libs/androidfw/StreamingZipInflater.cpp - platform/frameworks/base - Gitiles

 /*
  * 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.
  */

 //#define LOG_NDEBUG 0
 #define LOG_TAG "szipinf"
 #include <utils/Log.h>

 #include <androidfw/StreamingZipInflater.h>
 #include <utils/FileMap.h>
 #include <string.h>
 #include <stddef.h>
 #include <assert.h>
 #include <unistd.h>
 #include <errno.h>

 /*
  * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
  * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
  * not already defined, then define it here.
  */
 #ifndef TEMP_FAILURE_RETRY
 /* Used to retry syscalls that can return EINTR. */
 #define TEMP_FAILURE_RETRY(exp) ({         \
     typeof (exp) _rc;                      \
     do {                                   \
         _rc = (exp);                       \
     } while (_rc == -1 && errno == EINTR); \
     _rc; })
 #endif

 static const bool kIsDebug = false;

 static inline size_t min_of(size_t a, size_t b) { return (a < b) ? a : b; }

 using namespace android;

 /*
  * Streaming access to compressed asset data in an open fd
  */
 StreamingZipInflater::StreamingZipInflater(int fd, off64_t compDataStart,
         size_t uncompSize, size_t compSize) {
     mFd = fd;
     mDataMap = NULL;
     mInFileStart = compDataStart;
     mOutTotalSize = uncompSize;
     mInTotalSize = compSize;

     mInBufSize = StreamingZipInflater::INPUT_CHUNK_SIZE;
     mInBuf = new uint8_t[mInBufSize];

     mOutBufSize = StreamingZipInflater::OUTPUT_CHUNK_SIZE;
     mOutBuf = new uint8_t[mOutBufSize];

     initInflateState();
 }

 /*
  * Streaming access to compressed data held in an mmapped region of memory
  */
 StreamingZipInflater::StreamingZipInflater(FileMap* dataMap, size_t uncompSize) {
     mFd = -1;
     mDataMap = dataMap;
     mOutTotalSize = uncompSize;
     mInTotalSize = dataMap->getDataLength();

     mInBuf = (uint8_t*) dataMap->getDataPtr();
     mInBufSize = mInTotalSize;

     mOutBufSize = StreamingZipInflater::OUTPUT_CHUNK_SIZE;
     mOutBuf = new uint8_t[mOutBufSize];

     initInflateState();
 }

 StreamingZipInflater::~StreamingZipInflater() {
     // tear down the in-flight zip state just in case
     ::inflateEnd(&mInflateState);

     if (mDataMap == NULL) {
         delete [] mInBuf;
     }
     delete [] mOutBuf;
 }

 void StreamingZipInflater::initInflateState() {
     ALOGV("Initializing inflate state");

     memset(&mInflateState, 0, sizeof(mInflateState));
     mInflateState.zalloc = Z_NULL;
     mInflateState.zfree = Z_NULL;
     mInflateState.opaque = Z_NULL;
     mInflateState.next_in = (Bytef*)mInBuf;
     mInflateState.next_out = (Bytef*) mOutBuf;
     mInflateState.avail_out = mOutBufSize;
     mInflateState.data_type = Z_UNKNOWN;

     mOutLastDecoded = mOutDeliverable = mOutCurPosition = 0;
     mInNextChunkOffset = 0;
     mStreamNeedsInit = true;

     if (mDataMap == NULL) {
         ::lseek(mFd, mInFileStart, SEEK_SET);
         mInflateState.avail_in = 0; // set when a chunk is read in
     } else {
         mInflateState.avail_in = mInBufSize;
     }
 }

 /*
  * Basic approach:
  *
  * 1. If we have undelivered uncompressed data, send it.  At this point
  *    either we've satisfied the request, or we've exhausted the available
  *    output data in mOutBuf.
  *
  * 2. While we haven't sent enough data to satisfy the request:
  *    0. if the request is for more data than exists, bail.
  *    a. if there is no input data to decode, read some into the input buffer
  *       and readjust the z_stream input pointers
  *    b. point the output to the start of the output buffer and decode what we can
  *    c. deliver whatever output data we can
  */
 ssize_t StreamingZipInflater::read(void* outBuf, size_t count) {
     uint8_t* dest = (uint8_t*) outBuf;
     size_t bytesRead = 0;
     size_t toRead = min_of(count, size_t(mOutTotalSize - mOutCurPosition));
     while (toRead > 0) {
         // First, write from whatever we already have decoded and ready to go
         size_t deliverable = min_of(toRead, mOutLastDecoded - mOutDeliverable);
         if (deliverable > 0) {
             if (outBuf != NULL) memcpy(dest, mOutBuf + mOutDeliverable, deliverable);
             mOutDeliverable += deliverable;
             mOutCurPosition += deliverable;
             dest += deliverable;
             bytesRead += deliverable;
             toRead -= deliverable;
         }

         // need more data?  time to decode some.
         if (toRead > 0) {
             // if we don't have any data to decode, read some in.  If we're working
             // from mmapped data this won't happen, because the clipping to total size
             // will prevent reading off the end of the mapped input chunk.
             if ((mInflateState.avail_in == 0) && (mDataMap == NULL)) {
                 int err = readNextChunk();
                 if (err < 0) {
                     ALOGE("Unable to access asset data: %d", err);
                     if (!mStreamNeedsInit) {
                         ::inflateEnd(&mInflateState);
                         initInflateState();
                     }
                     return -1;
                 }
             }
             // we know we've drained whatever is in the out buffer now, so just
             // start from scratch there, reading all the input we have at present.
             mInflateState.next_out = (Bytef*) mOutBuf;
             mInflateState.avail_out = mOutBufSize;

             /*
             ALOGV("Inflating to outbuf: avail_in=%u avail_out=%u next_in=%p next_out=%p",
                     mInflateState.avail_in, mInflateState.avail_out,
                     mInflateState.next_in, mInflateState.next_out);
             */
             int result = Z_OK;
             if (mStreamNeedsInit) {
                 ALOGV("Initializing zlib to inflate");
                 result = inflateInit2(&mInflateState, -MAX_WBITS);
                 mStreamNeedsInit = false;
             }
             if (result == Z_OK) result = ::inflate(&mInflateState, Z_SYNC_FLUSH);
             if (result < 0) {
                 // Whoops, inflation failed
                 ALOGE("Error inflating asset: %d", result);
                 ::inflateEnd(&mInflateState);
                 initInflateState();
                 return -1;
             } else {
                 if (result == Z_STREAM_END) {
                     // we know we have to have reached the target size here and will
                     // not try to read any further, so just wind things up.
                     ::inflateEnd(&mInflateState);
                 }

                 // Note how much data we got, and off we go
                 mOutDeliverable = 0;
                 mOutLastDecoded = mOutBufSize - mInflateState.avail_out;
             }
         }
     }
     return bytesRead;
 }

 int StreamingZipInflater::readNextChunk() {
     assert(mDataMap == NULL);

     if (mInNextChunkOffset < mInTotalSize) {
         size_t toRead = min_of(mInBufSize, mInTotalSize - mInNextChunkOffset);
         if (toRead > 0) {
             ssize_t didRead = TEMP_FAILURE_RETRY(::read(mFd, mInBuf, toRead));
             if (kIsDebug) {
                 ALOGV("Reading input chunk, size %08zx didread %08zx", toRead, didRead);
             }
             if (didRead < 0) {
                 ALOGE("Error reading asset data: %s", strerror(errno));
                 return didRead;
             } else {
                 mInNextChunkOffset += didRead;
                 mInflateState.next_in = (Bytef*) mInBuf;
                 mInflateState.avail_in = didRead;
             }
         }
     }
     return 0;
 }

 // seeking backwards requires uncompressing fom the beginning, so is very
 // expensive.  seeking forwards only requires uncompressing from the current
 // position to the destination.
 off64_t StreamingZipInflater::seekAbsolute(off64_t absoluteInputPosition) {
     if (absoluteInputPosition < mOutCurPosition) {
         // rewind and reprocess the data from the beginning
         if (!mStreamNeedsInit) {
             ::inflateEnd(&mInflateState);
         }
         initInflateState();
         read(NULL, absoluteInputPosition);
     } else if (absoluteInputPosition > mOutCurPosition) {
         read(NULL, absoluteInputPosition - mOutCurPosition);
     }
     // else if the target position *is* our current position, do nothing
     return absoluteInputPosition;
 }
	/*
	* 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.
	*/

	//#define LOG_NDEBUG 0
	#define LOG_TAG "szipinf"
	#include <utils/Log.h>

	#include <androidfw/StreamingZipInflater.h>
	#include <utils/FileMap.h>
	#include <string.h>
	#include <stddef.h>
	#include <assert.h>
	#include <unistd.h>
	#include <errno.h>

	/*
	* TEMP_FAILURE_RETRY is defined by some, but not all, versions of
	* <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
	* not already defined, then define it here.
	*/
	#ifndef TEMP_FAILURE_RETRY
	/* Used to retry syscalls that can return EINTR. */
	#define TEMP_FAILURE_RETRY(exp) ({ \
	typeof (exp) _rc; \
	do { \
	_rc = (exp); \
	} while (_rc == -1 && errno == EINTR); \
	_rc; })
	#endif

	static const bool kIsDebug = false;

	static inline size_t min_of(size_t a, size_t b) { return (a < b) ? a : b; }

	using namespace android;

	/*
	* Streaming access to compressed asset data in an open fd
	*/
	StreamingZipInflater::StreamingZipInflater(int fd, off64_t compDataStart,
	size_t uncompSize, size_t compSize) {
	mFd = fd;
	mDataMap = NULL;
	mInFileStart = compDataStart;
	mOutTotalSize = uncompSize;
	mInTotalSize = compSize;

	mInBufSize = StreamingZipInflater::INPUT_CHUNK_SIZE;
	mInBuf = new uint8_t[mInBufSize];

	mOutBufSize = StreamingZipInflater::OUTPUT_CHUNK_SIZE;
	mOutBuf = new uint8_t[mOutBufSize];

	initInflateState();
	}

	/*
	* Streaming access to compressed data held in an mmapped region of memory
	*/
	StreamingZipInflater::StreamingZipInflater(FileMap* dataMap, size_t uncompSize) {
	mFd = -1;
	mDataMap = dataMap;
	mOutTotalSize = uncompSize;
	mInTotalSize = dataMap->getDataLength();

	mInBuf = (uint8_t*) dataMap->getDataPtr();
	mInBufSize = mInTotalSize;

	mOutBufSize = StreamingZipInflater::OUTPUT_CHUNK_SIZE;
	mOutBuf = new uint8_t[mOutBufSize];

	initInflateState();
	}

	StreamingZipInflater::~StreamingZipInflater() {
	// tear down the in-flight zip state just in case
	::inflateEnd(&mInflateState);

	if (mDataMap == NULL) {
	delete [] mInBuf;
	}
	delete [] mOutBuf;
	}

	void StreamingZipInflater::initInflateState() {
	ALOGV("Initializing inflate state");

	memset(&mInflateState, 0, sizeof(mInflateState));
	mInflateState.zalloc = Z_NULL;
	mInflateState.zfree = Z_NULL;
	mInflateState.opaque = Z_NULL;
	mInflateState.next_in = (Bytef*)mInBuf;
	mInflateState.next_out = (Bytef*) mOutBuf;
	mInflateState.avail_out = mOutBufSize;
	mInflateState.data_type = Z_UNKNOWN;

	mOutLastDecoded = mOutDeliverable = mOutCurPosition = 0;
	mInNextChunkOffset = 0;
	mStreamNeedsInit = true;

	if (mDataMap == NULL) {
	::lseek(mFd, mInFileStart, SEEK_SET);
	mInflateState.avail_in = 0; // set when a chunk is read in
	} else {
	mInflateState.avail_in = mInBufSize;
	}
	}

	/*
	* Basic approach:
	*
	* 1. If we have undelivered uncompressed data, send it. At this point
	* either we've satisfied the request, or we've exhausted the available
	* output data in mOutBuf.
	*
	* 2. While we haven't sent enough data to satisfy the request:
	* 0. if the request is for more data than exists, bail.
	* a. if there is no input data to decode, read some into the input buffer
	* and readjust the z_stream input pointers
	* b. point the output to the start of the output buffer and decode what we can
	* c. deliver whatever output data we can
	*/
	ssize_t StreamingZipInflater::read(void* outBuf, size_t count) {
	uint8_t* dest = (uint8_t*) outBuf;
	size_t bytesRead = 0;
	size_t toRead = min_of(count, size_t(mOutTotalSize - mOutCurPosition));
	while (toRead > 0) {
	// First, write from whatever we already have decoded and ready to go
	size_t deliverable = min_of(toRead, mOutLastDecoded - mOutDeliverable);
	if (deliverable > 0) {
	if (outBuf != NULL) memcpy(dest, mOutBuf + mOutDeliverable, deliverable);
	mOutDeliverable += deliverable;
	mOutCurPosition += deliverable;
	dest += deliverable;
	bytesRead += deliverable;
	toRead -= deliverable;
	}

	// need more data? time to decode some.
	if (toRead > 0) {
	// if we don't have any data to decode, read some in. If we're working
	// from mmapped data this won't happen, because the clipping to total size
	// will prevent reading off the end of the mapped input chunk.
	if ((mInflateState.avail_in == 0) && (mDataMap == NULL)) {
	int err = readNextChunk();
	if (err < 0) {
	ALOGE("Unable to access asset data: %d", err);
	if (!mStreamNeedsInit) {
	::inflateEnd(&mInflateState);
	initInflateState();
	}
	return -1;
	}
	}
	// we know we've drained whatever is in the out buffer now, so just
	// start from scratch there, reading all the input we have at present.
	mInflateState.next_out = (Bytef*) mOutBuf;
	mInflateState.avail_out = mOutBufSize;

	/*
	ALOGV("Inflating to outbuf: avail_in=%u avail_out=%u next_in=%p next_out=%p",
	mInflateState.avail_in, mInflateState.avail_out,
	mInflateState.next_in, mInflateState.next_out);
	*/
	int result = Z_OK;
	if (mStreamNeedsInit) {
	ALOGV("Initializing zlib to inflate");
	result = inflateInit2(&mInflateState, -MAX_WBITS);
	mStreamNeedsInit = false;
	}
	if (result == Z_OK) result = ::inflate(&mInflateState, Z_SYNC_FLUSH);
	if (result < 0) {
	// Whoops, inflation failed
	ALOGE("Error inflating asset: %d", result);
	::inflateEnd(&mInflateState);
	initInflateState();
	return -1;
	} else {
	if (result == Z_STREAM_END) {
	// we know we have to have reached the target size here and will
	// not try to read any further, so just wind things up.
	::inflateEnd(&mInflateState);
	}

	// Note how much data we got, and off we go
	mOutDeliverable = 0;
	mOutLastDecoded = mOutBufSize - mInflateState.avail_out;
	}
	}
	}
	return bytesRead;
	}

	int StreamingZipInflater::readNextChunk() {
	assert(mDataMap == NULL);

	if (mInNextChunkOffset < mInTotalSize) {
	size_t toRead = min_of(mInBufSize, mInTotalSize - mInNextChunkOffset);
	if (toRead > 0) {
	ssize_t didRead = TEMP_FAILURE_RETRY(::read(mFd, mInBuf, toRead));
	if (kIsDebug) {
	ALOGV("Reading input chunk, size %08zx didread %08zx", toRead, didRead);
	}
	if (didRead < 0) {
	ALOGE("Error reading asset data: %s", strerror(errno));
	return didRead;
	} else {
	mInNextChunkOffset += didRead;
	mInflateState.next_in = (Bytef*) mInBuf;
	mInflateState.avail_in = didRead;
	}
	}
	}
	return 0;
	}

	// seeking backwards requires uncompressing fom the beginning, so is very
	// expensive. seeking forwards only requires uncompressing from the current
	// position to the destination.
	off64_t StreamingZipInflater::seekAbsolute(off64_t absoluteInputPosition) {
	if (absoluteInputPosition < mOutCurPosition) {
	// rewind and reprocess the data from the beginning
	if (!mStreamNeedsInit) {
	::inflateEnd(&mInflateState);
	}
	initInflateState();
	read(NULL, absoluteInputPosition);
	} else if (absoluteInputPosition > mOutCurPosition) {
	read(NULL, absoluteInputPosition - mOutCurPosition);
	}
	// else if the target position is our current position, do nothing
	return absoluteInputPosition;
	}