mirror of
https://github.com/SerenityOS/serenity
synced 2024-07-21 01:55:07 +00:00
254e010c75
Problem: - Much of the `GenericLexer` can be `constexpr`, but is not. Solution: - Make it `constexpr` and de-duplicate code. - Extend some of `StringView` with `constexpr` to support. - Add tests to ensure `constexpr` behavior. Note: - Construction of `StringView` from pointer and length is not `constexpr`-compatible at the moment because the VERIFY cannot be, yet.
132 lines
3.1 KiB
C++
132 lines
3.1 KiB
C++
/*
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* Copyright (c) 2020, Benoit Lormeau <blormeau@outlook.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Assertions.h>
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#include <AK/GenericLexer.h>
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#include <AK/String.h>
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#include <AK/StringBuilder.h>
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namespace AK {
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// Consume a number of characters
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StringView GenericLexer::consume(size_t count)
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{
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if (count == 0)
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return {};
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size_t start = m_index;
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size_t length = min(count, m_input.length() - m_index);
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m_index += length;
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return m_input.substring_view(start, length);
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}
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// Consume the rest of the input
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StringView GenericLexer::consume_all()
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{
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if (is_eof())
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return {};
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auto rest = m_input.substring_view(m_index, m_input.length() - m_index);
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m_index = m_input.length();
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return rest;
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}
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// Consume until a new line is found
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StringView GenericLexer::consume_line()
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{
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size_t start = m_index;
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while (!is_eof() && peek() != '\r' && peek() != '\n')
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m_index++;
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size_t length = m_index - start;
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consume_specific('\r');
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consume_specific('\n');
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if (length == 0)
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return {};
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return m_input.substring_view(start, length);
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}
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// Consume and return characters until `stop` is peek'd
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// The `stop` character is ignored, as it is user-defined
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StringView GenericLexer::consume_until(char stop)
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{
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size_t start = m_index;
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while (!is_eof() && peek() != stop)
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m_index++;
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size_t length = m_index - start;
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ignore();
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if (length == 0)
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return {};
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return m_input.substring_view(start, length);
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}
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// Consume and return characters until the string `stop` is found
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// The `stop` string is ignored, as it is user-defined
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StringView GenericLexer::consume_until(const char* stop)
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{
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size_t start = m_index;
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while (!is_eof() && !next_is(stop))
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m_index++;
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size_t length = m_index - start;
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ignore(__builtin_strlen(stop));
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if (length == 0)
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return {};
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return m_input.substring_view(start, length);
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}
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/*
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* Consume a string surrounded by single or double quotes. The returned
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* StringView does not include the quotes. An escape character can be provided
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* to capture the enclosing quotes. Please note that the escape character will
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* still be in the resulting StringView
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*/
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StringView GenericLexer::consume_quoted_string(char escape_char)
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{
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if (!next_is(is_quote))
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return {};
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char quote_char = consume();
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size_t start = m_index;
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while (!is_eof()) {
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if (next_is(escape_char))
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m_index++;
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else if (next_is(quote_char))
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break;
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m_index++;
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}
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size_t length = m_index - start;
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if (peek() != quote_char) {
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// Restore the index in case the string is unterminated
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m_index = start - 1;
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return {};
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}
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// Ignore closing quote
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ignore();
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return m_input.substring_view(start, length);
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}
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String GenericLexer::consume_and_unescape_string(char escape_char)
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{
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auto view = consume_quoted_string(escape_char);
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if (view.is_null())
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return {};
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StringBuilder builder;
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for (size_t i = 0; i < view.length(); ++i)
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builder.append(consume_escaped_character(escape_char));
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return builder.to_string();
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}
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}
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