Added jpeg streaming classes.

- Provides streaming operations for decompressing/compressing
  JPEG files.
- Allows pixel operations to be performed on large JPEG images
  without holding the entire bitmap in memory.

Change-Id: I597ddf282b59d2ba6d6bca4722208121e3728f94

1 files changed, 97 insertions, 0 deletions

diff --git a/jni_jpegstream/src/stream_wrapper.cpp b/jni_jpegstream/src/stream_wrapper.cpp
new file mode 100644
index 000000000..049d84f67
--- /dev/null
+++ b/jni_jpegstream/src/stream_wrapper.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "stream_wrapper.h"
+
+const int32_t StreamWrapper::END_OF_STREAM = -1;
+const int32_t StreamWrapper::DEFAULT_BUFFER_SIZE = 1 << 16;  // 64Kb
+
+StreamWrapper::StreamWrapper() : mEnv(NULL),
+                                 mStream(NULL),
+                                 mByteArray(NULL),
+                                 mBytes(NULL),
+                                 mByteArrayLen(0) {}
+
+StreamWrapper::~StreamWrapper() {
+    cleanup();
+}
+
+void StreamWrapper::updateEnv(JNIEnv *env) {
+    if (env == NULL) {
+        LOGE("Cannot update StreamWrapper with a null JNIEnv pointer!");
+        return;
+    }
+    mEnv = env;
+}
+
+bool StreamWrapper::init(JNIEnv *env, jobject stream) {
+    if (mEnv != NULL) {
+        LOGW("StreamWrapper already initialized!");
+        return false;
+    }
+    mEnv = env;
+    mStream = env->NewGlobalRef(stream);
+    if (mStream == NULL || env->ExceptionCheck()) {
+        cleanup();
+        return false;
+    }
+    mByteArrayLen = DEFAULT_BUFFER_SIZE;
+    jbyteArray tmp = env->NewByteArray(getBufferSize());
+    if (tmp == NULL || env->ExceptionCheck()){
+        cleanup();
+        return false;
+    }
+    mByteArray = reinterpret_cast<jbyteArray>(env->NewGlobalRef(tmp));
+    if (mByteArray == NULL || env->ExceptionCheck()){
+        cleanup();
+        return false;
+    }
+    mBytes = env->GetByteArrayElements(mByteArray, NULL);
+    if (mBytes == NULL || env->ExceptionCheck()){
+        cleanup();
+        return false;
+    }
+    return true;
+}
+
+void StreamWrapper::cleanup() {
+    if (mEnv != NULL) {
+        if (mStream != NULL) {
+            mEnv->DeleteGlobalRef(mStream);
+            mStream = NULL;
+        }
+        if (mByteArray != NULL) {
+            if (mBytes != NULL) {
+                mEnv->ReleaseByteArrayElements(mByteArray, mBytes, JNI_ABORT);
+                mBytes = NULL;
+            }
+            mEnv->DeleteGlobalRef(mByteArray);
+            mByteArray = NULL;
+        } else {
+            mBytes = NULL;
+        }
+        mByteArrayLen = 0;
+        mEnv = NULL;
+    }
+}
+
+int32_t StreamWrapper::getBufferSize() {
+    return mByteArrayLen;
+}
+
+jbyte* StreamWrapper::getBufferPtr() {
+    return mBytes;
+}