✨ feat: refactor huffman

Author: guanghechen

Diff for: MIGRATION.md

@@ -159,3 +159,10 @@ No breaking changes.
 ### @algorithm.ts/graph
 
 1. The graph related types is moved to `@algorithm.ts/types`.
+
+
+### @algorithm.ts/huffman
+
+1. `buildEncodingTable` is renamed to `toEncodingTable`.
+2. `buildHuffmanTree` is renamed to `fromEncodingTable`.
+3. `createHuffmanTree` is renamed to `fromText`.

Diff for: packages/huffman/README.md

@@ -1,6 +1,6 @@
 <header>
   <h1 align="center">
-    <a href="https://github.com/guanghechen/algorithm.ts/tree/release-2.x.x/packages/huffman#readme">@algorithm.ts/huffman</a>
+    <a href="https://github.com/guanghechen/algorithm.ts/tree/release-3.x.x/packages/huffman#readme">@algorithm.ts/huffman</a>
   </h1>
   <div align="center">
     <a href="https://www.npmjs.com/package/@algorithm.ts/huffman">
@@ -74,19 +74,18 @@ A typescript implementation of the **huffman** coding.
 
   ```typescript
   import { encode } from '@algorithm.ts/huffman'
-
   const { encodedData, encodingTable, tree } = encode('Hello, world!')
   ```
 
 * `decode`: Decode a huffman encoded data to string.
 
   ```typescript
-  import { decode } from '@algorithm.ts/huffman'
+  import { decode, fromEncodingTable } from '@algorithm.ts/huffman'
 
   const plaintext = decode(encodedData, tree)
 
   // Or build tree from encodingTable
-  const tree2 = buildHuffmanTree(encodingTable)
+  const tree2 = fromEncodingTable(encodingTable)
   const plaintext2 = decode(encodedData, tree2)
   ```
 
@@ -144,7 +143,7 @@ A typescript implementation of the **huffman** coding.
     const encodingTable = decompressEncodingTable(
       JSON.parse(textDecoder.decode(base64.decode(encodingTableText))),
     )
-    const tree = huffman.buildHuffmanTree(encodingTable)
+    const tree = huffman.fromEncodingTable(encodingTable)
 
     const cipherData = huffman.decompress(base64.decode(cipherText))
     const plaintext = huffman.decode(cipherData, tree)
@@ -181,4 +180,4 @@ A typescript implementation of the **huffman** coding.
 * [Huffman coding | Wikipedia](https://en.wikipedia.org/wiki/Huffman_coding)
 
 
-[homepage]: https://github.com/guanghechen/algorithm.ts/tree/release-2.x.x/packages/huffman#readme
+[homepage]: https://github.com/guanghechen/algorithm.ts/tree/release-3.x.x/packages/huffman#readme

Diff for: packages/huffman/__test__/huffman.spec.ts

@@ -1,4 +1,4 @@
-import { buildHuffmanTree, compress, decode, decompress, encode } from '../src'
+import { compress, decode, decompress, encode, fromEncodingTable } from '../src'
 
 describe('basic', function () {
   test('empty', () => textWrapper(''))
@@ -18,7 +18,7 @@ describe('basic', function () {
     const text2: string = decode(encodedData, tree)
     expect(text2).toEqual(text)
 
-    const tree2 = buildHuffmanTree(encodingTable)
+    const tree2 = fromEncodingTable(encodingTable)
     expect(tree).toEqual(tree2)
 
     expect(decode(encodedData, tree2)).toEqual(text)
@@ -32,9 +32,8 @@ describe('basic', function () {
 
 test('unexpected', function () {
   const { encodedData, encodingTable } = encode('Hello, world!')
-
   const { H, ...encodingTable2 } = encodingTable
-  const tree2 = buildHuffmanTree(encodingTable2)
+  const tree2 = fromEncodingTable(encodingTable2)
 
   expect(() => decode(encodedData, tree2)).toThrow(/Bad encoded data or huffman tree/)
 })

Diff for: packages/huffman/__test__/uri-compress.spec.ts

@@ -50,7 +50,7 @@ function decompress(compressedText: string): string {
   const encodingTable = decompressEncodingTable(
     JSON.parse(textDecoder.decode(base64.decode(encodingTableText))),
   )
-  const tree = huffman.buildHuffmanTree(encodingTable)
+  const tree = huffman.fromEncodingTable(encodingTable)
 
   const cipherData = huffman.decompress(base64.decode(cipherText))
   const plaintext = huffman.decode(cipherData, tree)

Diff for: packages/huffman/package.json

@@ -8,10 +8,10 @@
   },
   "repository": {
     "type": "git",
-    "url": "https://github.com/guanghechen/algorithm.ts/tree/release-2.x.x",
+    "url": "https://github.com/guanghechen/algorithm.ts/tree/release-3.x.x",
     "directory": "packages/huffman"
   },
-  "homepage": "https://github.com/guanghechen/algorithm.ts/tree/release-2.x.x/packages/huffman#readme",
+  "homepage": "https://github.com/guanghechen/algorithm.ts/tree/release-3.x.x/packages/huffman#readme",
   "keywords": [
     "algorithm",
     "huffman",

Diff for: packages/huffman/src/encode.ts

@@ -1,4 +1,4 @@
-import { buildEncodingTable, createHuffmanTree } from './huffman'
+import { fromText, toEncodingTable } from './huffman'
 import type { IHuffmanEncodedData, IHuffmanEncodingTable, IHuffmanNode } from './huffman'
 
 /**
@@ -11,9 +11,9 @@ export function encode(plaintext: string): {
   encodingTable: IHuffmanEncodingTable
   tree: IHuffmanNode
 } {
-  const tree: IHuffmanNode = createHuffmanTree(plaintext)
+  const tree: IHuffmanNode = fromText(plaintext)
   const encodedData: Array<0 | 1> = []
-  const encodingTable: IHuffmanEncodingTable = buildEncodingTable(tree)
+  const encodingTable: IHuffmanEncodingTable = toEncodingTable(tree)
   for (const c of plaintext) {
     // Invariant: data should not be null / undefined.
     const data: IHuffmanEncodedData = encodingTable[c]

Diff for: packages/huffman/src/huffman.ts

@@ -1,4 +1,4 @@
-import { createPriorityQueue } from '@algorithm.ts/priority-queue'
+import { PriorityQueue } from '@algorithm.ts/queue'
 
 export interface IHuffmanNode {
   value?: string
@@ -11,9 +11,11 @@ export type IHuffmanEncodedData = Array<0 | 1>
 export type IHuffmanEncodingTable = Record<string, IHuffmanEncodedData>
 
 /**
- * Create a Huffman tree for the specified texts.
+ * Create a Huffman tree from the specified text.
+ * @param text
+ * @returns
  */
-export function createHuffmanTree(text: string): IHuffmanNode {
+export function fromText(text: string): IHuffmanNode {
   const costMap: Record<string, number> = {}
   for (const c of text) {
     const cnt: number = costMap[c] ?? 0
@@ -23,55 +25,30 @@ export function createHuffmanTree(text: string): IHuffmanNode {
   const entries = Object.entries(costMap)
   if (entries.length <= 0) return {}
 
-  const priorityQueue = createPriorityQueue<{
+  const minHeap = new PriorityQueue<{
     cost: number
     node: IHuffmanNode
-  }>((x, y) => y.cost - x.cost)
-  priorityQueue.init(entries.map(([value, cost]) => ({ cost, node: { value } })))
-  while (priorityQueue.size() > 1) {
-    const o1 = priorityQueue.dequeue()!
-    const o2 = priorityQueue.dequeue()!
+  }>({ compare: (x, y) => x.cost - y.cost })
+  minHeap.init(entries.map(([value, cost]) => ({ cost, node: { value } })))
+
+  while (minHeap.size > 1) {
+    const o1 = minHeap.dequeue()!
+    const o2 = minHeap.dequeue()!
     const o: IHuffmanNode = { left: o1.node, right: o2.node }
-    priorityQueue.enqueue({
+    minHeap.enqueue({
       cost: o1.cost + o2.cost,
       node: o,
     })
   }
-  return priorityQueue.top()!.node
-}
-
-/**
- * Build a HuffmanEncodingTable based on Huffman tree.
- * @param tree
- * @returns
- */
-export function buildEncodingTable(tree: IHuffmanNode): IHuffmanEncodingTable {
-  const prefix: IHuffmanEncodedData = []
-  const encodingTable: IHuffmanEncodingTable = {}
-  collect(tree, 0)
-  return encodingTable
-
-  function collect(node: IHuffmanNode, cur: number): void {
-    if (node.value) encodingTable[node.value] = prefix.slice(0, cur)
-    else {
-      if (node.left) {
-        prefix[cur] = 0
-        collect(node.left, cur + 1)
-      }
-      if (node.right) {
-        prefix[cur] = 1
-        collect(node.right, cur + 1)
-      }
-    }
-  }
+  return minHeap.front()!.node
 }
 
 /**
  * Build a huffman tree based on HuffmanEncodingTable.
  * @param table
  * @returns
  */
-export function buildHuffmanTree(table: IHuffmanEncodingTable): IHuffmanNode {
+export function fromEncodingTable(table: IHuffmanEncodingTable): IHuffmanNode {
   const entries = Object.entries(table)
   if (entries.length === 0) return {}
 
@@ -91,3 +68,29 @@ export function buildHuffmanTree(table: IHuffmanEncodingTable): IHuffmanNode {
   }
   return root
 }
+
+/**
+ * Build a HuffmanEncodingTable based on Huffman tree.
+ * @param tree
+ * @returns
+ */
+export function toEncodingTable(tree: IHuffmanNode): IHuffmanEncodingTable {
+  const prefix: IHuffmanEncodedData = []
+  const encodingTable: IHuffmanEncodingTable = {}
+  collect(tree, 0)
+  return encodingTable
+
+  function collect(node: IHuffmanNode, cur: number): void {
+    if (node.value) encodingTable[node.value] = prefix.slice(0, cur)
+    else {
+      if (node.left) {
+        prefix[cur] = 0
+        collect(node.left, cur + 1)
+      }
+      if (node.right) {
+        prefix[cur] = 1
+        collect(node.right, cur + 1)
+      }
+    }
+  }
+}

Diff for: packages/huffman/src/index.ts

@@ -1,6 +1,6 @@
 import { compress, decompress } from './compress'
 import { decode, encode } from './encode'
-import { buildEncodingTable, buildHuffmanTree, createHuffmanTree } from './huffman'
+import { fromEncodingTable, fromText, toEncodingTable } from './huffman'
 
 export * from './compress'
 export * from './encode'
@@ -11,7 +11,7 @@ export default {
   decode,
   compress,
   decompress,
-  buildEncodingTable,
-  createHuffmanTree,
-  buildHuffmanTree,
+  fromText,
+  fromEncodingTable,
+  toEncodingTable,
 }