C++ ZipEntry::getLFHOffset方法代码示例

/*
 * Crunch deleted files out of an archive by shifting the later files down.
 *
 * Because we're not using a temp file, we do the operation inside the
 * current file.
 */
status_t ZipFile::crunchArchive(void)
{
    status_t result = NO_ERROR;
    int i, count;
    long delCount, adjust;

#if 0
    printf("CONTENTS:\n");
    for (i = 0; i < (int) mEntries.size(); i++) {
        printf(" %d: lfhOff=%ld del=%d\n",
            i, mEntries[i]->getLFHOffset(), mEntries[i]->getDeleted());
    }
    printf("  END is %ld\n", (long) mEOCD.mCentralDirOffset);
#endif

    /*
     * Roll through the set of files, shifting them as appropriate.  We
     * could probably get a slight performance improvement by sliding
     * multiple files down at once (because we could use larger reads
     * when operating on batches of small files), but it's not that useful.
     */
    count = mEntries.size();
    delCount = adjust = 0;
    for (i = 0; i < count; i++) {
        ZipEntry* pEntry = mEntries[i];
        long span;

        if (pEntry->getLFHOffset() != 0) {
            long nextOffset;

            /* Get the length of this entry by finding the offset
             * of the next entry.  Directory entries don't have
             * file offsets, so we need to find the next non-directory
             * entry.
             */
            nextOffset = 0;
            for (int ii = i+1; nextOffset == 0 && ii < count; ii++)
                nextOffset = mEntries[ii]->getLFHOffset();
            if (nextOffset == 0)
                nextOffset = mEOCD.mCentralDirOffset;
            span = nextOffset - pEntry->getLFHOffset();

            assert(span >= ZipEntry::LocalFileHeader::kLFHLen);
        } else {
            /* This is a directory entry.  It doesn't have
             * any actual file contents, so there's no need to
             * move anything.
             */
            span = 0;
        }

        //printf("+++ %d: off=%ld span=%ld del=%d [count=%d]\n",
        //    i, pEntry->getLFHOffset(), span, pEntry->getDeleted(), count);

        if (pEntry->getDeleted()) {
            adjust += span;
            delCount++;

            delete pEntry;
            mEntries.removeAt(i);

            /* adjust loop control */
            count--;
            i--;
        } else if (span != 0 && adjust > 0) {
            /* shuffle this entry back */
            //printf("+++ Shuffling '%s' back %ld\n",
            //    pEntry->getFileName(), adjust);
            result = filemove(mZipFp, pEntry->getLFHOffset() - adjust,
                        pEntry->getLFHOffset(), span);
            if (result != NO_ERROR) {
                /* this is why you use a temp file */
                LOGE("error during crunch - archive is toast\n");
                return result;
            }

            pEntry->setLFHOffset(pEntry->getLFHOffset() - adjust);
        }
    }

    /*
     * Fix EOCD info.  We have to wait until the end to do some of this
     * because we use mCentralDirOffset to determine "span" for the
     * last entry.
     */
    mEOCD.mCentralDirOffset -= adjust;
    mEOCD.mNumEntries -= delCount;
    mEOCD.mTotalNumEntries -= delCount;
    mEOCD.mCentralDirSize = 0;  // mark invalid; set by flush()

    assert(mEOCD.mNumEntries == mEOCD.mTotalNumEntries);
    assert(mEOCD.mNumEntries == count);

    return result;
//.........这里部分代码省略.........