feat: init

node_modules/undici/lib/core/tree.js

@@ -0,0 +1,152 @@
+'use strict'
+
+const {
+  wellknownHeaderNames,
+  headerNameLowerCasedRecord
+} = require('./constants')
+
+class TstNode {
+  /** @type {any} */
+  value = null
+  /** @type {null | TstNode} */
+  left = null
+  /** @type {null | TstNode} */
+  middle = null
+  /** @type {null | TstNode} */
+  right = null
+  /** @type {number} */
+  code
+  /**
+   * @param {string} key
+   * @param {any} value
+   * @param {number} index
+   */
+  constructor (key, value, index) {
+    if (index === undefined || index >= key.length) {
+      throw new TypeError('Unreachable')
+    }
+    const code = this.code = key.charCodeAt(index)
+    // check code is ascii string
+    if (code > 0x7F) {
+      throw new TypeError('key must be ascii string')
+    }
+    if (key.length !== ++index) {
+      this.middle = new TstNode(key, value, index)
+    } else {
+      this.value = value
+    }
+  }
+
+  /**
+   * @param {string} key
+   * @param {any} value
+   */
+  add (key, value) {
+    const length = key.length
+    if (length === 0) {
+      throw new TypeError('Unreachable')
+    }
+    let index = 0
+    let node = this
+    while (true) {
+      const code = key.charCodeAt(index)
+      // check code is ascii string
+      if (code > 0x7F) {
+        throw new TypeError('key must be ascii string')
+      }
+      if (node.code === code) {
+        if (length === ++index) {
+          node.value = value
+          break
+        } else if (node.middle !== null) {
+          node = node.middle
+        } else {
+          node.middle = new TstNode(key, value, index)
+          break
+        }
+      } else if (node.code < code) {
+        if (node.left !== null) {
+          node = node.left
+        } else {
+          node.left = new TstNode(key, value, index)
+          break
+        }
+      } else if (node.right !== null) {
+        node = node.right
+      } else {
+        node.right = new TstNode(key, value, index)
+        break
+      }
+    }
+  }
+
+  /**
+   * @param {Uint8Array} key
+   * @return {TstNode | null}
+   */
+  search (key) {
+    const keylength = key.length
+    let index = 0
+    let node = this
+    while (node !== null && index < keylength) {
+      let code = key[index]
+      // A-Z
+      // First check if it is bigger than 0x5a.
+      // Lowercase letters have higher char codes than uppercase ones.
+      // Also we assume that headers will mostly contain lowercase characters.
+      if (code <= 0x5a && code >= 0x41) {
+        // Lowercase for uppercase.
+        code |= 32
+      }
+      while (node !== null) {
+        if (code === node.code) {
+          if (keylength === ++index) {
+            // Returns Node since it is the last key.
+            return node
+          }
+          node = node.middle
+          break
+        }
+        node = node.code < code ? node.left : node.right
+      }
+    }
+    return null
+  }
+}
+
+class TernarySearchTree {
+  /** @type {TstNode | null} */
+  node = null
+
+  /**
+   * @param {string} key
+   * @param {any} value
+   * */
+  insert (key, value) {
+    if (this.node === null) {
+      this.node = new TstNode(key, value, 0)
+    } else {
+      this.node.add(key, value)
+    }
+  }
+
+  /**
+   * @param {Uint8Array} key
+   * @return {any}
+   */
+  lookup (key) {
+    return this.node?.search(key)?.value ?? null
+  }
+}
+
+const tree = new TernarySearchTree()
+
+for (let i = 0; i < wellknownHeaderNames.length; ++i) {
+  const key = headerNameLowerCasedRecord[wellknownHeaderNames[i]]
+  tree.insert(key, key)
+}
+
+module.exports = {
+  TernarySearchTree,
+  tree
+}