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avoid catastrophic backtracking #99

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avoid catastrophic backtracking #99

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132 changes: 105 additions & 27 deletions src/color.js
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Expand Up @@ -5,16 +5,14 @@ export function Color() {}
export var darker = 0.7;
export var brighter = 1 / darker;

var reI = "\\s*([+-]?\\d+)\\s*",
reN = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)\\s*",
reP = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)%\\s*",
reHex = /^#([0-9a-f]{3,8})$/,
reRgbInteger = new RegExp("^rgb\\(" + [reI, reI, reI] + "\\)$"),
reRgbPercent = new RegExp("^rgb\\(" + [reP, reP, reP] + "\\)$"),
reRgbaInteger = new RegExp("^rgba\\(" + [reI, reI, reI, reN] + "\\)$"),
reRgbaPercent = new RegExp("^rgba\\(" + [reP, reP, reP, reN] + "\\)$"),
reHslPercent = new RegExp("^hsl\\(" + [reN, reP, reP] + "\\)$"),
reHslaPercent = new RegExp("^hsla\\(" + [reN, reP, reP, reN] + "\\)$");
var reHex = /#([0-9a-fA-F]{3,8})/y,
reFuncl = /(\w+)\(/y,
reFuncr = /\)/y,
reSpace = /\s+/y,
reComma = /,/y,
reInteger = /([+-]?\d+)/y,
reNumber = /([+-]?\d*\.?\d+(?:[eE][+-]?\d+)?)/y,
rePercent = /(?=([+-]?\d*\.?\d+(?:[eE][+-]?\d+)?))\1%/y; // https://blog.stevenlevithan.com/archives/mimic-atomic-groups

var named = {
aliceblue: 0xf0f8ff,
Expand Down Expand Up @@ -193,23 +191,103 @@ function color_formatRgb() {
return this.rgb().formatRgb();
}

export default function color(format) {
var m, l;
format = (format + "").trim().toLowerCase();
return (m = reHex.exec(format)) ? (l = m[1].length, m = parseInt(m[1], 16), l === 6 ? rgbn(m) // #ff0000
: l === 3 ? new Rgb((m >> 8 & 0xf) | (m >> 4 & 0xf0), (m >> 4 & 0xf) | (m & 0xf0), ((m & 0xf) << 4) | (m & 0xf), 1) // #f00
: l === 8 ? rgba(m >> 24 & 0xff, m >> 16 & 0xff, m >> 8 & 0xff, (m & 0xff) / 0xff) // #ff000000
: l === 4 ? rgba((m >> 12 & 0xf) | (m >> 8 & 0xf0), (m >> 8 & 0xf) | (m >> 4 & 0xf0), (m >> 4 & 0xf) | (m & 0xf0), (((m & 0xf) << 4) | (m & 0xf)) / 0xff) // #f000
: null) // invalid hex
: (m = reRgbInteger.exec(format)) ? new Rgb(m[1], m[2], m[3], 1) // rgb(255, 0, 0)
: (m = reRgbPercent.exec(format)) ? new Rgb(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, 1) // rgb(100%, 0%, 0%)
: (m = reRgbaInteger.exec(format)) ? rgba(m[1], m[2], m[3], m[4]) // rgba(255, 0, 0, 1)
: (m = reRgbaPercent.exec(format)) ? rgba(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, m[4]) // rgb(100%, 0%, 0%, 1)
: (m = reHslPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, 1) // hsl(120, 50%, 50%)
: (m = reHslaPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, m[4]) // hsla(120, 50%, 50%, 1)
: named.hasOwnProperty(format) ? rgbn(named[format]) // eslint-disable-line no-prototype-builtins
: format === "transparent" ? new Rgb(NaN, NaN, NaN, 0)
: null;
export default function color(input) {
input = `${input}`; // coerce to string
const state = {input, token: null, index: 0};
if (parseToken(state, reHex)) { // hexadecimal
if (!parseEnd(state)) return null;
const l = state.token.length;
const i = parseInt(state.token, 16);
return l === 6 ? rgbn(i) // #ff0000
: l === 3 ? new Rgb((i >> 8 & 0xf) | (i >> 4 & 0xf0), (i >> 4 & 0xf) | (i & 0xf0), ((i & 0xf) << 4) | (i & 0xf), 1) // #f00
: l === 8 ? rgba(i >> 24 & 0xff, i >> 16 & 0xff, i >> 8 & 0xff, (i & 0xff) / 0xff) // #ff000000
: l === 4 ? rgba((i >> 12 & 0xf) | (i >> 8 & 0xf0), (i >> 8 & 0xf) | (i >> 4 & 0xf0), (i >> 4 & 0xf) | (i & 0xf0), (((i & 0xf) << 4) | (i & 0xf)) / 0xff) // #f000
: null; // invalid hex
}
if (parseToken(state, reFuncl)) { // functional
switch (state.token.toLowerCase()) {
case "rgb": {
let r, g, b;
if (parseToken(state, rePercent)) { // rgb(100%, 0%, 0%)
return (r = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (g = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (b = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? new Rgb(r * 255 / 100, g * 255 / 100, b * 255 / 100, 1)
: null;
} else if (parseToken(state, reInteger)) { // rgb(255, 0, 0)
return (r = state.token, parseToken(state, reComma)) && parseToken(state, reInteger)
&& (g = state.token, parseToken(state, reComma)) && parseToken(state, reInteger)
&& (b = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? new Rgb(r, g, b, 1)
: null;
}
return null;
}
case "rgba": {
let r, g, b, a;
if (parseToken(state, rePercent)) { // rgb(100%, 0%, 0%)
return (r = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (g = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (b = state.token, parseToken(state, reComma)) && parseToken(state, reNumber)
&& (a = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? rgba(r * 255 / 100, g * 255 / 100, b * 255 / 100, a)
: null;
} else if (parseToken(state, reInteger)) { // rgb(255, 0, 0)
return (r = state.token, parseToken(state, reComma)) && parseToken(state, reInteger)
&& (g = state.token, parseToken(state, reComma)) && parseToken(state, reInteger)
&& (b = state.token, parseToken(state, reComma)) && parseToken(state, reNumber)
&& (a = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? rgba(r, g, b, a)
: null;
}
return null;
}
case "hsl": { // hsl(120, 50%, 50%)
let h, s, l;
return parseToken(state, reNumber)
&& (h = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (s = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (l = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? hsla(h, s / 100, l / 100, 1)
: null;
}
case "hsla": {
let h, s, l, a;
return parseToken(state, reNumber)
&& (h = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (s = state.token, parseToken(state, reComma)) && parseToken(state, rePercent)
&& (l = state.token, parseToken(state, reComma)) && parseToken(state, reNumber)
&& (a = state.token, parseToken(state, reFuncr)) && parseEnd(state)
? hsla(h, s / 100, l / 100, a)
: null;
}
}
return null; // unknown function
}
input = input.trim().toLowerCase(); // trim and downcase
return named.hasOwnProperty(input) ? rgbn(named[input]) // eslint-disable-line no-prototype-builtins
: input === "transparent" ? new Rgb(NaN, NaN, NaN, 0)
: null;
}

function skipSpace(state) {
reSpace.lastIndex = state.index;
if (reSpace.test(state.input)) state.index = reSpace.lastIndex;
}

function parseToken(state, re) {
skipSpace(state);
re.lastIndex = state.index;
const match = re.exec(state.input);
if (match === null) return false;
state.index = re.lastIndex;
state.token = match[1];
return true;
}

function parseEnd(state) {
skipSpace(state);
return state.index === state.input.length;
}

function rgbn(n) {
Expand Down
4 changes: 4 additions & 0 deletions test/color-test.js
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Expand Up @@ -59,6 +59,10 @@ it("color(format) parses HSLA format (e.g., \"hsla(60,100%,20%,0.4)\")", () => {
assertHslEqual(color("hsla(60,100%,20%,0.4)"), 60, 1, 0.2, 0.4);
});

it("color(format) disallows invalid hexadecimal (e.g., \"#abcdef no\")", () => {
assert.strictEqual(color("#abcdef no"), null);
});

it("color(format) ignores leading and trailing whitespace", () => {
assertRgbApproxEqual(color(" aliceblue\t\n"), 240, 248, 255, 1);
assertRgbApproxEqual(color(" #abc\t\n"), 170, 187, 204, 1);
Expand Down