android/apps: Add CanvasProof App;

platform_tools/android/apps/canvasproof/src/main/jni/JavaInputStream.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "JavaInputStream.h"
+
+JavaInputStream::JavaInputStream(
+        JNIEnv* env, jbyteArray javaBuffer, jobject inputStream)
+    : fEnv(env)
+    , fStartIndex(0)
+    , fEndIndex(0) {
+    SkASSERT(inputStream);
+    SkASSERT(javaBuffer);
+    fInputStream = inputStream;
+    fJavaBuffer = javaBuffer;
+    fInputStreamClass = env->FindClass("java/io/InputStream");
+    SkASSERT(fInputStreamClass);
+    fReadMethodID = env->GetMethodID(fInputStreamClass, "read", "([B)I");
+    SkASSERT(fReadMethodID);
+}
+
+bool JavaInputStream::isAtEnd() const { return fStartIndex == fEndIndex; }
+
+size_t JavaInputStream::read(void* voidBuffer, size_t size) {
+    size_t totalRead = 0;
+    char* buffer = static_cast<char*>(voidBuffer);  // may be NULL;
+    while (size) {
+        // make sure the cache has at least one byte or is done.
+        if (fStartIndex == fEndIndex) {
+            jint count =
+                fEnv->CallIntMethod(fInputStream, fReadMethodID, fJavaBuffer);
+            if (fEnv->ExceptionCheck()) {
+                fEnv->ExceptionDescribe();
+                fEnv->ExceptionClear();
+                SkDebugf("---- java.io.InputStream::read() threw an exception\n");
+                return 0;
+            }
+            fStartIndex = 0;
+            fEndIndex = count;
+            if (this->isAtEnd()) {
+                return totalRead;  // No more to read.
+            }
+        }
+        SkASSERT(fEndIndex > fStartIndex);
+        size_t length = SkTMin(SkToSizeT(fEndIndex - fStartIndex), size);
+        if (buffer && length) {
+            jbyte* bufferElements
+                = fEnv->GetByteArrayElements(fJavaBuffer, NULL);
+            memcpy(buffer, &bufferElements[fStartIndex], length);
+            buffer += length;
+            fEnv->ReleaseByteArrayElements(fJavaBuffer, bufferElements, 0);
+        }
+        totalRead += length;
+        size -= length;
+        fStartIndex += length;
+    }
+    return totalRead;
+}