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diff .cms/lib/codemirror/src/util/bidi.js @ 0:78edf6b517a0 draft
24.10
author | Coffee CMS <info@coffee-cms.ru> |
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date | Fri, 11 Oct 2024 22:40:23 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/.cms/lib/codemirror/src/util/bidi.js Fri Oct 11 22:40:23 2024 +0000 @@ -0,0 +1,215 @@ +import { lst } from "./misc.js" + +// BIDI HELPERS + +export function iterateBidiSections(order, from, to, f) { + if (!order) return f(from, to, "ltr", 0) + let found = false + for (let i = 0; i < order.length; ++i) { + let part = order[i] + if (part.from < to && part.to > from || from == to && part.to == from) { + f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr", i) + found = true + } + } + if (!found) f(from, to, "ltr") +} + +export let bidiOther = null +export function getBidiPartAt(order, ch, sticky) { + let found + bidiOther = null + for (let i = 0; i < order.length; ++i) { + let cur = order[i] + if (cur.from < ch && cur.to > ch) return i + if (cur.to == ch) { + if (cur.from != cur.to && sticky == "before") found = i + else bidiOther = i + } + if (cur.from == ch) { + if (cur.from != cur.to && sticky != "before") found = i + else bidiOther = i + } + } + return found != null ? found : bidiOther +} + +// Bidirectional ordering algorithm +// See http://unicode.org/reports/tr9/tr9-13.html for the algorithm +// that this (partially) implements. + +// One-char codes used for character types: +// L (L): Left-to-Right +// R (R): Right-to-Left +// r (AL): Right-to-Left Arabic +// 1 (EN): European Number +// + (ES): European Number Separator +// % (ET): European Number Terminator +// n (AN): Arabic Number +// , (CS): Common Number Separator +// m (NSM): Non-Spacing Mark +// b (BN): Boundary Neutral +// s (B): Paragraph Separator +// t (S): Segment Separator +// w (WS): Whitespace +// N (ON): Other Neutrals + +// Returns null if characters are ordered as they appear +// (left-to-right), or an array of sections ({from, to, level} +// objects) in the order in which they occur visually. +let bidiOrdering = (function() { + // Character types for codepoints 0 to 0xff + let lowTypes = "bbbbbbbbbtstwsbbbbbbbbbbbbbbssstwNN%%%NNNNNN,N,N1111111111NNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNbbbbbbsbbbbbbbbbbbbbbbbbbbbbbbbbb,N%%%%NNNNLNNNNN%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLN" + // Character types for codepoints 0x600 to 0x6f9 + let arabicTypes = "nnnnnnNNr%%r,rNNmmmmmmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmnNmmmmmmrrmmNmmmmrr1111111111" + function charType(code) { + if (code <= 0xf7) return lowTypes.charAt(code) + else if (0x590 <= code && code <= 0x5f4) return "R" + else if (0x600 <= code && code <= 0x6f9) return arabicTypes.charAt(code - 0x600) + else if (0x6ee <= code && code <= 0x8ac) return "r" + else if (0x2000 <= code && code <= 0x200b) return "w" + else if (code == 0x200c) return "b" + else return "L" + } + + let bidiRE = /[\u0590-\u05f4\u0600-\u06ff\u0700-\u08ac]/ + let isNeutral = /[stwN]/, isStrong = /[LRr]/, countsAsLeft = /[Lb1n]/, countsAsNum = /[1n]/ + + function BidiSpan(level, from, to) { + this.level = level + this.from = from; this.to = to + } + + return function(str, direction) { + let outerType = direction == "ltr" ? "L" : "R" + + if (str.length == 0 || direction == "ltr" && !bidiRE.test(str)) return false + let len = str.length, types = [] + for (let i = 0; i < len; ++i) + types.push(charType(str.charCodeAt(i))) + + // W1. Examine each non-spacing mark (NSM) in the level run, and + // change the type of the NSM to the type of the previous + // character. If the NSM is at the start of the level run, it will + // get the type of sor. + for (let i = 0, prev = outerType; i < len; ++i) { + let type = types[i] + if (type == "m") types[i] = prev + else prev = type + } + + // W2. Search backwards from each instance of a European number + // until the first strong type (R, L, AL, or sor) is found. If an + // AL is found, change the type of the European number to Arabic + // number. + // W3. Change all ALs to R. + for (let i = 0, cur = outerType; i < len; ++i) { + let type = types[i] + if (type == "1" && cur == "r") types[i] = "n" + else if (isStrong.test(type)) { cur = type; if (type == "r") types[i] = "R" } + } + + // W4. A single European separator between two European numbers + // changes to a European number. A single common separator between + // two numbers of the same type changes to that type. + for (let i = 1, prev = types[0]; i < len - 1; ++i) { + let type = types[i] + if (type == "+" && prev == "1" && types[i+1] == "1") types[i] = "1" + else if (type == "," && prev == types[i+1] && + (prev == "1" || prev == "n")) types[i] = prev + prev = type + } + + // W5. A sequence of European terminators adjacent to European + // numbers changes to all European numbers. + // W6. Otherwise, separators and terminators change to Other + // Neutral. + for (let i = 0; i < len; ++i) { + let type = types[i] + if (type == ",") types[i] = "N" + else if (type == "%") { + let end + for (end = i + 1; end < len && types[end] == "%"; ++end) {} + let replace = (i && types[i-1] == "!") || (end < len && types[end] == "1") ? "1" : "N" + for (let j = i; j < end; ++j) types[j] = replace + i = end - 1 + } + } + + // W7. Search backwards from each instance of a European number + // until the first strong type (R, L, or sor) is found. If an L is + // found, then change the type of the European number to L. + for (let i = 0, cur = outerType; i < len; ++i) { + let type = types[i] + if (cur == "L" && type == "1") types[i] = "L" + else if (isStrong.test(type)) cur = type + } + + // N1. A sequence of neutrals takes the direction of the + // surrounding strong text if the text on both sides has the same + // direction. European and Arabic numbers act as if they were R in + // terms of their influence on neutrals. Start-of-level-run (sor) + // and end-of-level-run (eor) are used at level run boundaries. + // N2. Any remaining neutrals take the embedding direction. + for (let i = 0; i < len; ++i) { + if (isNeutral.test(types[i])) { + let end + for (end = i + 1; end < len && isNeutral.test(types[end]); ++end) {} + let before = (i ? types[i-1] : outerType) == "L" + let after = (end < len ? types[end] : outerType) == "L" + let replace = before == after ? (before ? "L" : "R") : outerType + for (let j = i; j < end; ++j) types[j] = replace + i = end - 1 + } + } + + // Here we depart from the documented algorithm, in order to avoid + // building up an actual levels array. Since there are only three + // levels (0, 1, 2) in an implementation that doesn't take + // explicit embedding into account, we can build up the order on + // the fly, without following the level-based algorithm. + let order = [], m + for (let i = 0; i < len;) { + if (countsAsLeft.test(types[i])) { + let start = i + for (++i; i < len && countsAsLeft.test(types[i]); ++i) {} + order.push(new BidiSpan(0, start, i)) + } else { + let pos = i, at = order.length, isRTL = direction == "rtl" ? 1 : 0 + for (++i; i < len && types[i] != "L"; ++i) {} + for (let j = pos; j < i;) { + if (countsAsNum.test(types[j])) { + if (pos < j) { order.splice(at, 0, new BidiSpan(1, pos, j)); at += isRTL } + let nstart = j + for (++j; j < i && countsAsNum.test(types[j]); ++j) {} + order.splice(at, 0, new BidiSpan(2, nstart, j)) + at += isRTL + pos = j + } else ++j + } + if (pos < i) order.splice(at, 0, new BidiSpan(1, pos, i)) + } + } + if (direction == "ltr") { + if (order[0].level == 1 && (m = str.match(/^\s+/))) { + order[0].from = m[0].length + order.unshift(new BidiSpan(0, 0, m[0].length)) + } + if (lst(order).level == 1 && (m = str.match(/\s+$/))) { + lst(order).to -= m[0].length + order.push(new BidiSpan(0, len - m[0].length, len)) + } + } + + return direction == "rtl" ? order.reverse() : order + } +})() + +// Get the bidi ordering for the given line (and cache it). Returns +// false for lines that are fully left-to-right, and an array of +// BidiSpan objects otherwise. +export function getOrder(line, direction) { + let order = line.order + if (order == null) order = line.order = bidiOrdering(line.text, direction) + return order +}