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// Copyright (c) 2015-2016 The Khronos Group Inc.
//
// 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 "source/spirv_endian.h"
#include <cstring>
enum {
I32_ENDIAN_LITTLE = 0x03020100ul,
I32_ENDIAN_BIG = 0x00010203ul,
};
// This constant value allows the detection of the host machine's endianness.
// Accessing it through the "value" member is valid due to C++11 section 3.10
// paragraph 10.
static const union {
unsigned char bytes[4];
uint32_t value;
} o32_host_order = {{0, 1, 2, 3}};
#define I32_ENDIAN_HOST (o32_host_order.value)
uint32_t spvFixWord(const uint32_t word, const spv_endianness_t endian) {
if ((SPV_ENDIANNESS_LITTLE == endian && I32_ENDIAN_HOST == I32_ENDIAN_BIG) ||
(SPV_ENDIANNESS_BIG == endian && I32_ENDIAN_HOST == I32_ENDIAN_LITTLE)) {
return (word & 0x000000ff) << 24 | (word & 0x0000ff00) << 8 |
(word & 0x00ff0000) >> 8 | (word & 0xff000000) >> 24;
}
return word;
}
uint64_t spvFixDoubleWord(const uint32_t low, const uint32_t high,
const spv_endianness_t endian) {
return (uint64_t(spvFixWord(high, endian)) << 32) | spvFixWord(low, endian);
}
spv_result_t spvBinaryEndianness(spv_const_binary binary,
spv_endianness_t* pEndian) {
if (!binary->code || !binary->wordCount) return SPV_ERROR_INVALID_BINARY;
if (!pEndian) return SPV_ERROR_INVALID_POINTER;
uint8_t bytes[4];
memcpy(bytes, binary->code, sizeof(uint32_t));
if (0x03 == bytes[0] && 0x02 == bytes[1] && 0x23 == bytes[2] &&
0x07 == bytes[3]) {
*pEndian = SPV_ENDIANNESS_LITTLE;
return SPV_SUCCESS;
}
if (0x07 == bytes[0] && 0x23 == bytes[1] && 0x02 == bytes[2] &&
0x03 == bytes[3]) {
*pEndian = SPV_ENDIANNESS_BIG;
return SPV_SUCCESS;
}
return SPV_ERROR_INVALID_BINARY;
}
bool spvIsHostEndian(spv_endianness_t endian) {
return ((SPV_ENDIANNESS_LITTLE == endian) &&
(I32_ENDIAN_LITTLE == I32_ENDIAN_HOST)) ||
((SPV_ENDIANNESS_BIG == endian) &&
(I32_ENDIAN_BIG == I32_ENDIAN_HOST));
}
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