Function LoadResourceToBufferWithOffset

engine/resource/src/resource.cpp:587–649

}

Result LoadResourceToBufferWithOffset(HFactory factory, const char* path, const char* original_name, uint32_t offset, uint32_t size, uint32_t* resource_size, uint32_t* buffer_size, LoadBufferType* buffer)
{
    DM_PROFILE(__FUNCTION__);

    char normalized_path[RESOURCE_PATH_MAX];
    GetCanonicalPath(path, normalized_path, sizeof(normalized_path)); // normalize the path

    // Let's find the resource in the current mounts

    dmhash_t normalized_path_hash = dmHashString64(normalized_path);
    // TODO: It might be good to get the HMount for the resource, and use that for both GetResourceSize and ReadResource
    // Otherwise, there's a small chance of a race condition between the two calls. (i.e. a mount gets added or removed)

    uint32_t file_size; // The full size of the resources
    dmResource::Result r = dmResourceMounts::GetResourceSize(factory->m_Mounts, normalized_path_hash, normalized_path, &file_size);
    if (r == dmResource::RESULT_OK)
    {
        *resource_size = file_size;

        uint32_t bytes_to_read = file_size;
        bool is_streaming = false;
        if (size != RESOURCE_INVALID_PRELOAD_SIZE)
        {
            bytes_to_read = dmMath::Min(file_size, size);
            is_streaming = true;
        }

        if (buffer->Capacity() < bytes_to_read) {
            buffer->SetCapacity(bytes_to_read);
        }
        buffer->SetSize(bytes_to_read);

        // Only actually read the resource if we requested any bytes
        uint32_t nread = 0;
        if (bytes_to_read > 0)
        {
            if (is_streaming)
            {
                // no decryption or decompressing is done on these resources
                r = dmResourceMounts::ReadResourcePartial(factory->m_Mounts, normalized_path_hash, normalized_path, offset, bytes_to_read, (uint8_t*)buffer->Begin(), &nread);
            }
            else
            {
                // The non streaming code path supports unpacking compressed resources
                r = dmResourceMounts::ReadResource(factory->m_Mounts, normalized_path_hash, normalized_path, (uint8_t*)buffer->Begin(), buffer->Size());
                nread = buffer->Size();
            }
        }

        if (r == dmResource::RESULT_OK)
        {
            buffer->SetSize(nread); // If we read fewer bytes than previously set
            *buffer_size = nread;
            return RESULT_OK;
        }
        else
        {
            buffer->SetSize(0);