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99d7e08dff
We now define GenericLexer as a template to allow using it with UTF-16 strings. To keep existing users happy, the template is defined in the Detail namespace. Then AK::GenericLexer is an alias for a char-based view, and AK::Utf16GenericLexer is an alias for a char16-based view.
41 lines
1.5 KiB
C++
41 lines
1.5 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/GenericLexer.h>
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namespace AK {
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LineTrackingLexer::Position LineTrackingLexer::position_for(size_t index) const
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{
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// Sad case: we have no idea where the nearest newline is, so we have to
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// scan ahead a bit.
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while (index > m_largest_known_line_start_position) {
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auto next_newline = m_input.find('\n', m_largest_known_line_start_position);
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if (!next_newline.has_value()) {
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// No more newlines, add the end of the input as a line start to avoid searching again.
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m_line_start_positions->insert(input_length(), m_line_start_positions->size());
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m_largest_known_line_start_position = input_length();
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break;
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}
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m_line_start_positions->insert(next_newline.value() + 1, m_line_start_positions->size());
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m_largest_known_line_start_position = next_newline.value() + 1;
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}
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// We should always have at least the first line start position.
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auto previous_line_it = m_line_start_positions->find_largest_not_above_iterator(index);
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auto previous_line_index = previous_line_it.key();
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auto line = *previous_line_it;
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auto column = index - previous_line_index;
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if (line == 0) {
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// First line, take into account the start position.
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column += m_first_line_start_position.column;
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}
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line += m_first_line_start_position.line;
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return { index, line, column };
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}
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}
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