Copy all functions exported by _path.js and path.js into minifyPathDa…

…ta.js (#12)

* Move all stringifying functions into plugin.

plugins/minifyPathData.js

@@ -1,16 +1,40 @@
-import { path2js, js2path } from './_path.js';
 import { pathElems } from './_collections.js';
-import { cleanupOutData, exactAdd } from '../lib/svgo/tools.js';
+import { cleanupOutData, exactAdd, minifyNumber } from '../lib/svgo/tools.js';
 
 /**
  * @typedef {import('../lib/types.js').PathDataItem} PathDataItem
+ * @typedef {import('../lib/types.js').PathDataCommand} PathDataCommand
+ * @typedef {'none' | 'sign' | 'whole' | 'decimal_point' | 'decimal' | 'e' | 'exponent_sign' | 'exponent'} ReadNumberState
  * @typedef {import('../lib/types.js').PathDataItem&{base?:number[],coords?:[number,number]}} InitialExtendedPathDataItem
  * @typedef {import('../lib/types.js').PathDataItem&{base:number[],coords:[number,number]}} ExtendedPathDataItem
  */
 
 export const name = 'minifyPathData';
 export const description = 'writes path data in shortest form';
 
+const argsCountPerCommand = {
+  M: 2,
+  m: 2,
+  Z: 0,
+  z: 0,
+  L: 2,
+  l: 2,
+  H: 1,
+  h: 1,
+  V: 1,
+  v: 1,
+  C: 6,
+  c: 6,
+  S: 4,
+  s: 4,
+  Q: 4,
+  q: 4,
+  T: 2,
+  t: 2,
+  A: 7,
+  a: 7,
+};
+
 /**
  * @see https://www.w3.org/TR/SVG11/paths.html#PathData
  *
@@ -36,7 +60,7 @@ export const fn = (root, params, info) => {
           data = filterCommands(data, computedStyle);
           data = convertToMixed(data);
           if (data.length) {
-            js2path(node, data, {});
+            node.attributes.d = stringifyPathData(data);
           }
         }
       },
@@ -347,3 +371,297 @@ function filterCommands(pathData, styles) {
     return true;
   });
 }
+
+/**
+ * @type {(c: string) => c is PathDataCommand}
+ */
+const isCommand = (c) => {
+  return c in argsCountPerCommand;
+};
+
+/**
+ * @param {string} c
+ * @returns {boolean}
+ */
+const isDigit = (c) => {
+  const codePoint = c.codePointAt(0);
+  if (codePoint == null) {
+    return false;
+  }
+  return 48 <= codePoint && codePoint <= 57;
+};
+
+/**
+ * @param {string} c
+ * @returns {boolean}
+ */
+const isWhiteSpace = (c) => {
+  return c === ' ' || c === '\t' || c === '\r' || c === '\n';
+};
+
+/**
+ * @param {string} string
+ * @returns {PathDataItem[]}
+ */
+export const parsePathData = (string) => {
+  /**
+   * @type {PathDataItem[]}
+   */
+  const pathData = [];
+  /**
+   * @type {PathDataCommand|null}
+   */
+  let command = null;
+  let args = /** @type {number[]} */ ([]);
+  let argsCount = 0;
+  let canHaveComma = false;
+  let hadComma = false;
+  for (let i = 0; i < string.length; i += 1) {
+    const c = string.charAt(i);
+    if (isWhiteSpace(c)) {
+      continue;
+    }
+    // allow comma only between arguments
+    if (canHaveComma && c === ',') {
+      if (hadComma) {
+        break;
+      }
+      hadComma = true;
+      continue;
+    }
+    if (isCommand(c)) {
+      if (hadComma) {
+        return pathData;
+      }
+      if (command == null) {
+        // moveto should be leading command
+        if (c !== 'M' && c !== 'm') {
+          return pathData;
+        }
+      } else if (args.length !== 0) {
+        // stop if previous command arguments are not flushed
+        return pathData;
+      }
+      command = c;
+      args = [];
+      argsCount = argsCountPerCommand[command];
+      canHaveComma = false;
+      // flush command without arguments
+      if (argsCount === 0) {
+        pathData.push({ command, args });
+      }
+      continue;
+    }
+    // avoid parsing arguments if no command detected
+    if (command == null) {
+      return pathData;
+    }
+    // read next argument
+    let newCursor = i;
+    let number = null;
+    if (command === 'A' || command === 'a') {
+      const position = args.length;
+      if (position === 0 || position === 1) {
+        // allow only positive number without sign as first two arguments
+        if (c !== '+' && c !== '-') {
+          [newCursor, number] = readNumber(string, i);
+        }
+      }
+      if (position === 2 || position === 5 || position === 6) {
+        [newCursor, number] = readNumber(string, i);
+      }
+      if (position === 3 || position === 4) {
+        // read flags
+        if (c === '0') {
+          number = 0;
+        }
+        if (c === '1') {
+          number = 1;
+        }
+      }
+    } else {
+      [newCursor, number] = readNumber(string, i);
+    }
+    if (number == null) {
+      return pathData;
+    }
+    args.push(number);
+    canHaveComma = true;
+    hadComma = false;
+    i = newCursor;
+    // flush arguments when necessary count is reached
+    if (args.length === argsCount) {
+      pathData.push({ command, args });
+      // subsequent moveto coordinates are treated as implicit lineto commands
+      if (command === 'M') {
+        command = 'L';
+      }
+      if (command === 'm') {
+        command = 'l';
+      }
+      args = [];
+    }
+  }
+  return pathData;
+};
+
+/**
+ * @param {import('../lib/types.js').XastElement} path
+ * @returns {PathDataItem[]}
+ */
+function path2js(path) {
+  /**
+   * @type {PathDataItem[]}
+   */
+  const pathData = []; // JS representation of the path data
+  const newPathData = parsePathData(path.attributes.d);
+  for (const { command, args } of newPathData) {
+    pathData.push({ command, args });
+  }
+  // First moveto is actually absolute. Subsequent coordinates were separated above.
+  if (pathData.length && pathData[0].command == 'm') {
+    pathData[0].command = 'M';
+  }
+  return pathData;
+}
+
+/**
+ * @type {(string: string, cursor: number) => [number, ?number]}
+ */
+const readNumber = (string, cursor) => {
+  let i = cursor;
+  let value = '';
+  let state = /** @type {ReadNumberState} */ ('none');
+  for (; i < string.length; i += 1) {
+    const c = string[i];
+    if (c === '+' || c === '-') {
+      if (state === 'none') {
+        state = 'sign';
+        value += c;
+        continue;
+      }
+      if (state === 'e') {
+        state = 'exponent_sign';
+        value += c;
+        continue;
+      }
+    }
+    if (isDigit(c)) {
+      if (state === 'none' || state === 'sign' || state === 'whole') {
+        state = 'whole';
+        value += c;
+        continue;
+      }
+      if (state === 'decimal_point' || state === 'decimal') {
+        state = 'decimal';
+        value += c;
+        continue;
+      }
+      if (state === 'e' || state === 'exponent_sign' || state === 'exponent') {
+        state = 'exponent';
+        value += c;
+        continue;
+      }
+    }
+    if (c === '.') {
+      if (state === 'none' || state === 'sign' || state === 'whole') {
+        state = 'decimal_point';
+        value += c;
+        continue;
+      }
+    }
+    if (c === 'E' || c == 'e') {
+      if (
+        state === 'whole' ||
+        state === 'decimal_point' ||
+        state === 'decimal'
+      ) {
+        state = 'e';
+        value += c;
+        continue;
+      }
+    }
+    break;
+  }
+  const number = Number.parseFloat(value);
+  if (Number.isNaN(number)) {
+    return [cursor, null];
+  } else {
+    // step back to delegate iteration to parent loop
+    return [i - 1, number];
+  }
+};
+
+/**
+ * @param {PathDataItem[]} pathData
+ * @returns {string}
+ */
+function stringifyPathData(pathData) {
+  if (pathData.length === 1) {
+    const { command, args } = pathData[0];
+    return command + stringifyArgs(command, args);
+  }
+
+  const commands = [];
+  let prev = { ...pathData[0] };
+
+  // match leading moveto with following lineto
+  if (pathData[1].command === 'L') {
+    prev.command = 'M';
+  } else if (pathData[1].command === 'l') {
+    prev.command = 'm';
+  }
+
+  for (let i = 1; i < pathData.length; i++) {
+    const { command, args } = pathData[i];
+    if (
+      (prev.command === command &&
+        prev.command !== 'M' &&
+        prev.command !== 'm') ||
+      // combine matching moveto and lineto sequences
+      (prev.command === 'M' && command === 'L') ||
+      (prev.command === 'm' && command === 'l')
+    ) {
+      prev.args = [...prev.args, ...args];
+      if (i === pathData.length - 1) {
+        commands.push(prev.command + stringifyArgs(prev.command, prev.args));
+      }
+    } else {
+      commands.push(prev.command + stringifyArgs(prev.command, prev.args));
+
+      if (i === pathData.length - 1) {
+        commands.push(command + stringifyArgs(command, args));
+      } else {
+        prev = { command, args };
+      }
+    }
+  }
+
+  return commands.join('');
+}
+
+/**
+ * @param {string} command
+ * @param {number[]} args
+ */
+function stringifyArgs(command, args) {
+  let result = '';
+  let previous;
+
+  for (let i = 0; i < args.length; i++) {
+    const roundedStr = minifyNumber(args[i]);
+    if (i === 0 || args[i] < 0) {
+      // avoid space before first and negative numbers
+      result += roundedStr;
+    } else if (!Number.isInteger(previous) && !isDigit(roundedStr[0])) {
+      // remove space before decimal with zero whole
+      // only when previous number is also decimal
+      result += roundedStr;
+    } else {
+      result += ` ${roundedStr}`;
+    }
+    previous = args[i];
+  }
+
+  return result;
+}