Merge "Support streaming of compressed assets > 1 megabyte" into gingerbread

2 files changed, 84 insertions, 9 deletions

diff --git a/include/utils/Asset.h b/include/utils/Asset.h
index 5908bcc..2a09095 100644
--- a/include/utils/Asset.h
+++ b/include/utils/Asset.h
@@ -61,15 +61,6 @@ public:
         ACCESS_BUFFER,
     } AccessMode;
 
-    enum {
-        /* data larger than this does not get uncompressed into a buffer */
-#ifdef HAVE_ANDROID_OS
-        UNCOMPRESS_DATA_MAX = 1 * 1024 * 1024
-#else
-        UNCOMPRESS_DATA_MAX = 2 * 1024 * 1024
-#endif
-    };
-
     /*
      * Read data from the current offset.  Returns the actual number of
      * bytes read, 0 on EOF, or -1 on error.
@@ -317,6 +308,8 @@ private:
     FileMap*    mMap;           // for memory-mapped input
     int         mFd;            // for file input
 
+    class StreamingZipInflater* mZipInflater;  // for streaming large compressed assets
+
     unsigned char*  mBuf;       // for getBuffer()
 };
 
diff --git a/include/utils/StreamingZipInflater.h b/include/utils/StreamingZipInflater.h
new file mode 100644
index 0000000..16867d8
--- /dev/null
+++ b/include/utils/StreamingZipInflater.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2010 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 __LIBS_STREAMINGZIPINFLATER_H
+#define __LIBS_STREAMINGZIPINFLATER_H
+
+#include <unistd.h>
+#include <inttypes.h>
+#include <zlib.h>
+
+namespace android {
+
+class StreamingZipInflater {
+public:
+    static const size_t INPUT_CHUNK_SIZE = 64 * 1024;
+    static const size_t OUTPUT_CHUNK_SIZE = 64 * 1024;
+
+    // Flavor that pages in the compressed data from a fd
+    StreamingZipInflater(int fd, off_t compDataStart, size_t uncompSize, size_t compSize);
+
+    // Flavor that gets the compressed data from an in-memory buffer
+    StreamingZipInflater(class FileMap* dataMap, size_t uncompSize);
+
+    ~StreamingZipInflater();
+
+    // read 'count' bytes of uncompressed data from the current position.  outBuf may
+    // be NULL, in which case the data is consumed and discarded.
+    ssize_t read(void* outBuf, size_t count);
+
+    // seeking backwards requires uncompressing fom the beginning, so is very
+    // expensive.  seeking forwards only requires uncompressing from the current
+    // position to the destination.
+    off_t seekAbsolute(off_t absoluteInputPosition);
+
+private:
+    void initInflateState();
+    int readNextChunk();
+
+    // where to find the uncompressed data
+    int mFd;
+    off_t mInFileStart;         // where the compressed data lives in the file
+    class FileMap* mDataMap;
+
+    z_stream mInflateState;
+    bool mStreamNeedsInit;
+
+    // output invariants for this asset
+    uint8_t* mOutBuf;           // output buf for decompressed bytes
+    size_t mOutBufSize;         // allocated size of mOutBuf
+    size_t mOutTotalSize;       // total uncompressed size of the blob
+
+    // current output state bookkeeping
+    off_t mOutCurPosition;      // current position in total offset
+    size_t mOutLastDecoded;     // last decoded byte + 1 in mOutbuf
+    size_t mOutDeliverable;     // next undelivered byte of decoded output in mOutBuf
+
+    // input invariants
+    uint8_t* mInBuf;
+    size_t mInBufSize;          // allocated size of mInBuf;
+    size_t mInTotalSize;        // total size of compressed data for this blob
+
+    // input state bookkeeping
+    size_t mInNextChunkOffset;  // offset from start of blob at which the next input chunk lies
+    // the z_stream contains state about input block consumption
+};
+
+}
+
+#endif