buffer: add indexOf() method

Add Buffer#indexOf(). Support strings, numbers and other Buffers.

Supported in iojs@1.5.0, see:
https://github.com/iojs/io.js/commit/f212ae702e57f6d6548972e10d4374a000e
53e19

diff --git a/index.js b/index.js
index e859ac344bb652bfcba39197c471cdec788755e4..8ef7e82500e5fe932f3813c05b7537d7bb70c5c5 100644 (file)
--- a/index.js
+++ b/index.js
@@ -308,6 +308,47 @@ Buffer.prototype.compare = function compare (b) {
   return Buffer.compare(this, b)
 }
 
+Buffer.prototype.indexOf = function indexOf (val, byteOffset) {
+  if (byteOffset > 0x7fffffff) byteOffset = 0x7fffffff
+  else if (byteOffset < -0x80000000) byteOffset = -0x80000000
+  byteOffset >>= 0
+
+  if (this.length === 0) return -1
+  if (byteOffset >= this.length) return -1
+
+  // Negative offsets start from the end of the buffer
+  if (byteOffset < 0) byteOffset = Math.max(this.length + byteOffset, 0)
+
+  if (typeof val === 'string') {
+    if (val.length === 0) return -1 // special case: looking for empty string always fails
+    return String.prototype.indexOf.call(this, val, byteOffset)
+  }
+  if (Buffer.isBuffer(val)) {
+    return arrayIndexOf(this, val, byteOffset)
+  }
+  if (typeof val === 'number') {
+    if (Buffer.TYPED_ARRAY_SUPPORT && Uint8Array.prototype.indexOf === 'function') {
+      return Uint8Array.prototype.indexOf.call(this, val, byteOffset)
+    }
+    return arrayIndexOf(this, [ val ], byteOffset)
+  }
+
+  function arrayIndexOf (arr, val, byteOffset) {
+    var foundIndex = -1
+    for (var i = 0; byteOffset + i < arr.length; i++) {
+      if (arr[byteOffset + i] === val[foundIndex === -1 ? 0 : i - foundIndex]) {
+        if (foundIndex === -1) foundIndex = i
+        if (i - foundIndex + 1 === val.length) return byteOffset + foundIndex
+      } else {
+        foundIndex = -1
+      }
+    }
+    return -1
+  }
+
+  throw new TypeError('val must be string, number or Buffer')
+}
+
 // `get` will be removed in Node 0.13+
 Buffer.prototype.get = function get (offset) {
   console.log('.get() is deprecated. Access using array indexes instead.')
@@ -1092,6 +1133,7 @@ Buffer._augment = function _augment (arr) {
   arr.toJSON = BP.toJSON
   arr.equals = BP.equals
   arr.compare = BP.compare
+  arr.indexOf = BP.indexOf
   arr.copy = BP.copy
   arr.slice = BP.slice
   arr.readUIntLE = BP.readUIntLE