725 lines
21 KiB
C++
725 lines
21 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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// Read-only access to Zip archives, with minimal heap allocation.
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//
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#define LOG_TAG "zipro"
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//#define LOG_NDEBUG 0
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#include "utils/ZipFileRO.h"
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#include "utils/Log.h"
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#include "utils/misc.h"
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#include <zlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <assert.h>
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using namespace android;
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/*
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* Zip file constants.
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*/
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#define kEOCDSignature 0x06054b50
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#define kEOCDLen 22
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#define kEOCDNumEntries 8 // offset to #of entries in file
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#define kEOCDFileOffset 16 // offset to central directory
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#define kMaxCommentLen 65535 // longest possible in ushort
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#define kMaxEOCDSearch (kMaxCommentLen + kEOCDLen)
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#define kLFHSignature 0x04034b50
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#define kLFHLen 30 // excluding variable-len fields
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#define kLFHNameLen 26 // offset to filename length
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#define kLFHExtraLen 28 // offset to extra length
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#define kCDESignature 0x02014b50
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#define kCDELen 46 // excluding variable-len fields
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#define kCDEMethod 10 // offset to compression method
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#define kCDEModWhen 12 // offset to modification timestamp
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#define kCDECRC 16 // offset to entry CRC
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#define kCDECompLen 20 // offset to compressed length
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#define kCDEUncompLen 24 // offset to uncompressed length
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#define kCDENameLen 28 // offset to filename length
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#define kCDEExtraLen 30 // offset to extra length
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#define kCDECommentLen 32 // offset to comment length
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#define kCDELocalOffset 42 // offset to local hdr
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/*
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* The values we return for ZipEntryRO use 0 as an invalid value, so we
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* want to adjust the hash table index by a fixed amount. Using a large
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* value helps insure that people don't mix & match arguments, e.g. to
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* findEntryByIndex().
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*/
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#define kZipEntryAdj 10000
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/*
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* Convert a ZipEntryRO to a hash table index, verifying that it's in a
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* valid range.
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*/
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int ZipFileRO::entryToIndex(const ZipEntryRO entry) const
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{
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long ent = ((long) entry) - kZipEntryAdj;
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if (ent < 0 || ent >= mHashTableSize || mHashTable[ent].name == NULL) {
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LOGW("Invalid ZipEntryRO %p (%ld)\n", entry, ent);
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return -1;
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}
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return ent;
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}
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/*
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* Open the specified file read-only. We memory-map the entire thing and
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* close the file before returning.
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*/
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status_t ZipFileRO::open(const char* zipFileName)
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{
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int fd = -1;
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off_t length;
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assert(mFileMap == NULL);
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/*
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* Open and map the specified file.
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*/
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fd = ::open(zipFileName, O_RDONLY);
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if (fd < 0) {
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LOGW("Unable to open zip '%s': %s\n", zipFileName, strerror(errno));
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return NAME_NOT_FOUND;
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}
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length = lseek(fd, 0, SEEK_END);
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if (length < 0) {
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close(fd);
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return UNKNOWN_ERROR;
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}
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mFileMap = new FileMap();
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if (mFileMap == NULL) {
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close(fd);
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return NO_MEMORY;
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}
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if (!mFileMap->create(zipFileName, fd, 0, length, true)) {
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LOGW("Unable to map '%s': %s\n", zipFileName, strerror(errno));
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close(fd);
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return UNKNOWN_ERROR;
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}
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mFd = fd;
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/*
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* Got it mapped, verify it and create data structures for fast access.
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*/
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if (!parseZipArchive()) {
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mFileMap->release();
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mFileMap = NULL;
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return UNKNOWN_ERROR;
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}
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return OK;
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}
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/*
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* Parse the Zip archive, verifying its contents and initializing internal
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* data structures.
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*/
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bool ZipFileRO::parseZipArchive(void)
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{
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#define CHECK_OFFSET(_off) { \
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if ((unsigned int) (_off) >= maxOffset) { \
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LOGE("ERROR: bad offset %u (max %d): %s\n", \
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(unsigned int) (_off), maxOffset, #_off); \
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goto bail; \
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} \
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}
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const unsigned char* basePtr = (const unsigned char*)mFileMap->getDataPtr();
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const unsigned char* ptr;
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size_t length = mFileMap->getDataLength();
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bool result = false;
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unsigned int i, numEntries, cdOffset;
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unsigned int val;
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/*
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* The first 4 bytes of the file will either be the local header
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* signature for the first file (kLFHSignature) or, if the archive doesn't
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* have any files in it, the end-of-central-directory signature
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* (kEOCDSignature).
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*/
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val = get4LE(basePtr);
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if (val == kEOCDSignature) {
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LOGI("Found Zip archive, but it looks empty\n");
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goto bail;
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} else if (val != kLFHSignature) {
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LOGV("Not a Zip archive (found 0x%08x)\n", val);
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goto bail;
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}
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/*
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* Find the EOCD. We'll find it immediately unless they have a file
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* comment.
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*/
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ptr = basePtr + length - kEOCDLen;
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while (ptr >= basePtr) {
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if (*ptr == (kEOCDSignature & 0xff) && get4LE(ptr) == kEOCDSignature)
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break;
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ptr--;
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}
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if (ptr < basePtr) {
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LOGI("Could not find end-of-central-directory in Zip\n");
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goto bail;
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}
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/*
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* There are two interesting items in the EOCD block: the number of
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* entries in the file, and the file offset of the start of the
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* central directory.
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*
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* (There's actually a count of the #of entries in this file, and for
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* all files which comprise a spanned archive, but for our purposes
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* we're only interested in the current file. Besides, we expect the
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* two to be equivalent for our stuff.)
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*/
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numEntries = get2LE(ptr + kEOCDNumEntries);
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cdOffset = get4LE(ptr + kEOCDFileOffset);
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/* valid offsets are [0,EOCD] */
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unsigned int maxOffset;
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maxOffset = (ptr - basePtr) +1;
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LOGV("+++ numEntries=%d cdOffset=%d\n", numEntries, cdOffset);
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if (numEntries == 0 || cdOffset >= length) {
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LOGW("Invalid entries=%d offset=%d (len=%zd)\n",
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numEntries, cdOffset, length);
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goto bail;
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}
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/*
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* Create hash table. We have a minimum 75% load factor, possibly as
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* low as 50% after we round off to a power of 2.
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*/
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mNumEntries = numEntries;
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mHashTableSize = roundUpPower2(1 + ((numEntries * 4) / 3));
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mHashTable = (HashEntry*) calloc(1, sizeof(HashEntry) * mHashTableSize);
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/*
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* Walk through the central directory, adding entries to the hash
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* table.
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*/
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ptr = basePtr + cdOffset;
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for (i = 0; i < numEntries; i++) {
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unsigned int fileNameLen, extraLen, commentLen, localHdrOffset;
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const unsigned char* localHdr;
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unsigned int hash;
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if (get4LE(ptr) != kCDESignature) {
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LOGW("Missed a central dir sig (at %d)\n", i);
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goto bail;
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}
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if (ptr + kCDELen > basePtr + length) {
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LOGW("Ran off the end (at %d)\n", i);
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goto bail;
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}
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localHdrOffset = get4LE(ptr + kCDELocalOffset);
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CHECK_OFFSET(localHdrOffset);
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fileNameLen = get2LE(ptr + kCDENameLen);
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extraLen = get2LE(ptr + kCDEExtraLen);
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commentLen = get2LE(ptr + kCDECommentLen);
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//LOGV("+++ %d: localHdr=%d fnl=%d el=%d cl=%d\n",
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// i, localHdrOffset, fileNameLen, extraLen, commentLen);
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//LOGV(" '%.*s'\n", fileNameLen, ptr + kCDELen);
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/* add the CDE filename to the hash table */
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hash = computeHash((const char*)ptr + kCDELen, fileNameLen);
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addToHash((const char*)ptr + kCDELen, fileNameLen, hash);
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localHdr = basePtr + localHdrOffset;
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if (get4LE(localHdr) != kLFHSignature) {
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LOGW("Bad offset to local header: %d (at %d)\n",
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localHdrOffset, i);
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goto bail;
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}
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ptr += kCDELen + fileNameLen + extraLen + commentLen;
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CHECK_OFFSET(ptr - basePtr);
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}
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result = true;
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bail:
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return result;
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#undef CHECK_OFFSET
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}
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/*
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* Simple string hash function for non-null-terminated strings.
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*/
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/*static*/ unsigned int ZipFileRO::computeHash(const char* str, int len)
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{
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unsigned int hash = 0;
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while (len--)
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hash = hash * 31 + *str++;
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return hash;
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}
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/*
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* Add a new entry to the hash table.
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*/
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void ZipFileRO::addToHash(const char* str, int strLen, unsigned int hash)
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{
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int ent = hash & (mHashTableSize-1);
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/*
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* We over-allocate the table, so we're guaranteed to find an empty slot.
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*/
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while (mHashTable[ent].name != NULL)
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ent = (ent + 1) & (mHashTableSize-1);
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mHashTable[ent].name = str;
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mHashTable[ent].nameLen = strLen;
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}
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/*
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* Find a matching entry.
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*
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* Returns 0 if not found.
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*/
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ZipEntryRO ZipFileRO::findEntryByName(const char* fileName) const
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{
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int nameLen = strlen(fileName);
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unsigned int hash = computeHash(fileName, nameLen);
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int ent = hash & (mHashTableSize-1);
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while (mHashTable[ent].name != NULL) {
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if (mHashTable[ent].nameLen == nameLen &&
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memcmp(mHashTable[ent].name, fileName, nameLen) == 0)
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{
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/* match */
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return (ZipEntryRO) (ent + kZipEntryAdj);
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}
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ent = (ent + 1) & (mHashTableSize-1);
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}
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return NULL;
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}
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/*
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* Find the Nth entry.
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*
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* This currently involves walking through the sparse hash table, counting
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* non-empty entries. If we need to speed this up we can either allocate
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* a parallel lookup table or (perhaps better) provide an iterator interface.
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*/
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ZipEntryRO ZipFileRO::findEntryByIndex(int idx) const
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{
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if (idx < 0 || idx >= mNumEntries) {
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LOGW("Invalid index %d\n", idx);
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return NULL;
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}
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for (int ent = 0; ent < mHashTableSize; ent++) {
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if (mHashTable[ent].name != NULL) {
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if (idx-- == 0)
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return (ZipEntryRO) (ent + kZipEntryAdj);
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}
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}
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return NULL;
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}
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/*
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* Get the useful fields from the zip entry.
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*
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* Returns "false" if the offsets to the fields or the contents of the fields
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* appear to be bogus.
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*/
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bool ZipFileRO::getEntryInfo(ZipEntryRO entry, int* pMethod, long* pUncompLen,
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long* pCompLen, off_t* pOffset, long* pModWhen, long* pCrc32) const
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{
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int ent = entryToIndex(entry);
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if (ent < 0)
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return false;
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/*
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* Recover the start of the central directory entry from the filename
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* pointer.
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*/
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const unsigned char* basePtr = (const unsigned char*)mFileMap->getDataPtr();
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const unsigned char* ptr = (const unsigned char*) mHashTable[ent].name;
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size_t zipLength = mFileMap->getDataLength();
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ptr -= kCDELen;
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int method = get2LE(ptr + kCDEMethod);
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if (pMethod != NULL)
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*pMethod = method;
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if (pModWhen != NULL)
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*pModWhen = get4LE(ptr + kCDEModWhen);
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if (pCrc32 != NULL)
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*pCrc32 = get4LE(ptr + kCDECRC);
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/*
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* We need to make sure that the lengths are not so large that somebody
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* trying to map the compressed or uncompressed data runs off the end
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* of the mapped region.
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*/
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unsigned long localHdrOffset = get4LE(ptr + kCDELocalOffset);
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if (localHdrOffset + kLFHLen >= zipLength) {
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LOGE("ERROR: bad local hdr offset in zip\n");
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return false;
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}
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const unsigned char* localHdr = basePtr + localHdrOffset;
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off_t dataOffset = localHdrOffset + kLFHLen
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+ get2LE(localHdr + kLFHNameLen) + get2LE(localHdr + kLFHExtraLen);
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if ((unsigned long) dataOffset >= zipLength) {
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LOGE("ERROR: bad data offset in zip\n");
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return false;
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}
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if (pCompLen != NULL) {
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*pCompLen = get4LE(ptr + kCDECompLen);
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if (*pCompLen < 0 || (size_t)(dataOffset + *pCompLen) >= zipLength) {
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LOGE("ERROR: bad compressed length in zip\n");
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return false;
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}
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}
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if (pUncompLen != NULL) {
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*pUncompLen = get4LE(ptr + kCDEUncompLen);
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if (*pUncompLen < 0) {
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LOGE("ERROR: negative uncompressed length in zip\n");
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return false;
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}
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if (method == kCompressStored &&
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(size_t)(dataOffset + *pUncompLen) >= zipLength)
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{
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LOGE("ERROR: bad uncompressed length in zip\n");
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return false;
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}
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}
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if (pOffset != NULL) {
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*pOffset = dataOffset;
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}
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return true;
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}
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/*
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* Copy the entry's filename to the buffer.
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*/
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int ZipFileRO::getEntryFileName(ZipEntryRO entry, char* buffer, int bufLen)
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const
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{
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int ent = entryToIndex(entry);
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if (ent < 0)
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return -1;
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int nameLen = mHashTable[ent].nameLen;
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if (bufLen < nameLen+1)
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return nameLen+1;
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memcpy(buffer, mHashTable[ent].name, nameLen);
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buffer[nameLen] = '\0';
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return 0;
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}
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/*
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* Create a new FileMap object that spans the data in "entry".
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*/
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FileMap* ZipFileRO::createEntryFileMap(ZipEntryRO entry) const
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{
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/*
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* TODO: the efficient way to do this is to modify FileMap to allow
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* sub-regions of a file to be mapped. A reference-counting scheme
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* can manage the base memory mapping. For now, we just create a brand
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* new mapping off of the Zip archive file descriptor.
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*/
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FileMap* newMap;
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long compLen;
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off_t offset;
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if (!getEntryInfo(entry, NULL, NULL, &compLen, &offset, NULL, NULL))
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return NULL;
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newMap = new FileMap();
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if (!newMap->create(mFileMap->getFileName(), mFd, offset, compLen, true)) {
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newMap->release();
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return NULL;
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}
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return newMap;
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}
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/*
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* Uncompress an entry, in its entirety, into the provided output buffer.
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*
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* This doesn't verify the data's CRC, which might be useful for
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* uncompressed data. The caller should be able to manage it.
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*/
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bool ZipFileRO::uncompressEntry(ZipEntryRO entry, void* buffer) const
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{
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const int kSequentialMin = 32768;
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bool result = false;
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int ent = entryToIndex(entry);
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if (ent < 0)
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return -1;
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const unsigned char* basePtr = (const unsigned char*)mFileMap->getDataPtr();
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int method;
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long uncompLen, compLen;
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off_t offset;
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getEntryInfo(entry, &method, &uncompLen, &compLen, &offset, NULL, NULL);
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/*
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* Experiment with madvise hint. When we want to uncompress a file,
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* we pull some stuff out of the central dir entry and then hit a
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* bunch of compressed or uncompressed data sequentially. The CDE
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* visit will cause a limited amount of read-ahead because it's at
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* the end of the file. We could end up doing lots of extra disk
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* access if the file we're prying open is small. Bottom line is we
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* probably don't want to turn MADV_SEQUENTIAL on and leave it on.
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*
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* So, if the compressed size of the file is above a certain minimum
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* size, temporarily boost the read-ahead in the hope that the extra
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* pair of system calls are negated by a reduction in page faults.
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*/
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if (compLen > kSequentialMin)
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mFileMap->advise(FileMap::SEQUENTIAL);
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if (method == kCompressStored) {
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memcpy(buffer, basePtr + offset, uncompLen);
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} else {
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if (!inflateBuffer(buffer, basePtr + offset, uncompLen, compLen))
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goto bail;
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}
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if (compLen > kSequentialMin)
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mFileMap->advise(FileMap::NORMAL);
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result = true;
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bail:
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return result;
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}
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/*
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* Uncompress an entry, in its entirety, to an open file descriptor.
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*
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* This doesn't verify the data's CRC, but probably should.
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*/
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bool ZipFileRO::uncompressEntry(ZipEntryRO entry, int fd) const
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{
|
|
bool result = false;
|
|
int ent = entryToIndex(entry);
|
|
if (ent < 0)
|
|
return -1;
|
|
|
|
const unsigned char* basePtr = (const unsigned char*)mFileMap->getDataPtr();
|
|
int method;
|
|
long uncompLen, compLen;
|
|
off_t offset;
|
|
|
|
getEntryInfo(entry, &method, &uncompLen, &compLen, &offset, NULL, NULL);
|
|
|
|
if (method == kCompressStored) {
|
|
ssize_t actual;
|
|
|
|
actual = write(fd, basePtr + offset, uncompLen);
|
|
if (actual < 0) {
|
|
LOGE("Write failed: %s\n", strerror(errno));
|
|
goto bail;
|
|
} else if (actual != uncompLen) {
|
|
LOGE("Partial write during uncompress (%d of %ld)\n",
|
|
(int)actual, uncompLen);
|
|
goto bail;
|
|
} else {
|
|
LOGI("+++ successful write\n");
|
|
}
|
|
} else {
|
|
if (!inflateBuffer(fd, basePtr+offset, uncompLen, compLen))
|
|
goto bail;
|
|
}
|
|
|
|
result = true;
|
|
|
|
bail:
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Uncompress "deflate" data from one buffer to another.
|
|
*/
|
|
/*static*/ bool ZipFileRO::inflateBuffer(void* outBuf, const void* inBuf,
|
|
long uncompLen, long compLen)
|
|
{
|
|
bool result = false;
|
|
z_stream zstream;
|
|
int zerr;
|
|
|
|
/*
|
|
* Initialize the zlib stream struct.
|
|
*/
|
|
memset(&zstream, 0, sizeof(zstream));
|
|
zstream.zalloc = Z_NULL;
|
|
zstream.zfree = Z_NULL;
|
|
zstream.opaque = Z_NULL;
|
|
zstream.next_in = (Bytef*)inBuf;
|
|
zstream.avail_in = compLen;
|
|
zstream.next_out = (Bytef*) outBuf;
|
|
zstream.avail_out = uncompLen;
|
|
zstream.data_type = Z_UNKNOWN;
|
|
|
|
/*
|
|
* Use the undocumented "negative window bits" feature to tell zlib
|
|
* that there's no zlib header waiting for it.
|
|
*/
|
|
zerr = inflateInit2(&zstream, -MAX_WBITS);
|
|
if (zerr != Z_OK) {
|
|
if (zerr == Z_VERSION_ERROR) {
|
|
LOGE("Installed zlib is not compatible with linked version (%s)\n",
|
|
ZLIB_VERSION);
|
|
} else {
|
|
LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
|
|
}
|
|
goto bail;
|
|
}
|
|
|
|
/*
|
|
* Expand data.
|
|
*/
|
|
zerr = inflate(&zstream, Z_FINISH);
|
|
if (zerr != Z_STREAM_END) {
|
|
LOGW("Zip inflate failed, zerr=%d (nIn=%p aIn=%u nOut=%p aOut=%u)\n",
|
|
zerr, zstream.next_in, zstream.avail_in,
|
|
zstream.next_out, zstream.avail_out);
|
|
goto z_bail;
|
|
}
|
|
|
|
/* paranoia */
|
|
if ((long) zstream.total_out != uncompLen) {
|
|
LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
|
|
zstream.total_out, uncompLen);
|
|
goto z_bail;
|
|
}
|
|
|
|
result = true;
|
|
|
|
z_bail:
|
|
inflateEnd(&zstream); /* free up any allocated structures */
|
|
|
|
bail:
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Uncompress "deflate" data from one buffer to an open file descriptor.
|
|
*/
|
|
/*static*/ bool ZipFileRO::inflateBuffer(int fd, const void* inBuf,
|
|
long uncompLen, long compLen)
|
|
{
|
|
bool result = false;
|
|
const int kWriteBufSize = 32768;
|
|
unsigned char writeBuf[kWriteBufSize];
|
|
z_stream zstream;
|
|
int zerr;
|
|
|
|
/*
|
|
* Initialize the zlib stream struct.
|
|
*/
|
|
memset(&zstream, 0, sizeof(zstream));
|
|
zstream.zalloc = Z_NULL;
|
|
zstream.zfree = Z_NULL;
|
|
zstream.opaque = Z_NULL;
|
|
zstream.next_in = (Bytef*)inBuf;
|
|
zstream.avail_in = compLen;
|
|
zstream.next_out = (Bytef*) writeBuf;
|
|
zstream.avail_out = sizeof(writeBuf);
|
|
zstream.data_type = Z_UNKNOWN;
|
|
|
|
/*
|
|
* Use the undocumented "negative window bits" feature to tell zlib
|
|
* that there's no zlib header waiting for it.
|
|
*/
|
|
zerr = inflateInit2(&zstream, -MAX_WBITS);
|
|
if (zerr != Z_OK) {
|
|
if (zerr == Z_VERSION_ERROR) {
|
|
LOGE("Installed zlib is not compatible with linked version (%s)\n",
|
|
ZLIB_VERSION);
|
|
} else {
|
|
LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
|
|
}
|
|
goto bail;
|
|
}
|
|
|
|
/*
|
|
* Loop while we have more to do.
|
|
*/
|
|
do {
|
|
/*
|
|
* Expand data.
|
|
*/
|
|
zerr = inflate(&zstream, Z_NO_FLUSH);
|
|
if (zerr != Z_OK && zerr != Z_STREAM_END) {
|
|
LOGW("zlib inflate: zerr=%d (nIn=%p aIn=%u nOut=%p aOut=%u)\n",
|
|
zerr, zstream.next_in, zstream.avail_in,
|
|
zstream.next_out, zstream.avail_out);
|
|
goto z_bail;
|
|
}
|
|
|
|
/* write when we're full or when we're done */
|
|
if (zstream.avail_out == 0 ||
|
|
(zerr == Z_STREAM_END && zstream.avail_out != sizeof(writeBuf)))
|
|
{
|
|
long writeSize = zstream.next_out - writeBuf;
|
|
int cc = write(fd, writeBuf, writeSize);
|
|
if (cc != (int) writeSize) {
|
|
LOGW("write failed in inflate (%d vs %ld)\n", cc, writeSize);
|
|
goto z_bail;
|
|
}
|
|
|
|
zstream.next_out = writeBuf;
|
|
zstream.avail_out = sizeof(writeBuf);
|
|
}
|
|
} while (zerr == Z_OK);
|
|
|
|
assert(zerr == Z_STREAM_END); /* other errors should've been caught */
|
|
|
|
/* paranoia */
|
|
if ((long) zstream.total_out != uncompLen) {
|
|
LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
|
|
zstream.total_out, uncompLen);
|
|
goto z_bail;
|
|
}
|
|
|
|
result = true;
|
|
|
|
z_bail:
|
|
inflateEnd(&zstream); /* free up any allocated structures */
|
|
|
|
bail:
|
|
return result;
|
|
}
|