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external/cmapscompress/compress.mjs

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+/* Copyright 2014 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.
+ */
+
+import fs from "fs";
+import { optimizeCMap } from "./optimize.mjs";
+import { parseAdobeCMap } from "./parse.mjs";
+import path from "path";
+
+function compressCmap(srcPath, destPath, verify) {
+  const content = fs.readFileSync(srcPath).toString();
+  const inputData = parseAdobeCMap(content);
+  optimizeCMap(inputData);
+
+  let out = writeByte((inputData.type << 1) | inputData.wmode);
+  if (inputData.comment) {
+    out += writeByte(0xe0) + writeString(inputData.comment);
+  }
+  if (inputData.usecmap) {
+    out += writeByte(0xe1) + writeString(inputData.usecmap);
+  }
+  let i = 0;
+  while (i < inputData.body.length) {
+    const item = inputData.body[i++],
+      subitems = item.items;
+    const first = item.items[0];
+    const sequence = item.sequence === true;
+    const flags = (item.type << 5) | (sequence ? 0x10 : 0);
+    let nextStart, nextCode;
+    switch (item.type) {
+      case 0:
+        out +=
+          writeByte(flags | getHexSize(first.start)) +
+          writeNumber(subitems.length);
+        out += first.start + writeNumber(subHex(first.end, first.start));
+        nextStart = incHex(first.end);
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            writeNumber(subHex(subitems[j].start, nextStart)) +
+            writeNumber(subHex(subitems[j].end, subitems[j].start));
+          nextStart = incHex(subitems[j].end);
+        }
+        break;
+      case 1:
+        out +=
+          writeByte(flags | getHexSize(first.start)) +
+          writeNumber(subitems.length);
+        out +=
+          first.start +
+          writeNumber(subHex(first.end, first.start)) +
+          writeNumber(first.code);
+        nextStart = incHex(first.end);
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            writeNumber(subHex(subitems[j].start, nextStart)) +
+            writeNumber(subHex(subitems[j].end, subitems[j].start)) +
+            writeNumber(subitems[j].code);
+          nextStart = incHex(subitems[j].end);
+        }
+        break;
+      case 2:
+        out +=
+          writeByte(flags | getHexSize(first.char)) +
+          writeNumber(subitems.length);
+        out += first.char + writeNumber(first.code);
+        nextStart = incHex(first.char);
+        nextCode = first.code + 1;
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            (sequence ? "" : writeNumber(subHex(subitems[j].char, nextStart))) +
+            writeSigned(subitems[j].code - nextCode);
+          nextStart = incHex(subitems[j].char);
+          nextCode = item.items[j].code + 1;
+        }
+        break;
+      case 3:
+        out +=
+          writeByte(flags | getHexSize(first.start)) +
+          writeNumber(subitems.length);
+        out +=
+          first.start +
+          writeNumber(subHex(first.end, first.start)) +
+          writeNumber(first.code);
+        nextStart = incHex(first.end);
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            (sequence
+              ? ""
+              : writeNumber(subHex(subitems[j].start, nextStart))) +
+            writeNumber(subHex(subitems[j].end, subitems[j].start)) +
+            writeNumber(subitems[j].code);
+          nextStart = incHex(subitems[j].end);
+        }
+        break;
+      case 4:
+        out +=
+          writeByte(flags | getHexSize(first.code)) +
+          writeNumber(subitems.length);
+        out += first.char + first.code;
+        nextStart = incHex(first.char);
+        nextCode = incHex(first.code);
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            (sequence ? "" : writeNumber(subHex(subitems[j].char, nextStart))) +
+            writeSigned(subHex(subitems[j].code, nextCode));
+          nextStart = incHex(subitems[j].char);
+          nextCode = incHex(subitems[j].code);
+        }
+        break;
+      case 5:
+        out +=
+          writeByte(flags | getHexSize(first.code)) +
+          writeNumber(subitems.length);
+        out +=
+          first.start +
+          writeNumber(subHex(first.end, first.start)) +
+          first.code;
+        nextStart = incHex(first.end);
+        for (let j = 1; j < subitems.length; j++) {
+          out +=
+            (sequence
+              ? ""
+              : writeNumber(subHex(subitems[j].start, nextStart))) +
+            writeNumber(subHex(subitems[j].end, subitems[j].start)) +
+            subitems[j].code;
+          nextStart = incHex(subitems[j].end);
+        }
+        break;
+    }
+  }
+
+  fs.writeFileSync(destPath, Buffer.from(out, "hex"));
+
+  if (verify) {
+    const result2 = parseCMap(out);
+    const isGood = JSON.stringify(inputData) === JSON.stringify(result2);
+    if (!isGood) {
+      throw new Error("Extracted data does not match the expected result");
+    }
+  }
+
+  return {
+    orig: fs.statSync(srcPath).size,
+    packed: out.length >> 1,
+  };
+}
+
+function parseCMap(binaryData) {
+  const reader = {
+    buffer: binaryData,
+    pos: 0,
+    end: binaryData.length,
+    readByte() {
+      if (this.pos >= this.end) {
+        return -1;
+      }
+      const d1 = fromHexDigit(this.buffer[this.pos]);
+      const d2 = fromHexDigit(this.buffer[this.pos + 1]);
+      this.pos += 2;
+      return (d1 << 4) | d2;
+    },
+    readNumber() {
+      let n = 0;
+      let last;
+      do {
+        const b = this.readByte();
+        last = !(b & 0x80);
+        n = (n << 7) | (b & 0x7f);
+      } while (!last);
+      return n;
+    },
+    readSigned() {
+      const n = this.readNumber();
+      return n & 1 ? -(n >>> 1) - 1 : n >>> 1;
+    },
+    readHex(size) {
+      const lengthInChars = (size + 1) << 1;
+      const s = this.buffer.substring(this.pos, this.pos + lengthInChars);
+      this.pos += lengthInChars;
+      return s;
+    },
+    readHexNumber(size) {
+      const lengthInChars = (size + 1) << 1,
+        stack = [];
+      let last;
+      do {
+        const b = this.readByte();
+        last = !(b & 0x80);
+        stack.push(b & 0x7f);
+      } while (!last);
+      let s = "",
+        buffer = 0,
+        bufferSize = 0;
+      while (s.length < lengthInChars) {
+        while (bufferSize < 4 && stack.length > 0) {
+          buffer |= stack.pop() << bufferSize;
+          bufferSize += 7;
+        }
+        s = toHexDigit(buffer & 15) + s;
+        buffer >>= 4;
+        bufferSize -= 4;
+      }
+      return s;
+    },
+    readHexSigned(size) {
+      const num = this.readHexNumber(size);
+      const sign = fromHexDigit(num.at(-1)) & 1 ? 15 : 0;
+      let c = 0;
+      let result = "";
+      for (const digit of num) {
+        c = (c << 4) | fromHexDigit(digit);
+        result += toHexDigit(sign ? (c >> 1) ^ sign : c >> 1);
+        c &= 1;
+      }
+      return result;
+    },
+    readString() {
+      const len = this.readNumber();
+      let s = "";
+      for (let i = 0; i < len; i++) {
+        s += String.fromCharCode(this.readNumber());
+      }
+      return s;
+    },
+  };
+
+  const header = reader.readByte();
+  const result = {
+    type: header >> 1,
+    wmode: header & 1,
+    comment: null,
+    usecmap: null,
+    body: [],
+  };
+
+  let b;
+  while ((b = reader.readByte()) >= 0) {
+    const type = b >> 5;
+    if (type === 7) {
+      switch (b & 0x1f) {
+        case 0:
+          result.comment = reader.readString();
+          break;
+        case 1:
+          result.usecmap = reader.readString();
+          break;
+      }
+      continue;
+    }
+    const sequence = !!(b & 0x10);
+    const dataSize = b & 15;
+    const subitems = [];
+    const item = {
+      type,
+      items: subitems,
+    };
+    if (sequence) {
+      item.sequence = true;
+    }
+    const ucs2DataSize = 1;
+    const subitemsCount = reader.readNumber();
+    let start, end, code, char;
+    switch (type) {
+      case 0:
+        start = reader.readHex(dataSize);
+        end = addHex(reader.readHexNumber(dataSize), start);
+        subitems.push({ start, end });
+        for (let i = 1; i < subitemsCount; i++) {
+          start = addHex(reader.readHexNumber(dataSize), incHex(end));
+          end = addHex(reader.readHexNumber(dataSize), start);
+          subitems.push({ start, end });
+        }
+        break;
+      case 1:
+        start = reader.readHex(dataSize);
+        end = addHex(reader.readHexNumber(dataSize), start);
+        code = reader.readNumber();
+        subitems.push({ start, end, code });
+        for (let i = 1; i < subitemsCount; i++) {
+          start = addHex(reader.readHexNumber(dataSize), incHex(end));
+          end = addHex(reader.readHexNumber(dataSize), start);
+          code = reader.readNumber();
+          subitems.push({ start, end, code });
+        }
+        break;
+      case 2:
+        char = reader.readHex(dataSize);
+        code = reader.readNumber();
+        subitems.push({ char, code });
+        for (let i = 1; i < subitemsCount; i++) {
+          char = sequence
+            ? incHex(char)
+            : addHex(reader.readHexNumber(dataSize), incHex(char));
+          code = reader.readSigned() + (code + 1);
+          subitems.push({ char, code });
+        }
+        break;
+      case 3:
+        start = reader.readHex(dataSize);
+        end = addHex(reader.readHexNumber(dataSize), start);
+        code = reader.readNumber();
+        subitems.push({ start, end, code });
+        for (let i = 1; i < subitemsCount; i++) {
+          start = sequence
+            ? incHex(end)
+            : addHex(reader.readHexNumber(dataSize), incHex(end));
+          end = addHex(reader.readHexNumber(dataSize), start);
+          code = reader.readNumber();
+          subitems.push({ start, end, code });
+        }
+        break;
+      case 4:
+        char = reader.readHex(ucs2DataSize);
+        code = reader.readHex(dataSize);
+        subitems.push({ char, code });
+        for (let i = 1; i < subitemsCount; i++) {
+          char = sequence
+            ? incHex(char)
+            : addHex(reader.readHexNumber(ucs2DataSize), incHex(char));
+          code = addHex(reader.readHexSigned(dataSize), incHex(code));
+          subitems.push({ char, code });
+        }
+        break;
+      case 5:
+        start = reader.readHex(ucs2DataSize);
+        end = addHex(reader.readHexNumber(ucs2DataSize), start);
+        code = reader.readHex(dataSize);
+        subitems.push({ start, end, code });
+        for (let i = 1; i < subitemsCount; i++) {
+          start = sequence
+            ? incHex(end)
+            : addHex(reader.readHexNumber(ucs2DataSize), incHex(end));
+          end = addHex(reader.readHexNumber(ucs2DataSize), start);
+          code = reader.readHex(dataSize);
+          subitems.push({ start, end, code });
+        }
+        break;
+      default:
+        throw new Error("Unknown type: " + type);
+    }
+    result.body.push(item);
+  }
+
+  return result;
+}
+
+function toHexDigit(n) {
+  return n.toString(16);
+}
+function fromHexDigit(s) {
+  return parseInt(s, 16);
+}
+function getHexSize(s) {
+  return (s.length >> 1) - 1;
+}
+function writeByte(b) {
+  return toHexDigit((b >> 4) & 15) + toHexDigit(b & 15);
+}
+function writeNumber(n) {
+  if (typeof n === "string") {
+    let s = "",
+      buffer = 0,
+      bufferSize = 0;
+    let i = n.length;
+    while (i > 0) {
+      --i;
+      buffer |= fromHexDigit(n[i]) << bufferSize;
+      bufferSize += 4;
+      if (bufferSize >= 7) {
+        s = writeByte((buffer & 0x7f) | (s.length > 0 ? 0x80 : 0)) + s;
+        buffer >>>= 7;
+        bufferSize -= 7;
+      }
+    }
+    if (buffer > 0) {
+      s = writeByte((buffer & 0x7f) | (s.length > 0 ? 0x80 : 0)) + s;
+    }
+    while (s.indexOf("80") === 0) {
+      s = s.substring(2);
+    }
+    return s;
+  }
+  let s = writeByte(n & 0x7f);
+  n >>>= 7;
+  while (n > 0) {
+    s = writeByte((n & 0x7f) | 0x80) + s;
+    n >>>= 7;
+  }
+  return s;
+}
+function writeSigned(n) {
+  if (typeof n === "string") {
+    let t = "";
+    let c = fromHexDigit(n[0]);
+    const neg = c >= 8;
+    c = neg ? c ^ 15 : c;
+    for (let i = 1; i < n.length; i++) {
+      const d = fromHexDigit(n[i]);
+      c = (c << 4) | (neg ? d ^ 15 : d);
+      t += toHexDigit(c >> 3);
+      c &= 7;
+    }
+    t += toHexDigit((c << 1) | (neg ? 1 : 0));
+    return writeNumber(t);
+  }
+  return n < 0 ? writeNumber(-2 * n - 1) : writeNumber(2 * n);
+}
+function writeString(s) {
+  let t = writeNumber(s.length);
+  for (let i = 0; i < s.length; i++) {
+    t += writeNumber(s.charCodeAt(i));
+  }
+  return t;
+}
+function addHex(a, b) {
+  let c = 0,
+    s = "";
+  for (let i = a.length - 1; i >= 0; i--) {
+    c += fromHexDigit(a[i]) + fromHexDigit(b[i]);
+    if (c >= 16) {
+      s = toHexDigit(c - 16) + s;
+      c = 1;
+    } else {
+      s = toHexDigit(c) + s;
+      c = 0;
+    }
+  }
+  return s;
+}
+function subHex(a, b) {
+  let c = 0,
+    s = "";
+  for (let i = a.length - 1; i >= 0; i--) {
+    c += fromHexDigit(a[i]) - fromHexDigit(b[i]);
+    if (c < 0) {
+      s = toHexDigit(c + 16) + s;
+      c = -1;
+    } else {
+      s = toHexDigit(c) + s;
+      c = 0;
+    }
+  }
+  return s;
+}
+function incHex(a) {
+  let c = 1,
+    s = "";
+  for (let i = a.length - 1; i >= 0; i--) {
+    c += fromHexDigit(a[i]);
+    if (c >= 16) {
+      s = toHexDigit(c - 16) + s;
+      c = 1;
+    } else {
+      s = toHexDigit(c) + s;
+      c = 0;
+    }
+  }
+  return s;
+}
+
+function compressCmaps(src, dest, verify) {
+  const files = fs.readdirSync(src).filter(function (fn) {
+    return !fn.includes("."); // skipping files with the extension
+  });
+  files.forEach(function (fn) {
+    const srcPath = path.join(src, fn);
+    const destPath = path.join(dest, fn + ".bcmap");
+    const stats = compressCmap(srcPath, destPath, verify);
+    console.log(
+      "Compressing " +
+        fn +
+        ": " +
+        stats.orig +
+        " vs " +
+        stats.packed +
+        " " +
+        ((stats.packed / stats.orig) * 100).toFixed(1) +
+        "%"
+    );
+  });
+}
+
+export { compressCmaps };