108 lines
3.0 KiB
C++
108 lines
3.0 KiB
C++
// Scintilla source code edit control
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/** @file SparseState.h
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** Hold lexer state that may change rarely.
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** This is often per-line state such as whether a particular type of section has been entered.
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** A state continues until it is changed.
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**/
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// Copyright 2011 by Neil Hodgson <neilh@scintilla.org>
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// The License.txt file describes the conditions under which this software may be distributed.
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#ifndef SPARSESTATE_H
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#define SPARSESTATE_H
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namespace Lexilla {
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template <typename T>
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class SparseState {
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struct State {
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Sci_Position position;
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T value;
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constexpr State(Sci_Position position_, T value_) noexcept :
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position(position_), value(std::move(value_)) {
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}
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inline bool operator<(const State &other) const noexcept {
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return position < other.position;
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}
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inline bool operator==(const State &other) const noexcept {
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return (position == other.position) && (value == other.value);
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}
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};
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Sci_Position positionFirst;
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typedef std::vector<State> stateVector;
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stateVector states;
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typename stateVector::iterator Find(Sci_Position position) {
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const State searchValue(position, T());
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return std::lower_bound(states.begin(), states.end(), searchValue);
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}
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public:
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explicit SparseState(Sci_Position positionFirst_=-1) {
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positionFirst = positionFirst_;
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}
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void Set(Sci_Position position, T value) {
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Delete(position);
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if (states.empty() || (value != states[states.size()-1].value)) {
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states.push_back(State(position, value));
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}
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}
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T ValueAt(Sci_Position position) {
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if (states.empty())
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return T();
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if (position < states[0].position)
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return T();
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typename stateVector::iterator low = Find(position);
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if (low == states.end()) {
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return states[states.size()-1].value;
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} else {
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if (low->position > position) {
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--low;
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}
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return low->value;
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}
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}
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bool Delete(Sci_Position position) {
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typename stateVector::iterator low = Find(position);
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if (low != states.end()) {
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states.erase(low, states.end());
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return true;
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}
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return false;
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}
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size_t size() const {
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return states.size();
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}
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// Returns true if Merge caused a significant change
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bool Merge(const SparseState<T> &other, Sci_Position ignoreAfter) {
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// Changes caused beyond ignoreAfter are not significant
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Delete(ignoreAfter+1);
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bool different = true;
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bool changed = false;
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typename stateVector::iterator low = Find(other.positionFirst);
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if (static_cast<size_t>(states.end() - low) == other.states.size()) {
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// Same number in other as after positionFirst in this
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different = !std::equal(low, states.end(), other.states.begin());
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}
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if (different) {
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if (low != states.end()) {
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states.erase(low, states.end());
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changed = true;
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}
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typename stateVector::const_iterator startOther = other.states.begin();
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if (!states.empty() && !other.states.empty() && states.back().value == startOther->value)
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++startOther;
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if (startOther != other.states.end()) {
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states.insert(states.end(), startOther, other.states.end());
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changed = true;
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}
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}
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return changed;
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}
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};
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}
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#endif
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