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      1 /*
      2  * Copyright (C) 2006 The Android Open Source Project
      3  *
      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
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     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.
     15  */
     16 
     17 //
     18 // Zip archive entries.
     19 //
     20 // The ZipEntry class is tightly meshed with the ZipFile class.
     21 //
     22 #ifndef __LIBS_ZIPENTRY_H
     23 #define __LIBS_ZIPENTRY_H
     24 
     25 #include <utils/Errors.h>
     26 
     27 #include <stdlib.h>
     28 #include <stdio.h>
     29 #include <time.h>
     30 
     31 namespace android {
     32 
     33 class ZipFile;
     34 
     35 /*
     36  * ZipEntry objects represent a single entry in a Zip archive.
     37  *
     38  * You can use one of these to get or set information about an entry, but
     39  * there are no functions here for accessing the data itself.  (We could
     40  * tuck a pointer to the ZipFile in here for convenience, but that raises
     41  * the likelihood of using ZipEntry objects after discarding the ZipFile.)
     42  *
     43  * File information is stored in two places: next to the file data (the Local
     44  * File Header, and possibly a Data Descriptor), and at the end of the file
     45  * (the Central Directory Entry).  The two must be kept in sync.
     46  */
     47 class ZipEntry {
     48 public:
     49     friend class ZipFile;
     50 
     51     ZipEntry(void)
     52         : mDeleted(false), mMarked(false)
     53         {}
     54     ~ZipEntry(void) {}
     55 
     56     /*
     57      * Returns "true" if the data is compressed.
     58      */
     59     bool isCompressed(void) const {
     60         return mCDE.mCompressionMethod != kCompressStored;
     61     }
     62     int getCompressionMethod(void) const { return mCDE.mCompressionMethod; }
     63 
     64     /*
     65      * Return the uncompressed length.
     66      */
     67     off_t getUncompressedLen(void) const { return mCDE.mUncompressedSize; }
     68 
     69     /*
     70      * Return the compressed length.  For uncompressed data, this returns
     71      * the same thing as getUncompresesdLen().
     72      */
     73     off_t getCompressedLen(void) const { return mCDE.mCompressedSize; }
     74 
     75     /*
     76      * Return the offset of the local file header.
     77      */
     78     off_t getLFHOffset(void) const { return mCDE.mLocalHeaderRelOffset; }
     79 
     80     /*
     81      * Return the absolute file offset of the start of the compressed or
     82      * uncompressed data.
     83      */
     84     off_t getFileOffset(void) const {
     85         return mCDE.mLocalHeaderRelOffset +
     86                 LocalFileHeader::kLFHLen +
     87                 mLFH.mFileNameLength +
     88                 mLFH.mExtraFieldLength;
     89     }
     90 
     91     /*
     92      * Return the data CRC.
     93      */
     94     unsigned long getCRC32(void) const { return mCDE.mCRC32; }
     95 
     96     /*
     97      * Return file modification time in UNIX seconds-since-epoch.
     98      */
     99     time_t getModWhen(void) const;
    100 
    101     /*
    102      * Return the archived file name.
    103      */
    104     const char* getFileName(void) const { return (const char*) mCDE.mFileName; }
    105 
    106     /*
    107      * Application-defined "mark".  Can be useful when synchronizing the
    108      * contents of an archive with contents on disk.
    109      */
    110     bool getMarked(void) const { return mMarked; }
    111     void setMarked(bool val) { mMarked = val; }
    112 
    113     /*
    114      * Some basic functions for raw data manipulation.  "LE" means
    115      * Little Endian.
    116      */
    117     static inline unsigned short getShortLE(const unsigned char* buf) {
    118         return buf[0] | (buf[1] << 8);
    119     }
    120     static inline unsigned long getLongLE(const unsigned char* buf) {
    121         return buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
    122     }
    123     static inline void putShortLE(unsigned char* buf, short val) {
    124         buf[0] = (unsigned char) val;
    125         buf[1] = (unsigned char) (val >> 8);
    126     }
    127     static inline void putLongLE(unsigned char* buf, long val) {
    128         buf[0] = (unsigned char) val;
    129         buf[1] = (unsigned char) (val >> 8);
    130         buf[2] = (unsigned char) (val >> 16);
    131         buf[3] = (unsigned char) (val >> 24);
    132     }
    133 
    134     /* defined for Zip archives */
    135     enum {
    136         kCompressStored     = 0,        // no compression
    137         // shrunk           = 1,
    138         // reduced 1        = 2,
    139         // reduced 2        = 3,
    140         // reduced 3        = 4,
    141         // reduced 4        = 5,
    142         // imploded         = 6,
    143         // tokenized        = 7,
    144         kCompressDeflated   = 8,        // standard deflate
    145         // Deflate64        = 9,
    146         // lib imploded     = 10,
    147         // reserved         = 11,
    148         // bzip2            = 12,
    149     };
    150 
    151     /*
    152      * Deletion flag.  If set, the entry will be removed on the next
    153      * call to "flush".
    154      */
    155     bool getDeleted(void) const { return mDeleted; }
    156 
    157 protected:
    158     /*
    159      * Initialize the structure from the file, which is pointing at
    160      * our Central Directory entry.
    161      */
    162     status_t initFromCDE(FILE* fp);
    163 
    164     /*
    165      * Initialize the structure for a new file.  We need the filename
    166      * and comment so that we can properly size the LFH area.  The
    167      * filename is mandatory, the comment is optional.
    168      */
    169     void initNew(const char* fileName, const char* comment);
    170 
    171     /*
    172      * Initialize the structure with the contents of a ZipEntry from
    173      * another file.
    174      */
    175     status_t initFromExternal(const ZipFile* pZipFile, const ZipEntry* pEntry);
    176 
    177     /*
    178      * Add some pad bytes to the LFH.  We do this by adding or resizing
    179      * the "extra" field.
    180      */
    181     status_t addPadding(int padding);
    182 
    183     /*
    184      * Set information about the data for this entry.
    185      */
    186     void setDataInfo(long uncompLen, long compLen, unsigned long crc32,
    187         int compressionMethod);
    188 
    189     /*
    190      * Set the modification date.
    191      */
    192     void setModWhen(time_t when);
    193 
    194     /*
    195      * Set the offset of the local file header, relative to the start of
    196      * the current file.
    197      */
    198     void setLFHOffset(off_t offset) {
    199         mCDE.mLocalHeaderRelOffset = (long) offset;
    200     }
    201 
    202     /* mark for deletion; used by ZipFile::remove() */
    203     void setDeleted(void) { mDeleted = true; }
    204 
    205 private:
    206     /* these are private and not defined */
    207     ZipEntry(const ZipEntry& src);
    208     ZipEntry& operator=(const ZipEntry& src);
    209 
    210     /* returns "true" if the CDE and the LFH agree */
    211     bool compareHeaders(void) const;
    212     void copyCDEtoLFH(void);
    213 
    214     bool        mDeleted;       // set if entry is pending deletion
    215     bool        mMarked;        // app-defined marker
    216 
    217     /*
    218      * Every entry in the Zip archive starts off with one of these.
    219      */
    220     class LocalFileHeader {
    221     public:
    222         LocalFileHeader(void) :
    223             mVersionToExtract(0),
    224             mGPBitFlag(0),
    225             mCompressionMethod(0),
    226             mLastModFileTime(0),
    227             mLastModFileDate(0),
    228             mCRC32(0),
    229             mCompressedSize(0),
    230             mUncompressedSize(0),
    231             mFileNameLength(0),
    232             mExtraFieldLength(0),
    233             mFileName(NULL),
    234             mExtraField(NULL)
    235         {}
    236         virtual ~LocalFileHeader(void) {
    237             delete[] mFileName;
    238             delete[] mExtraField;
    239         }
    240 
    241         status_t read(FILE* fp);
    242         status_t write(FILE* fp);
    243 
    244         // unsigned long mSignature;
    245         unsigned short  mVersionToExtract;
    246         unsigned short  mGPBitFlag;
    247         unsigned short  mCompressionMethod;
    248         unsigned short  mLastModFileTime;
    249         unsigned short  mLastModFileDate;
    250         unsigned long   mCRC32;
    251         unsigned long   mCompressedSize;
    252         unsigned long   mUncompressedSize;
    253         unsigned short  mFileNameLength;
    254         unsigned short  mExtraFieldLength;
    255         unsigned char*  mFileName;
    256         unsigned char*  mExtraField;
    257 
    258         enum {
    259             kSignature      = 0x04034b50,
    260             kLFHLen         = 30,       // LocalFileHdr len, excl. var fields
    261         };
    262 
    263         void dump(void) const;
    264     };
    265 
    266     /*
    267      * Every entry in the Zip archive has one of these in the "central
    268      * directory" at the end of the file.
    269      */
    270     class CentralDirEntry {
    271     public:
    272         CentralDirEntry(void) :
    273             mVersionMadeBy(0),
    274             mVersionToExtract(0),
    275             mGPBitFlag(0),
    276             mCompressionMethod(0),
    277             mLastModFileTime(0),
    278             mLastModFileDate(0),
    279             mCRC32(0),
    280             mCompressedSize(0),
    281             mUncompressedSize(0),
    282             mFileNameLength(0),
    283             mExtraFieldLength(0),
    284             mFileCommentLength(0),
    285             mDiskNumberStart(0),
    286             mInternalAttrs(0),
    287             mExternalAttrs(0),
    288             mLocalHeaderRelOffset(0),
    289             mFileName(NULL),
    290             mExtraField(NULL),
    291             mFileComment(NULL)
    292         {}
    293         virtual ~CentralDirEntry(void) {
    294             delete[] mFileName;
    295             delete[] mExtraField;
    296             delete[] mFileComment;
    297         }
    298 
    299         status_t read(FILE* fp);
    300         status_t write(FILE* fp);
    301 
    302         CentralDirEntry& operator=(const CentralDirEntry& src);
    303 
    304         // unsigned long mSignature;
    305         unsigned short  mVersionMadeBy;
    306         unsigned short  mVersionToExtract;
    307         unsigned short  mGPBitFlag;
    308         unsigned short  mCompressionMethod;
    309         unsigned short  mLastModFileTime;
    310         unsigned short  mLastModFileDate;
    311         unsigned long   mCRC32;
    312         unsigned long   mCompressedSize;
    313         unsigned long   mUncompressedSize;
    314         unsigned short  mFileNameLength;
    315         unsigned short  mExtraFieldLength;
    316         unsigned short  mFileCommentLength;
    317         unsigned short  mDiskNumberStart;
    318         unsigned short  mInternalAttrs;
    319         unsigned long   mExternalAttrs;
    320         unsigned long   mLocalHeaderRelOffset;
    321         unsigned char*  mFileName;
    322         unsigned char*  mExtraField;
    323         unsigned char*  mFileComment;
    324 
    325         void dump(void) const;
    326 
    327         enum {
    328             kSignature      = 0x02014b50,
    329             kCDELen         = 46,       // CentralDirEnt len, excl. var fields
    330         };
    331     };
    332 
    333     enum {
    334         //kDataDescriptorSignature  = 0x08074b50,   // currently unused
    335         kDataDescriptorLen  = 16,           // four 32-bit fields
    336 
    337         kDefaultVersion     = 20,           // need deflate, nothing much else
    338         kDefaultMadeBy      = 0x0317,       // 03=UNIX, 17=spec v2.3
    339         kUsesDataDescr      = 0x0008,       // GPBitFlag bit 3
    340     };
    341 
    342     LocalFileHeader     mLFH;
    343     CentralDirEntry     mCDE;
    344 };
    345 
    346 }; // namespace android
    347 
    348 #endif // __LIBS_ZIPENTRY_H
    349