pdfjs-dist/lib/core/bidi.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2021 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.bidi = bidi;

var _util = require("../shared/util.js");

const baseTypes = ["BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "S", "B", "S", "WS", "B", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "B", "B", "B", "S", "WS", "ON", "ON", "ET", "ET", "ET", "ON", "ON", "ON", "ON", "ON", "ES", "CS", "ES", "CS", "CS", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "CS", "ON", "ON", "ON", "ON", "ON", "ON", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "ON", "ON", "ON", "ON", "ON", "ON", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "ON", "ON", "ON", "ON", "BN", "BN", "BN", "BN", "BN", "BN", "B", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "BN", "CS", "ON", "ET", "ET", "ET", "ET", "ON", "ON", "ON", "ON", "L", "ON", "ON", "BN", "ON", "ON", "ET", "ET", "EN", "EN", "ON", "L", "ON", "ON", "ON", "EN", "L", "ON", "ON", "ON", "ON", "ON", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "ON", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "L", "ON", "L", "L", "L", "L", "L", "L", "L", "L"];
const arabicTypes = ["AN", "AN", "AN", "AN", "AN", "AN", "ON", "ON", "AL", "ET", "ET", "AL", "CS", "AL", "ON", "ON", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "AL", "AL", "", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "AN", "AN", "AN", "AN", "AN", "AN", "AN", "AN", "AN", "AN", "ET", "AN", "AN", "AL", "AL", "AL", "NSM", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "AN", "ON", "NSM", "NSM", "NSM", "NSM", "NSM", "NSM", "AL", "AL", "NSM", "NSM", "ON", "NSM", "NSM", "NSM", "NSM", "AL", "AL", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "EN", "AL", "AL", "AL", "AL", "AL", "AL"];

function isOdd(i) {
  return (i & 1) !== 0;
}

function isEven(i) {
  return (i & 1) === 0;
}

function findUnequal(arr, start, value) {
  let j, jj;

  for (j = start, jj = arr.length; j < jj; ++j) {
    if (arr[j] !== value) {
      return j;
    }
  }

  return j;
}

function setValues(arr, start, end, value) {
  for (let j = start; j < end; ++j) {
    arr[j] = value;
  }
}

function reverseValues(arr, start, end) {
  for (let i = start, j = end - 1; i < j; ++i, --j) {
    const temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
  }
}

function createBidiText(str, isLTR, vertical = false) {
  let dir = "ltr";

  if (vertical) {
    dir = "ttb";
  } else if (!isLTR) {
    dir = "rtl";
  }

  return {
    str,
    dir
  };
}

const chars = [];
const types = [];

function bidi(str, startLevel, vertical) {
  let isLTR = true;
  const strLength = str.length;

  if (strLength === 0 || vertical) {
    return createBidiText(str, isLTR, vertical);
  }

  chars.length = strLength;
  types.length = strLength;
  let numBidi = 0;
  let i, ii;

  for (i = 0; i < strLength; ++i) {
    chars[i] = str.charAt(i);
    const charCode = str.charCodeAt(i);
    let charType = "L";

    if (charCode <= 0x00ff) {
      charType = baseTypes[charCode];
    } else if (0x0590 <= charCode && charCode <= 0x05f4) {
      charType = "R";
    } else if (0x0600 <= charCode && charCode <= 0x06ff) {
      charType = arabicTypes[charCode & 0xff];

      if (!charType) {
        (0, _util.warn)("Bidi: invalid Unicode character " + charCode.toString(16));
      }
    } else if (0x0700 <= charCode && charCode <= 0x08ac) {
      charType = "AL";
    }

    if (charType === "R" || charType === "AL" || charType === "AN") {
      numBidi++;
    }

    types[i] = charType;
  }

  if (numBidi === 0) {
    isLTR = true;
    return createBidiText(str, isLTR);
  }

  if (startLevel === -1) {
    if (numBidi / strLength < 0.3) {
      isLTR = true;
      startLevel = 0;
    } else {
      isLTR = false;
      startLevel = 1;
    }
  }

  const levels = [];

  for (i = 0; i < strLength; ++i) {
    levels[i] = startLevel;
  }

  const e = isOdd(startLevel) ? "R" : "L";
  const sor = e;
  const eor = sor;
  let lastType = sor;

  for (i = 0; i < strLength; ++i) {
    if (types[i] === "NSM") {
      types[i] = lastType;
    } else {
      lastType = types[i];
    }
  }

  lastType = sor;
  let t;

  for (i = 0; i < strLength; ++i) {
    t = types[i];

    if (t === "EN") {
      types[i] = lastType === "AL" ? "AN" : "EN";
    } else if (t === "R" || t === "L" || t === "AL") {
      lastType = t;
    }
  }

  for (i = 0; i < strLength; ++i) {
    t = types[i];

    if (t === "AL") {
      types[i] = "R";
    }
  }

  for (i = 1; i < strLength - 1; ++i) {
    if (types[i] === "ES" && types[i - 1] === "EN" && types[i + 1] === "EN") {
      types[i] = "EN";
    }

    if (types[i] === "CS" && (types[i - 1] === "EN" || types[i - 1] === "AN") && types[i + 1] === types[i - 1]) {
      types[i] = types[i - 1];
    }
  }

  for (i = 0; i < strLength; ++i) {
    if (types[i] === "EN") {
      for (let j = i - 1; j >= 0; --j) {
        if (types[j] !== "ET") {
          break;
        }

        types[j] = "EN";
      }

      for (let j = i + 1; j < strLength; ++j) {
        if (types[j] !== "ET") {
          break;
        }

        types[j] = "EN";
      }
    }
  }

  for (i = 0; i < strLength; ++i) {
    t = types[i];

    if (t === "WS" || t === "ES" || t === "ET" || t === "CS") {
      types[i] = "ON";
    }
  }

  lastType = sor;

  for (i = 0; i < strLength; ++i) {
    t = types[i];

    if (t === "EN") {
      types[i] = lastType === "L" ? "L" : "EN";
    } else if (t === "R" || t === "L") {
      lastType = t;
    }
  }

  for (i = 0; i < strLength; ++i) {
    if (types[i] === "ON") {
      const end = findUnequal(types, i + 1, "ON");
      let before = sor;

      if (i > 0) {
        before = types[i - 1];
      }

      let after = eor;

      if (end + 1 < strLength) {
        after = types[end + 1];
      }

      if (before !== "L") {
        before = "R";
      }

      if (after !== "L") {
        after = "R";
      }

      if (before === after) {
        setValues(types, i, end, before);
      }

      i = end - 1;
    }
  }

  for (i = 0; i < strLength; ++i) {
    if (types[i] === "ON") {
      types[i] = e;
    }
  }

  for (i = 0; i < strLength; ++i) {
    t = types[i];

    if (isEven(levels[i])) {
      if (t === "R") {
        levels[i] += 1;
      } else if (t === "AN" || t === "EN") {
        levels[i] += 2;
      }
    } else {
      if (t === "L" || t === "AN" || t === "EN") {
        levels[i] += 1;
      }
    }
  }

  let highestLevel = -1;
  let lowestOddLevel = 99;
  let level;

  for (i = 0, ii = levels.length; i < ii; ++i) {
    level = levels[i];

    if (highestLevel < level) {
      highestLevel = level;
    }

    if (lowestOddLevel > level && isOdd(level)) {
      lowestOddLevel = level;
    }
  }

  for (level = highestLevel; level >= lowestOddLevel; --level) {
    let start = -1;

    for (i = 0, ii = levels.length; i < ii; ++i) {
      if (levels[i] < level) {
        if (start >= 0) {
          reverseValues(chars, start, i);
          start = -1;
        }
      } else if (start < 0) {
        start = i;
      }
    }

    if (start >= 0) {
      reverseValues(chars, start, levels.length);
    }
  }

  for (i = 0, ii = chars.length; i < ii; ++i) {
    const ch = chars[i];

    if (ch === "<" || ch === ">") {
      chars[i] = "";
    }
  }

  return createBidiText(chars.join(""), isLTR);
}