Int = apngState.apng.loopCount
         set(value) {
-            if (value < LOOP_INTRINSIC) {
-                throw IllegalArgumentException(
-                    "`loopCount` must be a signed value or special values. (value = $value)"
-                )
+            require(value >= LOOP_INTRINSIC) {
+                "`loopCount` must be a signed value or special values. (value = $value)"
             }
             field = if (value == LOOP_INTRINSIC) apngState.apng.loopCount else value
         }
@@ -115,22 +113,14 @@ class ApngDrawable @VisibleForTesting internal constructor(
             if (currentRepeatCountInternal > loopCount) loopCount else currentRepeatCountInternal
 
     /**
-     * [currentFrameIndex] is the index to indicate which frame should show at that time.
-     * [currentFrameIndex] is calculated with APNG meta data and elapsed time after animation
-     * started.
-     * [durationMillis] is the duration to animate one loop of APNG animation. [frameCount]
-     * is number of APNG frames. For example, if one loop duration is 1000ms, image count is 10 and
-     * elapsed time is 2100ms, the frame index should be 1 of 3rd loop.
-     * If this image isn't infinite looping image and [animationElapsedTimeMillis] is larger than
-     * total duration of this image's animation, returns always last frame index.
+     * The corresponding frame index with the elapsed time of the animation. This value indicates
+     * the last frame after the animation finished.
      */
     val currentFrameIndex: Int
-        get() = if (loopCount != LOOP_FOREVER && exceedsRepeatCountLimitation()) {
-            frameCount - 1
-        } else {
-            val durationInSingleLoop = animationElapsedTimeMillis % durationMillis
-            val index = frameStartTimes.indexOfFirst { durationInSingleLoop < it } - 1
-            if (index < 0) frameCount - 1 else index
+        get() {
+            var progressMillisInCurrentLoop = animationElapsedTimeMillis % durationMillis
+            progressMillisInCurrentLoop += if (exceedsRepeatCountLimitation()) durationMillis else 0
+            return calculateCurrentFrameIndex(0, frameCount - 1, progressMillisInCurrentLoop)
         }
 
     private val currentRepeatCountInternal: Int
@@ -345,6 +335,35 @@ class ApngDrawable @VisibleForTesting internal constructor(
         bounds.set(0, 0, scaledWidth, scaledHeight)
     }
 
+    private tailrec fun calculateCurrentFrameIndex(
+        lowerBoundIndex: Int,
+        upperBoundIndex: Int,
+        progressMillisInCurrentLoop: Long
+    ): Int {
+        val middleIndex = (lowerBoundIndex + upperBoundIndex) / 2
+        return when {
+            // Continue searching in the upper half
+            frameStartTimes.size > middleIndex + 1 &&
+                    progressMillisInCurrentLoop >= frameStartTimes[middleIndex + 1] ->
+                calculateCurrentFrameIndex(
+                    middleIndex + 1,
+                    upperBoundIndex,
+                    progressMillisInCurrentLoop
+                )
+
+            // Continue searching in the lower half
+            lowerBoundIndex != upperBoundIndex &&
+                    progressMillisInCurrentLoop < frameStartTimes[middleIndex] ->
+                calculateCurrentFrameIndex(
+                    lowerBoundIndex,
+                    middleIndex,
+                    progressMillisInCurrentLoop
+                )
+
+            else -> middleIndex
+        }
+    }
+
     internal class ApngState(
         val apng: Apng,
         /**