Function astcenc_context_alloc

Source/astcenc_entry.cpp:726–859

See header for documentation. */

/* See header for documentation. */
astcenc_error astcenc_context_alloc(
	const astcenc_config* configp,
	unsigned int thread_count,
	astcenc_context** context,
	const astcenc_context* parent_context
) {
	astcenc_error status;

	status = validate_cpu_float();
	if (status != ASTCENC_SUCCESS)
	{
		return status;
	}

	if (thread_count == 0)
	{
		return ASTCENC_ERR_BAD_PARAM;
	}

#if defined(ASTCENC_DIAGNOSTICS)
	// Force single threaded compressor use in diagnostic mode
	if (thread_count != 1)
	{
		return ASTCENC_ERR_BAD_PARAM;
	}
#endif

	// Exactly one of config or parent_context must be set
	bool has_config = configp != nullptr;
	bool has_parent = parent_context != nullptr;
	if (!(has_config ^ has_parent))
	{
		return ASTCENC_ERR_BAD_PARAM;
	}

	if (has_parent)
	{
		configp = &parent_context->context.config;
	}

	const astcenc_config& config = *configp;
	astcenc_context* ctxo = new astcenc_context;
	astcenc_contexti* ctx = &ctxo->context;
	ctx->thread_count = thread_count;
	ctx->config = *configp;
	ctx->working_buffers = nullptr;

	// These are allocated per-compress, as they depend on image size
	ctx->input_alpha_averages = nullptr;

	// Copy the config first and validate the copy (we may modify it)
	status = validate_config(ctx->config);
	if (status != ASTCENC_SUCCESS)
	{
		delete ctxo;
		return status;
	}