mirror of
https://github.com/corda/corda.git
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534 lines
15 KiB
Java
534 lines
15 KiB
Java
/* Copyright (c) 2008-2013, Avian Contributors
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Permission to use, copy, modify, and/or distribute this software
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for any purpose with or without fee is hereby granted, provided
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that the above copyright notice and this permission notice appear
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in all copies.
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There is NO WARRANTY for this software. See license.txt for
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details. */
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package java.util.regex;
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import java.util.ArrayList;
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import java.util.Stack;
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/**
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* Compiles regular expressions into {@link PikeVM}s.
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*
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* @author Johannes Schindelin
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*/
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class Compiler implements PikeVMOpcodes {
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private final static CharacterMatcher regularCharacter =
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CharacterMatcher.parse("[^\\\\.*+?|\\[\\]{}()^$]");
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private static class Output {
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private int[] program;
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private int offset;
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private int groupCount = -1;
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private int findPreambleSize;
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private ArrayList<CharacterMatcher> classes;
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private ArrayList<PikeVM> lookarounds;
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public Output(Expression expr) {
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// try-run to determine the code size
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expr.writeCode(this);
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program = new int[offset];
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offset = 0;
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groupCount = -1;
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classes = new ArrayList<CharacterMatcher>();
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lookarounds = new ArrayList<PikeVM>();
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// write it out!
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expr.writeCode(this);
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}
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public void add(int opcode) {
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if (program != null) {
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program[offset] = opcode;
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}
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offset++;
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}
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public int markJump() {
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return offset++;
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}
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public void setJump(int mark) {
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if (program != null) {
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program[mark] = offset;
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}
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}
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public void markFindPreambleEnd() {
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findPreambleSize = offset;
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}
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public PikeVM toVM() {
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CharacterMatcher[] classes = new CharacterMatcher[this.classes.size()];
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this.classes.toArray(classes);
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PikeVM[] lookarounds = new PikeVM[this.lookarounds.size()];
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this.lookarounds.toArray(lookarounds);
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return new PikeVM(program, findPreambleSize, groupCount, classes,
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lookarounds);
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}
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public int addClass(CharacterMatcher characterClass) {
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if (program == null) {
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return -1;
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}
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int result = classes.size();
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classes.add(characterClass);
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return result;
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}
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public int addLookaround(PikeVM lookaround) {
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if (program == null) {
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return -1;
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}
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int result = lookarounds.size();
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lookarounds.add(lookaround);
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return result;
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}
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}
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private abstract class Expression {
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protected abstract void writeCode(Output output);
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}
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private class CharacterRange extends Expression {
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private final CharacterMatcher characterClass;
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public CharacterRange(CharacterMatcher characterClass) {
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this.characterClass = characterClass;
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}
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protected void writeCode(Output output) {
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output.add(CHARACTER_CLASS);
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output.add(output.addClass(characterClass));
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}
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public String toString() {
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return characterClass.toString();
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}
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}
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private class Repeat extends Expression {
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private Expression expr;
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private int minCount, maxCount;
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private boolean greedy;
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public Repeat(Expression expr, int minCount, int maxCount, boolean greedy) {
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if (minCount < 0) {
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throw new RuntimeException("Unexpected min count: " + minCount);
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}
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if (maxCount != -1) {
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if (maxCount == 0) {
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throw new RuntimeException("Unexpected max count: " + maxCount);
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}
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if (minCount > maxCount) {
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throw new RuntimeException("Unexpected range: " + minCount + ", " + maxCount);
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}
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}
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this.expr = expr;
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this.minCount = minCount;
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this.maxCount = maxCount;
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this.greedy = greedy;
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}
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protected void writeCode(Output output) {
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int start = output.offset;
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int splitJmp = greedy ? SPLIT_JMP : SPLIT;
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int split = greedy ? SPLIT : SPLIT_JMP;
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for (int i = 1; i < minCount; ++ i) {
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expr.writeCode(output);
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}
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if (maxCount == -1) {
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if (minCount > 0) {
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int jump = output.offset;
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expr.writeCode(output);
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output.add(splitJmp);
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output.add(jump);
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} else {
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output.add(split);
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int jump = output.markJump();
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expr.writeCode(output);
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output.add(splitJmp);
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output.add(start + 2);
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output.setJump(jump);
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}
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} else {
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if (minCount > 0) {
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expr.writeCode(output);
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}
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if (maxCount > minCount) {
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int[] jumps = new int[maxCount - minCount];
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for (int i = 0; i < jumps.length; ++ i) {
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output.add(split);
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jumps[i] = output.markJump();
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expr.writeCode(output);
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}
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for (int jump : jumps) {
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output.setJump(jump);
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}
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}
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}
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}
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public String toString() {
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String qualifier = greedy ? "" : "?";
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if (minCount == 0 && maxCount < 2) {
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return expr.toString() + (minCount < 0 ? "*" : "?") + qualifier;
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}
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if (minCount == 1 && maxCount < 0) {
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return expr.toString() + "+" + qualifier;
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}
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return expr.toString() + "{" + minCount + ","
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+ (maxCount < 0 ? "" : "" + maxCount) + "}" + qualifier;
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}
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}
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private class Group extends Expression {
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private final boolean capturing;
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private ArrayList<Expression> list = new ArrayList<Expression>();
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private ArrayList<Group> alternatives;
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public Group(boolean capturing, ArrayList<Expression> initialList) {
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this.capturing = capturing;
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if (initialList != null) {
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list.addAll(initialList);
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}
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}
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public void push(Expression expr) {
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list.add(expr);
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}
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public void push(final int c) {
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push(new Expression() {
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public void writeCode(Output output) {
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output.add(c);
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}
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public String toString() {
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if (c >= 0) {
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return "" + (char)c;
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}
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switch (c) {
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case DOT:
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return ".";
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case WORD_BOUNDARY:
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return "\\b";
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case NON_WORD_BOUNDARY:
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return "\\B";
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case LINE_START:
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return "^";
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case LINE_END:
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return "$";
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default:
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throw new RuntimeException("Unhandled opcode: " + c);
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}
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}
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});
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}
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public void startAlternative() {
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if (alternatives == null) {
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alternatives = new ArrayList<Group>();
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}
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alternatives.add(new Group(false, list));
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list.clear();
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}
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public Expression pop() {
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Expression result = list.remove(list.size() - 1);
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return result;
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}
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protected void writeCode(Output output) {
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int groupIndex = -1;
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if (capturing) {
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groupIndex = ++ output.groupCount;
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output.add(SAVE_OFFSET);
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output.add(2 * groupIndex);
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}
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int[] jumps = null;
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if (alternatives != null) {
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jumps = new int[alternatives.size()];
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int i = 0;
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for (Group alternative : alternatives) {
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output.add(SPLIT);
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int jump = output.markJump();
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alternative.writeCode(output);
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output.add(JMP);
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jumps[i++] = output.markJump();
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output.setJump(jump);
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}
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}
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for (Expression expr : list) {
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expr.writeCode(output);
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}
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if (jumps != null) {
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for (int jump : jumps) {
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output.setJump(jump);
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}
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}
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if (capturing) {
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output.add(SAVE_OFFSET);
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output.add(2 * groupIndex + 1);
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}
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}
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public String toString() {
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StringBuilder builder = new StringBuilder();
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if (alternatives != null || list.size() > 1) {
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builder.append('(');
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if (!capturing) {
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builder.append("?:");
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}
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}
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if (alternatives != null) {
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for (Group alternative : alternatives) {
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builder.append(alternative).append('|');
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}
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}
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for (Expression expr : list) {
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builder.append(expr);
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}
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if (alternatives != null || list.size() > 1) {
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builder.append(')');
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}
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return builder.toString();
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}
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}
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private class Lookaround extends Expression {
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private final Group group = new Group(false, null);
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private final boolean forward, negative;
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public Lookaround(boolean forward, boolean negative) {
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this.forward = forward;
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this.negative = negative;
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}
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@Override
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protected void writeCode(Output output) {
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PikeVM vm = new Output(group).toVM();
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if (!forward) {
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vm.reverse();
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}
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output.add(forward ?
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(negative ? NEGATIVE_LOOKAHEAD : LOOKAHEAD) :
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(negative ? NEGATIVE_LOOKAHEAD : LOOKBEHIND));
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output.add(output.addLookaround(vm));
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}
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public String toString() {
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String inner = group.toString();
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if (inner.startsWith("(?:")) {
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inner = inner.substring(3);
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} else {
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inner += ")";
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}
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return "(?=" + inner;
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}
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}
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private class Group0 extends Expression {
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private final Group group;
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public Group0() {
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group = new Group(true, null);
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}
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public void writeCode(Output output) {
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// find() preamble
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int start = output.offset;
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output.add(SPLIT_JMP);
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output.add(start + 5);
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output.add(DOTALL);
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output.add(SPLIT);
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output.add(start + 2);
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output.markFindPreambleEnd();
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group.writeCode(output);
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}
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public String toString() {
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String inner = group.toString();
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return inner.startsWith("(?:") && inner.endsWith(")") ?
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inner.substring(1, inner.length() - 1) : inner;
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}
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}
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private Group0 root;
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private Stack<Group> groups;
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public Compiler() {
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root = new Group0();
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groups = new Stack<Group>();
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groups.add(root.group);
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}
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public Pattern compile(String regex) {
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char[] array = regex.toCharArray();
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CharacterMatcher.Parser characterClassParser =
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new CharacterMatcher.Parser(array);
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for (int index = 0; index < array.length; ++ index) {
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char c = array[index];
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Group current = groups.peek();
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if (regularCharacter.matches(c)) {
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current.push(c);
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continue;
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}
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switch (c) {
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case '.':
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current.push(DOT);
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continue;
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case '\\':
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int unescaped = characterClassParser.parseEscapedCharacter(index + 1);
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if (unescaped >= 0) {
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index = characterClassParser.getEndOffset() - 1;
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current.push((char)unescaped);
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continue;
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}
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CharacterMatcher characterClass = characterClassParser.parseClass(index);
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if (characterClass != null) {
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index = characterClassParser.getEndOffset() - 1;
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current.push(new CharacterRange(characterClass));
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continue;
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}
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switch (array[index + 1]) {
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case 'b':
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index++;
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current.push(WORD_BOUNDARY);
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continue;
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case 'B':
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index++;
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current.push(NON_WORD_BOUNDARY);
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continue;
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}
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throw new RuntimeException("Parse error @" + index + ": " + regex);
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case '?':
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case '*':
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case '+': {
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boolean greedy = true;
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if (index + 1 < array.length && array[index + 1] == '?') {
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greedy = false;
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++ index;
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}
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current.push(new Repeat(current.pop(),
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c == '+' ? 1 : 0, c == '?' ? 1 : -1, greedy));
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continue;
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}
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case '{': {
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++ index;
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int length = characterClassParser.digits(index, 8, 10);
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int min = Integer.parseInt(regex.substring(index, index + length));
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int max = min;
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index += length - 1;
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c = index + 1 < array.length ? array[index + 1] : 0;
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if (c == ',') {
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++ index;
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length = characterClassParser.digits(index + 1, 8, 10);
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max = length == 0 ? -1 :
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Integer.parseInt(regex.substring(index + 1, index + 1 + length));
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index += length;
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c = index + 1< array.length ? array[index + 1] : 0;
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}
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if (c != '}') {
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throw new RuntimeException("Invalid quantifier @" + index + ": "
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+ regex);
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}
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++ index;
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boolean greedy = true;
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if (index + 1 < array.length && array[index + 1] == '?') {
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++ index;
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greedy = false;
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}
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current.push(new Repeat(current.pop(), min, max, greedy));
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continue;
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}
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case '(': {
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boolean capturing = true;
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if (index + 1 < array.length && array[index + 1] == '?') {
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index += 2;
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if (index >= array.length) {
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throw new RuntimeException("Short pattern @" + index + ": "
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+ regex);
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}
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c = array[index];
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boolean lookAhead = true;
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if (c == '<') {
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if (++ index >= array.length) {
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throw new RuntimeException("Short pattern @" + index + ": "
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+ regex);
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}
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lookAhead = false;
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c = array[index];
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if (c != '=' && c != '!') {
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throw new IllegalArgumentException("Named groups not supported @"
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+ index + ": " + regex);
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}
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}
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switch (c) {
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case ':':
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capturing = false;
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break;
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case '!':
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case '=': {
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capturing = false;
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Lookaround lookaround = new Lookaround(lookAhead, c == '!');
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current.push(lookaround);
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groups.push(lookaround.group);
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continue;
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}
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default:
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throw new UnsupportedOperationException("Not yet supported: "
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+ regex.substring(index));
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}
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}
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current.push(groups.push(new Group(capturing, null)));
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continue;
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}
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case ')':
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if (groups.size() < 2) {
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throw new RuntimeException("Invalid group close @" + index + ": "
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+ regex);
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}
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groups.pop();
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continue;
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case '[': {
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CharacterMatcher matcher = characterClassParser.parseClass(index);
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if (matcher == null) {
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throw new RuntimeException("Invalid range @" + index + ": " + regex);
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}
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current.push(new CharacterRange(matcher));
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index = characterClassParser.getEndOffset() - 1;
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continue;
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}
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case '|':
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current.startAlternative();
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continue;
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case '^':
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current.push(LINE_START);
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continue;
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case '$':
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current.push(LINE_END);
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continue;
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default:
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throw new RuntimeException("Parse error @" + index + ": " + regex);
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}
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}
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if (groups.size() != 1) {
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throw new IllegalArgumentException("Unclosed groups: ("
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+ (groups.size() - 1) + "): " + regex);
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}
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PikeVM vm = new Output(root).toVM();
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String plain = vm.isPlainString();
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if (plain != null) {
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return new TrivialPattern(regex, plain, 0);
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}
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return new RegexPattern(regex, 0, vm);
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}
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}
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