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Regex: implement counted quantifiers: {<n>,<m>}

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Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This commit is contained in:
Johannes Schindelin 2013-11-20 10:15:43 -06:00
parent fb6486e276
commit c975e25864
2 changed files with 71 additions and 20 deletions
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5
test/Regex.java
View File

@ -87,5 +87,10 @@ public class Regex {
expectSplit("o.*?$", "Hello\r\nHobbes!", "Hello\r\nH");
expectSplit("\\b", "a+ b + c\nd", "", "a", "+ ", "b", " + ", "c", "\n", "d");
expectSplit("\\B", "Hi Cal!", "H", "i C", "a", "l!");
expectMatch("a{2,5}", "aaaa");
expectGroups("a??(a{2,5}?)", "aaaa", "aaaa");
expectGroups("a??(a{3}?)", "aaaa", "aaa");
expectNoMatch("a(a{3}?)", "aaaaa");
expectMatch("a(a{3,}?)", "aaaaa");
}
}

86
test/regex/Compiler.java
View File

@ -114,11 +114,16 @@ class Compiler implements PikeVMOpcodes {
private boolean greedy;
public Repeat(Expression expr, int minCount, int maxCount, boolean greedy) {
if (minCount != 0 && minCount != 1) {
if (minCount < 0) {
throw new RuntimeException("Unexpected min count: " + minCount);
}
if (maxCount != 1 && maxCount != -1) {
throw new RuntimeException("Unexpected max count: " + maxCount);
if (maxCount != -1) {
if (maxCount == 0) {
throw new RuntimeException("Unexpected max count: " + maxCount);
}
if (minCount > maxCount) {
throw new RuntimeException("Unexpected range: " + minCount + ", " + maxCount);
}
}
this.expr = expr;
this.minCount = minCount;
@ -130,25 +135,38 @@ class Compiler implements PikeVMOpcodes {
int start = output.offset;
int splitJmp = greedy ? SPLIT_JMP : SPLIT;
int split = greedy ? SPLIT : SPLIT_JMP;
if (minCount == 1 && maxCount == -1) {
for (int i = 1; i < minCount; ++ i) {
expr.writeCode(output);
output.add(splitJmp);
output.add(start);
} else if (minCount == 0 && maxCount == -1) {
output.add(split);
int jump = output.markJump();
expr.writeCode(output);
output.add(splitJmp);
output.add(start + 2);
output.setJump(jump);
} else if (minCount == 0 && maxCount == 1) {
output.add(split);
int jump = output.markJump();
expr.writeCode(output);
output.setJump(jump);
}
if (maxCount == -1) {
if (minCount > 0) {
int jump = output.offset;
expr.writeCode(output);
output.add(splitJmp);
output.add(jump);
} else {
output.add(split);
int jump = output.markJump();
expr.writeCode(output);
output.add(splitJmp);
output.add(start + 2);
output.setJump(jump);
}
} else {
throw new RuntimeException("Unexpected range: "
+ minCount + ", " + maxCount);
if (minCount > 0) {
expr.writeCode(output);
}
if (maxCount > minCount) {
int[] jumps = new int[maxCount - minCount];
for (int i = 0; i < jumps.length; ++ i) {
output.add(split);
jumps[i] = output.markJump();
expr.writeCode(output);
}
for (int jump : jumps) {
output.setJump(jump);
}
}
}
}
}
@ -328,6 +346,34 @@ class Compiler implements PikeVMOpcodes {
c == '+' ? 1 : 0, c == '?' ? 1 : -1, greedy));
continue;
}
case '{': {
++ index;
int length = characterClassParser.digits(index, 8, 10);
int min = Integer.parseInt(regex.substring(index, index + length));
int max = min;
index += length - 1;
c = index + 1 < array.length ? array[index + 1] : 0;
if (c == ',') {
++ index;
length = characterClassParser.digits(index + 1, 8, 10);
max = length == 0 ? -1 :
Integer.parseInt(regex.substring(index + 1, index + 1 + length));
index += length;
c = index + 1< array.length ? array[index + 1] : 0;
}
if (c != '}') {
throw new RuntimeException("Invalid quantifier @" + index + ": "
+ regex);
}
++ index;
boolean greedy = true;
if (index + 1 < array.length && array[index + 1] == '?') {
++ index;
greedy = false;
}
current.push(new Repeat(current.pop(), min, max, greedy));
continue;
}
case '(': {
boolean capturing = true;
if (index + 1 < array.length && array[index + 1] == '?') {