Method writeMetadata

openvdb/openvdb/points/AttributeArray.h:1730–1785

template<typename ValueType_, typename Codec_>
void
TypedAttributeArray<ValueType_, Codec_>::writeMetadata(std::ostream& os, bool outputTransient, bool paged) const
{
    if (!outputTransient && this->isTransient())    return;

    if (mFlags & PARTIALREAD) {
        OPENVDB_THROW(IoError, "Cannot write out a partially-read AttributeArray.");
    }

    uint8_t flags(mFlags);
    uint8_t serializationFlags(0);
    Index size(mSize);
    Index strideOrTotalSize(mStrideOrTotalSize);
    bool strideOfOne(this->stride() == 1);

    bool bloscCompression = io::getDataCompression(os) & io::COMPRESS_BLOSC;

    // any compressed data needs to be loaded if out-of-core
    if (bloscCompression)    this->doLoad();

    size_t compressedBytes = 0;

    if (!strideOfOne)
    {
        serializationFlags |= WRITESTRIDED;
    }

    if (mIsUniform)
    {
        serializationFlags |= WRITEUNIFORM;
        if (bloscCompression && paged)      serializationFlags |= WRITEPAGED;
    }
    else if (bloscCompression)
    {
        if (paged)      serializationFlags |= WRITEPAGED;
        else {
            const char* charBuffer = reinterpret_cast<const char*>(this->data());
            const size_t inBytes = this->arrayMemUsage();
            compressedBytes = compression::bloscCompressedSize(charBuffer, inBytes);
        }
    }

    Index64 bytes = /*flags*/ sizeof(Int16) + /*size*/ sizeof(Index);

    bytes += (compressedBytes > 0) ? compressedBytes : this->arrayMemUsage();

    // write data

    os.write(reinterpret_cast<const char*>(&bytes), sizeof(Index64));
    os.write(reinterpret_cast<const char*>(&flags), sizeof(uint8_t));
    os.write(reinterpret_cast<const char*>(&serializationFlags), sizeof(uint8_t));
    os.write(reinterpret_cast<const char*>(&size), sizeof(Index));

    // write strided
    if (!strideOfOne) os.write(reinterpret_cast<const char*>(&strideOrTotalSize), sizeof(Index));
}