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/*
* Copyright (C) 2013 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.
*/
/*
* Read-only access to Zip archives, with minimal heap allocation.
*/
#ifndef LIBZIPARCHIVE_ZIPARCHIVE_H_
#define LIBZIPARCHIVE_ZIPARCHIVE_H_
#include <stdint.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/types.h>
#include <utils/Compat.h>
__BEGIN_DECLS
/* Zip compression methods we support */
enum {
kCompressStored = 0, // no compression
kCompressDeflated = 8, // standard deflate
};
struct ZipString {
const uint8_t* name;
uint16_t name_length;
ZipString() {}
/*
* entry_name has to be an c-style string with only ASCII characters.
*/
explicit ZipString(const char* entry_name);
bool operator==(const ZipString& rhs) const {
return name && (name_length == rhs.name_length) &&
(memcmp(name, rhs.name, name_length) == 0);
}
bool StartsWith(const ZipString& prefix) const {
return name && (name_length >= prefix.name_length) &&
(memcmp(name, prefix.name, prefix.name_length) == 0);
}
bool EndsWith(const ZipString& suffix) const {
return name && (name_length >= suffix.name_length) &&
(memcmp(name + name_length - suffix.name_length, suffix.name,
suffix.name_length) == 0);
}
};
/*
* Represents information about a zip entry in a zip file.
*/
struct ZipEntry {
// Compression method: One of kCompressStored or
// kCompressDeflated.
uint16_t method;
// Modification time. The zipfile format specifies
// that the first two little endian bytes contain the time
// and the last two little endian bytes contain the date.
uint32_t mod_time;
// 1 if this entry contains a data descriptor segment, 0
// otherwise.
uint8_t has_data_descriptor;
// Crc32 value of this ZipEntry. This information might
// either be stored in the local file header or in a special
// Data descriptor footer at the end of the file entry.
uint32_t crc32;
// Compressed length of this ZipEntry. Might be present
// either in the local file header or in the data descriptor
// footer.
uint32_t compressed_length;
// Uncompressed length of this ZipEntry. Might be present
// either in the local file header or in the data descriptor
// footer.
uint32_t uncompressed_length;
// The offset to the start of data for this ZipEntry.
off64_t offset;
};
typedef void* ZipArchiveHandle;
/*
* Open a Zip archive, and sets handle to the value of the opaque
* handle for the file. This handle must be released by calling
* CloseArchive with this handle.
*
* Returns 0 on success, and negative values on failure.
*/
int32_t OpenArchive(const char* fileName, ZipArchiveHandle* handle);
/*
* Like OpenArchive, but takes a file descriptor open for reading
* at the start of the file. The descriptor must be mappable (this does
* not allow access to a stream).
*
* Sets handle to the value of the opaque handle for this file descriptor.
* This handle must be released by calling CloseArchive with this handle.
*
* If assume_ownership parameter is 'true' calling CloseArchive will close
* the file.
*
* This function maps and scans the central directory and builds a table
* of entries for future lookups.
*
* "debugFileName" will appear in error messages, but is not otherwise used.
*
* Returns 0 on success, and negative values on failure.
*/
int32_t OpenArchiveFd(const int fd, const char* debugFileName,
ZipArchiveHandle *handle, bool assume_ownership = true);
/*
* Close archive, releasing resources associated with it. This will
* unmap the central directory of the zipfile and free all internal
* data structures associated with the file. It is an error to use
* this handle for any further operations without an intervening
* call to one of the OpenArchive variants.
*/
void CloseArchive(ZipArchiveHandle handle);
/*
* Find an entry in the Zip archive, by name. |entryName| must be a null
* terminated string, and |data| must point to a writeable memory location.
*
* Returns 0 if an entry is found, and populates |data| with information
* about this entry. Returns negative values otherwise.
*
* It's important to note that |data->crc32|, |data->compLen| and
* |data->uncompLen| might be set to values from the central directory
* if this file entry contains a data descriptor footer. To verify crc32s
* and length, a call to VerifyCrcAndLengths must be made after entry data
* has been processed.
*
* On non-Windows platforms this method does not modify internal state and
* can be called concurrently.
*/
int32_t FindEntry(const ZipArchiveHandle handle, const ZipString& entryName,
ZipEntry* data);
/*
* Start iterating over all entries of a zip file. The order of iteration
* is not guaranteed to be the same as the order of elements
* in the central directory but is stable for a given zip file. |cookie| will
* contain the value of an opaque cookie which can be used to make one or more
* calls to Next. All calls to StartIteration must be matched by a call to
* EndIteration to free any allocated memory.
*
* This method also accepts optional prefix and suffix to restrict iteration to
* entry names that start with |optional_prefix| or end with |optional_suffix|.
*
* Returns 0 on success and negative values on failure.
*/
int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr,
const ZipString* optional_prefix,
const ZipString* optional_suffix);
/*
* Advance to the next element in the zipfile in iteration order.
*
* Returns 0 on success, -1 if there are no more elements in this
* archive and lower negative values on failure.
*/
int32_t Next(void* cookie, ZipEntry* data, ZipString* name);
/*
* End iteration over all entries of a zip file and frees the memory allocated
* in StartIteration.
*/
void EndIteration(void* cookie);
/*
* Uncompress and write an entry to an open file identified by |fd|.
* |entry->uncompressed_length| bytes will be written to the file at
* its current offset, and the file will be truncated at the end of
* the uncompressed data.
*
* Returns 0 on success and negative values on failure.
*/
int32_t ExtractEntryToFile(ZipArchiveHandle handle, ZipEntry* entry, int fd);
/**
* Uncompress a given zip entry to the memory region at |begin| and of
* size |size|. This size is expected to be the same as the *declared*
* uncompressed length of the zip entry. It is an error if the *actual*
* number of uncompressed bytes differs from this number.
*
* Returns 0 on success and negative values on failure.
*/
int32_t ExtractToMemory(ZipArchiveHandle handle, ZipEntry* entry,
uint8_t* begin, uint32_t size);
int GetFileDescriptor(const ZipArchiveHandle handle);
const char* ErrorCodeString(int32_t error_code);
__END_DECLS
#endif // LIBZIPARCHIVE_ZIPARCHIVE_H_