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, 69 insertions, 0 deletions

diff --git a/jni_jpegstream/src/inputstream_wrapper.cpp b/jni_jpegstream/src/inputstream_wrapper.cpp
new file mode 100644
index 000000000..98721b066
--- /dev/null
+++ b/jni_jpegstream/src/inputstream_wrapper.cpp
@@ -0,0 +1,69 @@
+/*
+ * 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 "inputstream_wrapper.h"
+#include "error_codes.h"
+
+jmethodID InputStreamWrapper::sReadID = NULL;
+jmethodID InputStreamWrapper::sSkipID = NULL;
+
+int32_t InputStreamWrapper::read(int32_t length, int32_t offset) {
+    if (offset < 0 || length < 0 || (offset + length) > getBufferSize()) {
+        return J_ERROR_BAD_ARGS;
+    }
+    int32_t bytesRead = 0;
+    mEnv->ReleaseByteArrayElements(mByteArray, mBytes, JNI_COMMIT);
+    mBytes = NULL;
+    if (mEnv->ExceptionCheck()) {
+        return J_EXCEPTION;
+    }
+    bytesRead = static_cast<int32_t>(mEnv->CallIntMethod(mStream, sReadID,
+            mByteArray, offset, length));
+    if (mEnv->ExceptionCheck()) {
+        return J_EXCEPTION;
+    }
+    mBytes = mEnv->GetByteArrayElements(mByteArray, NULL);
+    if (mBytes == NULL || mEnv->ExceptionCheck()) {
+        return J_EXCEPTION;
+    }
+    if (bytesRead == END_OF_STREAM) {
+        return J_DONE;
+    }
+    return bytesRead;
+}
+
+int64_t InputStreamWrapper::skip(int64_t count) {
+    int64_t bytesSkipped = 0;
+    bytesSkipped = static_cast<int64_t>(mEnv->CallLongMethod(mStream, sSkipID,
+            static_cast<jlong>(count)));
+    if (mEnv->ExceptionCheck() || bytesSkipped < 0) {
+        return J_EXCEPTION;
+    }
+    return bytesSkipped;
+}
+
+// Acts like a read call that returns the End Of Image marker for a JPEG file.
+int32_t InputStreamWrapper::forceReadEOI() {
+    mBytes[0] = (jbyte) 0xFF;
+    mBytes[1] = (jbyte) 0xD9;
+    return 2;
+}
+
+void InputStreamWrapper::setReadSkipMethodIDs(jmethodID readID,
+        jmethodID skipID) {
+    sReadID = readID;
+    sSkipID = skipID;
+}