| /* |
| * Copyright (C) 2022 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS |
| * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| * THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #pragma once |
| |
| #include "Token.h" |
| #include <wtf/ASCIICType.h> |
| #include <wtf/text/StringView.h> |
| #include <wtf/text/WTFString.h> |
| |
| namespace WGSL { |
| |
| template<typename T> |
| class Lexer { |
| public: |
| Lexer(const String& wgsl) |
| { |
| if constexpr (std::is_same<T, LChar>::value) { |
| m_code = wgsl.characters8(); |
| m_codeEnd = m_code + wgsl.sizeInBytes(); |
| } else { |
| static_assert(std::is_same<T, UChar>::value, "The lexer expects its template parameter to be either LChar or UChar"); |
| m_code = wgsl.characters16(); |
| ASSERT(!(wgsl.sizeInBytes() % 2)); |
| m_codeEnd = m_code + wgsl.sizeInBytes() / 2; |
| } |
| |
| m_current = (m_code != m_codeEnd) ? *m_code : 0; |
| } |
| |
| Token lex(); |
| bool isAtEndOfFile() const; |
| SourcePosition currentPosition() const { return m_currentPosition; } |
| |
| private: |
| unsigned currentOffset() const { return m_currentPosition.m_offset; } |
| unsigned currentTokenLength() const { return currentOffset() - m_tokenStartingPosition.m_offset; } |
| |
| Token makeToken(TokenType type) |
| { |
| return { type, m_tokenStartingPosition, currentTokenLength() }; |
| } |
| Token makeLiteralToken(TokenType type, double literalValue) |
| { |
| return { type, m_tokenStartingPosition, currentTokenLength(), literalValue }; |
| } |
| Token makeIdentifierToken(StringView view) |
| { |
| return { WGSL::TokenType::Identifier, m_tokenStartingPosition, currentTokenLength(), view }; |
| } |
| |
| void shift(); |
| T peek(unsigned); |
| void skipWhitespace(); |
| |
| // Reads [0-9]+ |
| std::optional<uint64_t> parseDecimalInteger(); |
| // Parse pattern (e|E)(\+|-)?[0-9]+f? if it is present, and return the exponent |
| std::optional<int64_t> parseDecimalFloatExponent(); |
| // Checks whether there is an "i" or "u" coming, and return the right kind of literal token |
| Token parseIntegerLiteralSuffix(double literalValue); |
| |
| static bool isIdentifierStart(T character) { return isASCIIAlpha(character); } |
| static bool isValidIdentifierCharacter(T character) { return isASCIIAlphanumeric(character) || character == '_'; } |
| static unsigned readDecimal(T character) |
| { |
| ASSERT(isASCIIDigit(character)); |
| return character - '0'; |
| } |
| |
| T m_current; |
| const T* m_code; |
| const T* m_codeEnd; |
| SourcePosition m_currentPosition { 0, 0, 0 }; |
| SourcePosition m_tokenStartingPosition { 0, 0, 0 }; |
| }; |
| |
| } |