2 * Copyright (C) 2008 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * Read-only access to Zip archives, with minimal heap allocation.
20 #ifndef LIBDEX_ZIPARCHIVE_H_
21 #define LIBDEX_ZIPARCHIVE_H_
24 #include "DexFile.h" // need DEX_INLINE
27 * Trivial typedef to ensure that ZipEntry is not treated as a simple
28 * integer. We use NULL to indicate an invalid value.
30 typedef void* ZipEntry;
33 * One entry in the hash table.
37 unsigned short nameLen;
41 * Read-only Zip archive.
43 * We want "open" and "find entry by name" to be fast operations, and
44 * we want to use as little memory as possible. We memory-map the zip
45 * central directory, and load a hash table with pointers to the filenames
46 * (which aren't null-terminated). The other fields are at a fixed offset
47 * from the filename, so we don't need to extract those (but we do need
48 * to byte-read and endian-swap them every time we want them).
50 * It's possible that somebody has handed us a massive (~1GB) zip archive,
51 * so we can't expect to mmap the entire file.
53 * To speed comparisons when doing a lookup by name, we could make the mapping
54 * "private" (copy-on-write) and null-terminate the filenames after verifying
55 * the record structure. However, this requires a private mapping of
56 * every page that the Central Directory touches. Easier to tuck a copy
57 * of the string length into the hash table entry.
60 /* open Zip archive */
63 /* mapped central directory area */
64 off_t mDirectoryOffset;
65 MemMapping mDirectoryMap;
67 /* number of entries in the Zip archive */
71 * We know how many entries are in the Zip archive, so we can have a
72 * fixed-size hash table. We probe on collisions.
75 ZipHashEntry* mHashTable;
78 /* Zip compression methods we support */
80 kCompressStored = 0, // no compression
81 kCompressDeflated = 8, // standard deflate
88 * On success, returns 0 and populates "pArchive". Returns nonzero errno
91 int dexZipOpenArchive(const char* fileName, ZipArchive* pArchive);
94 * Like dexZipOpenArchive, but takes a file descriptor open for reading
95 * at the start of the file. The descriptor must be mappable (this does
96 * not allow access to a stream).
98 * "debugFileName" will appear in error messages, but is not otherwise used.
100 int dexZipPrepArchive(int fd, const char* debugFileName, ZipArchive* pArchive);
103 * Close archive, releasing resources associated with it.
105 * Depending on the implementation this could unmap pages used by classes
106 * stored in a Jar. This should only be done after unloading classes.
108 void dexZipCloseArchive(ZipArchive* pArchive);
111 * Return the archive's file descriptor.
113 DEX_INLINE int dexZipGetArchiveFd(const ZipArchive* pArchive) {
114 return pArchive->mFd;
118 * Find an entry in the Zip archive, by name. Returns NULL if the entry
121 ZipEntry dexZipFindEntry(const ZipArchive* pArchive,
122 const char* entryName);
125 * Retrieve one or more of the "interesting" fields. Non-NULL pointers
128 * Returns 0 on success.
130 int dexZipGetEntryInfo(const ZipArchive* pArchive, ZipEntry entry,
131 int* pMethod, size_t* pUncompLen, size_t* pCompLen, off_t* pOffset,
132 long* pModWhen, long* pCrc32);
137 DEX_INLINE long dexGetZipEntryOffset(const ZipArchive* pArchive,
138 const ZipEntry entry)
141 dexZipGetEntryInfo(pArchive, entry, NULL, NULL, NULL, &val, NULL, NULL);
144 DEX_INLINE size_t dexGetZipEntryUncompLen(const ZipArchive* pArchive,
145 const ZipEntry entry)
148 dexZipGetEntryInfo(pArchive, entry, NULL, &val, NULL, NULL, NULL, NULL);
151 DEX_INLINE long dexGetZipEntryModTime(const ZipArchive* pArchive,
152 const ZipEntry entry)
155 dexZipGetEntryInfo(pArchive, entry, NULL, NULL, NULL, NULL, &val, NULL);
158 DEX_INLINE long dexGetZipEntryCrc32(const ZipArchive* pArchive,
159 const ZipEntry entry)
162 dexZipGetEntryInfo(pArchive, entry, NULL, NULL, NULL, NULL, NULL, &val);
167 * Uncompress and write an entry to a file descriptor.
169 * Returns 0 on success.
171 int dexZipExtractEntryToFile(const ZipArchive* pArchive,
172 const ZipEntry entry, int fd);
175 * Utility function to compute a CRC-32.
177 u4 dexInitCrc32(void);
178 u4 dexComputeCrc32(u4 crc, const void* buf, size_t len);
180 #endif // LIBDEX_ZIPARCHIVE_H_