mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-12-25 01:01:04 +00:00
78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
// Copyright (c) 2015-2016 The Khronos Group Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "spirv_endian.h"
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#include <cstring>
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enum {
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I32_ENDIAN_LITTLE = 0x03020100ul,
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I32_ENDIAN_BIG = 0x00010203ul,
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};
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// This constant value allows the detection of the host machine's endianness.
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// Accessing it through the "value" member is valid due to C++11 section 3.10
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// paragraph 10.
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static const union {
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unsigned char bytes[4];
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uint32_t value;
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} o32_host_order = {{0, 1, 2, 3}};
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#define I32_ENDIAN_HOST (o32_host_order.value)
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uint32_t spvFixWord(const uint32_t word, const spv_endianness_t endian) {
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if ((SPV_ENDIANNESS_LITTLE == endian && I32_ENDIAN_HOST == I32_ENDIAN_BIG) ||
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(SPV_ENDIANNESS_BIG == endian && I32_ENDIAN_HOST == I32_ENDIAN_LITTLE)) {
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return (word & 0x000000ff) << 24 | (word & 0x0000ff00) << 8 |
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(word & 0x00ff0000) >> 8 | (word & 0xff000000) >> 24;
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}
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return word;
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}
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uint64_t spvFixDoubleWord(const uint32_t low, const uint32_t high,
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const spv_endianness_t endian) {
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return (uint64_t(spvFixWord(high, endian)) << 32) | spvFixWord(low, endian);
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}
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spv_result_t spvBinaryEndianness(spv_const_binary binary,
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spv_endianness_t* pEndian) {
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if (!binary->code || !binary->wordCount) return SPV_ERROR_INVALID_BINARY;
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if (!pEndian) return SPV_ERROR_INVALID_POINTER;
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uint8_t bytes[4];
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memcpy(bytes, binary->code, sizeof(uint32_t));
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if (0x03 == bytes[0] && 0x02 == bytes[1] && 0x23 == bytes[2] &&
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0x07 == bytes[3]) {
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*pEndian = SPV_ENDIANNESS_LITTLE;
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return SPV_SUCCESS;
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}
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if (0x07 == bytes[0] && 0x23 == bytes[1] && 0x02 == bytes[2] &&
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0x03 == bytes[3]) {
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*pEndian = SPV_ENDIANNESS_BIG;
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return SPV_SUCCESS;
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}
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return SPV_ERROR_INVALID_BINARY;
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}
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bool spvIsHostEndian(spv_endianness_t endian) {
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return ((SPV_ENDIANNESS_LITTLE == endian) &&
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(I32_ENDIAN_LITTLE == I32_ENDIAN_HOST)) ||
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((SPV_ENDIANNESS_BIG == endian) &&
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(I32_ENDIAN_BIG == I32_ENDIAN_HOST));
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}
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