Function FindEntry

Bcore/src/main/cpp/ziparchive/zip_archive.cc:492–642

}

static int32_t FindEntry(const ZipArchive* archive, const int ent, ZipEntry* data) {
  const uint16_t nameLen = archive->hash_table[ent].name_length;

  // Recover the start of the central directory entry from the filename
  // pointer.  The filename is the first entry past the fixed-size data,
  // so we can just subtract back from that.
  const uint8_t* ptr = archive->hash_table[ent].name;
  ptr -= sizeof(CentralDirectoryRecord);

  // This is the base of our mmapped region, we have to sanity check that
  // the name that's in the hash table is a pointer to a location within
  // this mapped region.
  const uint8_t* base_ptr = archive->central_directory.GetBasePtr();
  if (ptr < base_ptr || ptr > base_ptr + archive->central_directory.GetMapLength()) {
    //chensenhuaALOGW("Zip: Invalid entry pointer");
    return kInvalidOffset;
  }

  const CentralDirectoryRecord* cdr = reinterpret_cast<const CentralDirectoryRecord*>(ptr);

  // The offset of the start of the central directory in the zipfile.
  // We keep this lying around so that we can sanity check all our lengths
  // and our per-file structures.
  const off64_t cd_offset = archive->directory_offset;

  // Fill out the compression method, modification time, crc32
  // and other interesting attributes from the central directory. These
  // will later be compared against values from the local file header.
  data->method = cdr->compression_method;
  data->mod_time = cdr->last_mod_date << 16 | cdr->last_mod_time;
  data->crc32 = cdr->crc32;
  data->compressed_length = cdr->compressed_size;
  data->uncompressed_length = cdr->uncompressed_size;

  // Figure out the local header offset from the central directory. The
  // actual file data will begin after the local header and the name /
  // extra comments.
  const off64_t local_header_offset = cdr->local_file_header_offset;
  if (local_header_offset + static_cast<off64_t>(sizeof(LocalFileHeader)) >= cd_offset) {
    //chensenhuaALOGW("Zip: bad local hdr offset in zip");
    return kInvalidOffset;
  }

  uint8_t lfh_buf[sizeof(LocalFileHeader)];
  if (!archive->mapped_zip.ReadAtOffset(lfh_buf, sizeof(lfh_buf), local_header_offset)) {
    //chensenhua ALOGW("Zip: failed reading lfh name from offset %" PRId64,
    //chensenhua    static_cast<int64_t>(local_header_offset));
    return kIoError;
  }

  const LocalFileHeader* lfh = reinterpret_cast<const LocalFileHeader*>(lfh_buf);

  if (lfh->lfh_signature != LocalFileHeader::kSignature) {
    //chensenhua ALOGW("Zip: didn't find signature at start of lfh, offset=%" PRId64,
    //chensenhua     static_cast<int64_t>(local_header_offset));
    return kInvalidOffset;
  }