343 lines
9.4 KiB
C++
343 lines
9.4 KiB
C++
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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//
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// Misc zip/gzip utility functions.
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//
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#define LOG_TAG "ziputil"
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#include <utils/ZipUtils.h>
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#include <utils/ZipFileRO.h>
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#include <utils/Log.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <zlib.h>
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using namespace android;
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/*
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* Utility function that expands zip/gzip "deflate" compressed data
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* into a buffer.
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*
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* "fd" is an open file positioned at the start of the "deflate" data
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* "buf" must hold at least "uncompressedLen" bytes.
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*/
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/*static*/ bool ZipUtils::inflateToBuffer(int fd, void* buf,
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long uncompressedLen, long compressedLen)
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{
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bool result = false;
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const unsigned long kReadBufSize = 32768;
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unsigned char* readBuf = NULL;
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z_stream zstream;
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int zerr;
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unsigned long compRemaining;
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assert(uncompressedLen >= 0);
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assert(compressedLen >= 0);
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readBuf = new unsigned char[kReadBufSize];
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if (readBuf == NULL)
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goto bail;
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compRemaining = compressedLen;
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/*
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* Initialize the zlib stream.
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*/
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memset(&zstream, 0, sizeof(zstream));
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zstream.zalloc = Z_NULL;
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zstream.zfree = Z_NULL;
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zstream.opaque = Z_NULL;
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zstream.next_in = NULL;
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zstream.avail_in = 0;
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zstream.next_out = (Bytef*) buf;
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zstream.avail_out = uncompressedLen;
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zstream.data_type = Z_UNKNOWN;
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/*
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* Use the undocumented "negative window bits" feature to tell zlib
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* that there's no zlib header waiting for it.
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*/
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zerr = inflateInit2(&zstream, -MAX_WBITS);
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if (zerr != Z_OK) {
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if (zerr == Z_VERSION_ERROR) {
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LOGE("Installed zlib is not compatible with linked version (%s)\n",
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ZLIB_VERSION);
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} else {
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LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
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}
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goto bail;
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}
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/*
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* Loop while we have data.
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*/
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do {
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unsigned long getSize;
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/* read as much as we can */
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if (zstream.avail_in == 0) {
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getSize = (compRemaining > kReadBufSize) ?
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kReadBufSize : compRemaining;
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LOGV("+++ reading %ld bytes (%ld left)\n",
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getSize, compRemaining);
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int cc = read(fd, readBuf, getSize);
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if (cc != (int) getSize) {
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LOGD("inflate read failed (%d vs %ld)\n",
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cc, getSize);
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goto z_bail;
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}
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compRemaining -= getSize;
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zstream.next_in = readBuf;
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zstream.avail_in = getSize;
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}
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/* uncompress the data */
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zerr = inflate(&zstream, Z_NO_FLUSH);
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if (zerr != Z_OK && zerr != Z_STREAM_END) {
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LOGD("zlib inflate call failed (zerr=%d)\n", zerr);
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goto z_bail;
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}
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/* output buffer holds all, so no need to write the output */
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} while (zerr == Z_OK);
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assert(zerr == Z_STREAM_END); /* other errors should've been caught */
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if ((long) zstream.total_out != uncompressedLen) {
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LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
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zstream.total_out, uncompressedLen);
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goto z_bail;
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}
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// success!
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result = true;
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z_bail:
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inflateEnd(&zstream); /* free up any allocated structures */
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bail:
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delete[] readBuf;
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return result;
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}
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/*
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* Utility function that expands zip/gzip "deflate" compressed data
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* into a buffer.
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*
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* (This is a clone of the previous function, but it takes a FILE* instead
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* of an fd. We could pass fileno(fd) to the above, but we can run into
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* trouble when "fp" has a different notion of what fd's file position is.)
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*
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* "fp" is an open file positioned at the start of the "deflate" data
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* "buf" must hold at least "uncompressedLen" bytes.
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*/
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/*static*/ bool ZipUtils::inflateToBuffer(FILE* fp, void* buf,
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long uncompressedLen, long compressedLen)
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{
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bool result = false;
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const unsigned long kReadBufSize = 32768;
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unsigned char* readBuf = NULL;
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z_stream zstream;
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int zerr;
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unsigned long compRemaining;
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assert(uncompressedLen >= 0);
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assert(compressedLen >= 0);
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readBuf = new unsigned char[kReadBufSize];
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if (readBuf == NULL)
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goto bail;
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compRemaining = compressedLen;
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/*
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* Initialize the zlib stream.
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*/
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memset(&zstream, 0, sizeof(zstream));
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zstream.zalloc = Z_NULL;
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zstream.zfree = Z_NULL;
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zstream.opaque = Z_NULL;
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zstream.next_in = NULL;
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zstream.avail_in = 0;
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zstream.next_out = (Bytef*) buf;
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zstream.avail_out = uncompressedLen;
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zstream.data_type = Z_UNKNOWN;
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/*
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* Use the undocumented "negative window bits" feature to tell zlib
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* that there's no zlib header waiting for it.
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*/
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zerr = inflateInit2(&zstream, -MAX_WBITS);
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if (zerr != Z_OK) {
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if (zerr == Z_VERSION_ERROR) {
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LOGE("Installed zlib is not compatible with linked version (%s)\n",
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ZLIB_VERSION);
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} else {
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LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
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}
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goto bail;
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}
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/*
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* Loop while we have data.
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*/
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do {
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unsigned long getSize;
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/* read as much as we can */
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if (zstream.avail_in == 0) {
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getSize = (compRemaining > kReadBufSize) ?
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kReadBufSize : compRemaining;
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LOGV("+++ reading %ld bytes (%ld left)\n",
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getSize, compRemaining);
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int cc = fread(readBuf, 1, getSize, fp);
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if (cc != (int) getSize) {
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LOGD("inflate read failed (%d vs %ld)\n",
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cc, getSize);
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goto z_bail;
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}
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compRemaining -= getSize;
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zstream.next_in = readBuf;
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zstream.avail_in = getSize;
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}
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/* uncompress the data */
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zerr = inflate(&zstream, Z_NO_FLUSH);
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if (zerr != Z_OK && zerr != Z_STREAM_END) {
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LOGD("zlib inflate call failed (zerr=%d)\n", zerr);
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goto z_bail;
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}
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/* output buffer holds all, so no need to write the output */
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} while (zerr == Z_OK);
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assert(zerr == Z_STREAM_END); /* other errors should've been caught */
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if ((long) zstream.total_out != uncompressedLen) {
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LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
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zstream.total_out, uncompressedLen);
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goto z_bail;
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}
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// success!
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result = true;
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z_bail:
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inflateEnd(&zstream); /* free up any allocated structures */
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bail:
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delete[] readBuf;
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return result;
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}
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/*
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* Look at the contents of a gzip archive. We want to know where the
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* data starts, and how long it will be after it is uncompressed.
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*
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* We expect to find the CRC and length as the last 8 bytes on the file.
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* This is a pretty reasonable thing to expect for locally-compressed
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* files, but there's a small chance that some extra padding got thrown
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* on (the man page talks about compressed data written to tape). We
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* don't currently deal with that here. If "gzip -l" whines, we're going
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* to fail too.
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*
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* On exit, "fp" is pointing at the start of the compressed data.
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*/
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/*static*/ bool ZipUtils::examineGzip(FILE* fp, int* pCompressionMethod,
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long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32)
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{
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enum { // flags
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FTEXT = 0x01,
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FHCRC = 0x02,
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FEXTRA = 0x04,
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FNAME = 0x08,
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FCOMMENT = 0x10,
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};
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int ic;
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int method, flags;
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int i;
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ic = getc(fp);
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if (ic != 0x1f || getc(fp) != 0x8b)
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return false; // not gzip
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method = getc(fp);
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flags = getc(fp);
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/* quick sanity checks */
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if (method == EOF || flags == EOF)
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return false;
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if (method != ZipFileRO::kCompressDeflated)
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return false;
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/* skip over 4 bytes of mod time, 1 byte XFL, 1 byte OS */
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for (i = 0; i < 6; i++)
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(void) getc(fp);
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/* consume "extra" field, if present */
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if ((flags & FEXTRA) != 0) {
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int len;
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len = getc(fp);
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len |= getc(fp) << 8;
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while (len-- && getc(fp) != EOF)
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;
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}
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/* consume filename, if present */
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if ((flags & FNAME) != 0) {
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do {
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ic = getc(fp);
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} while (ic != 0 && ic != EOF);
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}
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/* consume comment, if present */
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if ((flags & FCOMMENT) != 0) {
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do {
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ic = getc(fp);
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} while (ic != 0 && ic != EOF);
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}
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/* consume 16-bit header CRC, if present */
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if ((flags & FHCRC) != 0) {
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(void) getc(fp);
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(void) getc(fp);
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}
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if (feof(fp) || ferror(fp))
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return false;
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/* seek to the end; CRC and length are in the last 8 bytes */
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long curPosn = ftell(fp);
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unsigned char buf[8];
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fseek(fp, -8, SEEK_END);
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*pCompressedLen = ftell(fp) - curPosn;
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if (fread(buf, 1, 8, fp) != 8)
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return false;
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/* seek back to start of compressed data */
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fseek(fp, curPosn, SEEK_SET);
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*pCompressionMethod = method;
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*pCRC32 = ZipFileRO::get4LE(&buf[0]);
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*pUncompressedLen = ZipFileRO::get4LE(&buf[4]);
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return true;
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}
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