/*
 * SPIRVSupport.cpp
 *
 * Copyright (c) 2014-2019 The Brenwill Workshop Ltd. (http://www.brenwill.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "SPIRVSupport.h"
#include <spirv/1.0/spirv.h>
#include <spirv-tools/libspirv.h>
#import <CoreFoundation/CFByteOrder.h>

using namespace mvk;
using namespace std;

void mvk::logSPIRV(vector<uint32_t>& spirv, string& spvLog) {
	if ( !((spirv.size() > 4) &&
		   (spirv[0] == SpvMagicNumber) &&
		   (spirv[4] == 0)) ) { return; }

	uint32_t options = (SPV_BINARY_TO_TEXT_OPTION_INDENT);
	spv_text text;
	spv_diagnostic diagnostic = nullptr;
	spv_context context = spvContextCreate(SPV_ENV_VULKAN_1_0);
	spv_result_t error = spvBinaryToText(context, spirv.data(), spirv.size(), options, &text, &diagnostic);
	spvContextDestroy(context);
	if (error) {
		spvDiagnosticPrint(diagnostic);
		spvDiagnosticDestroy(diagnostic);
		return;
	}
	spvLog.append(text->str, text->length);
	spvTextDestroy(text);
}

void mvk::spirvToBytes(const vector<uint32_t>& spv, vector<char>& bytes) {
	// Assumes desired endianness.
	size_t byteCnt = spv.size() * sizeof(uint32_t);
	char* cBytes = (char*)spv.data();
	bytes.clear();
	bytes.insert(bytes.end(), cBytes, cBytes + byteCnt);
}

void mvk::bytesToSPIRV(const vector<char>& bytes, vector<uint32_t>& spv) {
	size_t spvCnt = bytes.size() / sizeof(uint32_t);
	uint32_t* cSPV = (uint32_t*)bytes.data();
	spv.clear();
	spv.insert(spv.end(), cSPV, cSPV + spvCnt);
	ensureSPIRVEndianness(spv);
}

bool mvk::ensureSPIRVEndianness(vector<uint32_t>& spv) {
	if (spv.empty()) { return false; }					// Nothing to convert

	uint32_t magNum = spv.front();
	if (magNum == SpvMagicNumber) { return false; }	// No need to convert

	if (CFSwapInt32(magNum) == SpvMagicNumber) {		// Yep, it's SPIR-V, but wrong endianness
		for (auto& elem : spv) { elem = CFSwapInt32(elem); }
		return true;
	}
	return false;		// Not SPIR-V, so don't convert
}