From 0a7720cce4068a08a5b9a06cefa537de846fa099 Mon Sep 17 00:00:00 2001
From: Ruben Brunk <rubenbrunk@google.com>
Date: Fri, 28 Jun 2013 20:02:54 -0700
Subject: 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
---
 jni_jpegstream/src/jpeg_writer.h | 83 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 jni_jpegstream/src/jpeg_writer.h

(limited to 'jni_jpegstream/src/jpeg_writer.h')

diff --git a/jni_jpegstream/src/jpeg_writer.h b/jni_jpegstream/src/jpeg_writer.h
new file mode 100644
index 000000000..bd9a42d32
--- /dev/null
+++ b/jni_jpegstream/src/jpeg_writer.h
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ */
+#ifndef JPEG_WRITER_H_
+#define JPEG_WRITER_H_
+
+#include "jerr_hook.h"
+#include "jni_defines.h"
+#include "jpeg_config.h"
+
+#include <stdint.h>
+
+/**
+ * JpegWriter wraps libjpeg's compression functionality and a
+ * java OutputStream object.  Write calls result in input data
+ * being compressed and written to the OuputStream.
+ */
+class JpegWriter {
+public:
+    JpegWriter();
+    ~JpegWriter();
+
+    /**
+     * Call setup with a valid OutputStream reference, bitmap height and
+     * width, pixel format, and compression quality in range (0, 100].
+     *
+     * Returns J_SUCCESS on success or a negative error code.
+     */
+    int32_t setup(JNIEnv *env, jobject out, int32_t width, int32_t height,
+            Jpeg_Config::Format format, int32_t quality);
+
+    /**
+     * Compresses bytes from the input buffer.
+     *
+     * ***This method will result in bytes being written to the OutputStream***
+     *
+     * Returns J_SUCCESS on success or a negative error code.
+     */
+    int32_t write(int8_t* bytes, int32_t length);
+
+    /**
+     * Updates the environment pointer.  Call this before write or reset
+     * in any jni function call.
+     */
+    void updateEnv(JNIEnv *env);
+
+    /**
+     * Frees any java global references held by the JpegWriter, destroys
+     * the compress structure, and frees allocations in libjpeg's pools.
+     */
+    int32_t reset();
+
+    static const int32_t DEFAULT_X_DENSITY;
+    static const int32_t DEFAULT_Y_DENSITY;
+    static const int32_t DEFAULT_DENSITY_UNIT;
+private:
+    void formatPixels(uint8_t* buf, int32_t len);
+    struct jpeg_compress_struct mInfo;
+    ErrManager mErrorManager;
+
+    JSAMPLE* mScanlineBuf;
+    JSAMPLE* mScanlineIter;
+    int32_t mScanlineBuflen;
+    int32_t mScanlineBytesRemaining;
+
+    Jpeg_Config::Format mFormat;
+    bool mFinished;
+    bool mSetup;
+};
+
+#endif // JPEG_WRITER_H_
-- 
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