buffer: add indexOf() method

Add Buffer#indexOf(). Support strings, numbers and other Buffers. Also
included docs and tests.

Special thanks to Sam Rijs <[email protected]> for first proposing this
change.

PR-URL: #561
Reviewed-by: Ben Noordhuis <[email protected]>
Reviewed-By: Brian White <[email protected]>
Reviewed-By: Chris Dickinson <[email protected]>

doc/api/buffer.markdown

@@ -392,6 +392,19 @@ byte from the original Buffer.
     // abc
     // !bc
 
+
+### buf.indexOf(value[, byteOffset])
+
+* `value` String, Buffer or Number
+* `byteOffset` Number, Optional, Default: 0
+* Return: Number
+
+Operates similar to
+[Array#indexOf()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf).
+Accepts a String, Buffer or Number. Strings are interpreted as UTF8. Buffers
+will use the entire buffer. So in order to compare a partial Buffer use
+`Buffer#slice()`. Numbers can range from 0 to 255.
+
 ### buf.readUInt8(offset[, noAssert])
 
 * `offset` Number

lib/buffer.js

@@ -303,6 +303,24 @@ Buffer.prototype.compare = function compare(b) {
 };
 
 
+Buffer.prototype.indexOf = function indexOf(val, byteOffset) {
+  if (byteOffset > 0x7fffffff)
+    byteOffset = 0x7fffffff;
+  else if (byteOffset < -0x80000000)
+    byteOffset = -0x80000000;
+  byteOffset >>= 0;
+
+  if (typeof val === 'string')
+    return binding.indexOfString(this, val, byteOffset);
+  if (val instanceof Buffer)
+    return binding.indexOfBuffer(this, val, byteOffset);
+  if (typeof val === 'number')
+    return binding.indexOfNumber(this, val, byteOffset);
+
+  throw new TypeError('val must be string, number or Buffer');
+};
+
+
 Buffer.prototype.fill = function fill(val, start, end) {
   start = start >> 0;
   end = (end === undefined) ? this.length : end >> 0;

src/node_buffer.cc

@@ -602,6 +602,119 @@ void Compare(const FunctionCallbackInfo<Value> &args) {
 }
 
 
+int32_t IndexOf(const char* haystack,
+                size_t h_length,
+                const char* needle,
+                size_t n_length) {
+  CHECK_GE(h_length, n_length);
+  // TODO(trevnorris): Implement Boyer-Moore string search algorithm.
+  for (size_t i = 0; i < h_length - n_length + 1; i++) {
+    if (haystack[i] == needle[0]) {
+      if (memcmp(haystack + i, needle, n_length) == 0)
+        return i;
+    }
+  }
+  return -1;
+}
+
+
+void IndexOfString(const FunctionCallbackInfo<Value>& args) {
+  ASSERT(args[0]->IsObject());
+  ASSERT(args[1]->IsString());
+  ASSERT(args[2]->IsNumber());
+
+  ARGS_THIS(args[0].As<Object>());
+  node::Utf8Value str(args.GetIsolate(), args[1]);
+  int32_t offset_i32 = args[2]->Int32Value();
+  uint32_t offset;
+
+  if (offset_i32 < 0) {
+    if (offset_i32 + static_cast<int32_t>(obj_length) < 0)
+      offset = 0;
+    else
+      offset = static_cast<uint32_t>(obj_length + offset_i32);
+  } else {
+    offset = static_cast<uint32_t>(offset_i32);
+  }
+
+  if (str.length() == 0 ||
+      obj_length == 0 ||
+      (offset != 0 && str.length() + offset <= str.length()) ||
+      str.length() + offset > obj_length)
+    return args.GetReturnValue().Set(-1);
+
+  int32_t r =
+      IndexOf(obj_data + offset, obj_length - offset, *str, str.length());
+  args.GetReturnValue().Set(r == -1 ? -1 : static_cast<int32_t>(r + offset));
+}
+
+
+void IndexOfBuffer(const FunctionCallbackInfo<Value>& args) {
+  ASSERT(args[0]->IsObject());
+  ASSERT(args[1]->IsObject());
+  ASSERT(args[2]->IsNumber());
+
+  ARGS_THIS(args[0].As<Object>());
+  Local<Object> buf = args[1].As<Object>();
+  int32_t offset_i32 = args[2]->Int32Value();
+  size_t buf_length = buf->GetIndexedPropertiesExternalArrayDataLength();
+  char* buf_data =
+      static_cast<char*>(buf->GetIndexedPropertiesExternalArrayData());
+  uint32_t offset;
+
+  if (buf_length > 0)
+    CHECK_NE(buf_data, nullptr);
+
+  if (offset_i32 < 0) {
+    if (offset_i32 + static_cast<int32_t>(obj_length) < 0)
+      offset = 0;
+    else
+      offset = static_cast<uint32_t>(obj_length + offset_i32);
+  } else {
+    offset = static_cast<uint32_t>(offset_i32);
+  }
+
+  if (buf_length == 0 ||
+      obj_length == 0 ||
+      (offset != 0 && buf_length + offset <= buf_length) ||
+      buf_length + offset > obj_length)
+    return args.GetReturnValue().Set(-1);
+
+  int32_t r =
+    IndexOf(obj_data + offset, obj_length - offset, buf_data, buf_length);
+  args.GetReturnValue().Set(r == -1 ? -1 : static_cast<int32_t>(r + offset));
+}
+
+
+void IndexOfNumber(const FunctionCallbackInfo<Value>& args) {
+  ASSERT(args[0]->IsObject());
+  ASSERT(args[1]->IsNumber());
+  ASSERT(args[2]->IsNumber());
+
+  ARGS_THIS(args[0].As<Object>());
+  uint32_t needle = args[1]->Uint32Value();
+  int32_t offset_i32 = args[2]->Int32Value();
+  uint32_t offset;
+
+  if (offset_i32 < 0) {
+    if (offset_i32 + static_cast<int32_t>(obj_length) < 0)
+      offset = 0;
+    else
+      offset = static_cast<uint32_t>(obj_length + offset_i32);
+  } else {
+    offset = static_cast<uint32_t>(offset_i32);
+  }
+
+  if (obj_length == 0 || offset + 1 > obj_length)
+    return args.GetReturnValue().Set(-1);
+
+  void* ptr = memchr(obj_data + offset, needle, obj_length - offset);
+  char* ptr_char = static_cast<char*>(ptr);
+  args.GetReturnValue().Set(
+      ptr ? static_cast<int32_t>(ptr_char - obj_data) : -1);
+}
+
+
 // pass Buffer object to load prototype methods
 void SetupBufferJS(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
@@ -650,6 +763,9 @@ void Initialize(Handle<Object> target,
   env->SetMethod(target, "byteLength", ByteLength);
   env->SetMethod(target, "compare", Compare);
   env->SetMethod(target, "fill", Fill);
+  env->SetMethod(target, "indexOfBuffer", IndexOfBuffer);
+  env->SetMethod(target, "indexOfNumber", IndexOfNumber);
+  env->SetMethod(target, "indexOfString", IndexOfString);
 
   env->SetMethod(target, "readDoubleBE", ReadDoubleBE);
   env->SetMethod(target, "readDoubleLE", ReadDoubleLE);

test/parallel/test-buffer-indexof.js

@@ -0,0 +1,75 @@
+var common = require('../common');
+var assert = require('assert');
+
+var Buffer = require('buffer').Buffer;
+
+var b = new Buffer('abcdef');
+var buf_a = new Buffer('a');
+var buf_bc = new Buffer('bc');
+var buf_f = new Buffer('f');
+var buf_z = new Buffer('z');
+var buf_empty = new Buffer('');
+
+assert.equal(b.indexOf('a'), 0);
+assert.equal(b.indexOf('a', 1), -1);
+assert.equal(b.indexOf('a', -1), -1);
+assert.equal(b.indexOf('a', -4), -1);
+assert.equal(b.indexOf('a', -b.length), 0);
+assert.equal(b.indexOf('a', NaN), 0);
+assert.equal(b.indexOf('a', -Infinity), 0);
+assert.equal(b.indexOf('a', Infinity), -1);
+assert.equal(b.indexOf('bc'), 1);
+assert.equal(b.indexOf('bc', 2), -1);
+assert.equal(b.indexOf('bc', -1), -1);
+assert.equal(b.indexOf('bc', -3), -1);
+assert.equal(b.indexOf('bc', -5), 1);
+assert.equal(b.indexOf('bc', NaN), 1);
+assert.equal(b.indexOf('bc', -Infinity), 1);
+assert.equal(b.indexOf('bc', Infinity), -1);
+assert.equal(b.indexOf('f'), b.length - 1);
+assert.equal(b.indexOf('z'), -1);
+assert.equal(b.indexOf(''), -1);
+assert.equal(b.indexOf('', 1), -1);
+assert.equal(b.indexOf('', b.length + 1), -1);
+assert.equal(b.indexOf('', Infinity), -1);
+assert.equal(b.indexOf(buf_a), 0);
+assert.equal(b.indexOf(buf_a, 1), -1);
+assert.equal(b.indexOf(buf_a, -1), -1);
+assert.equal(b.indexOf(buf_a, -4), -1);
+assert.equal(b.indexOf(buf_a, -b.length), 0);
+assert.equal(b.indexOf(buf_a, NaN), 0);
+assert.equal(b.indexOf(buf_a, -Infinity), 0);
+assert.equal(b.indexOf(buf_a, Infinity), -1);
+assert.equal(b.indexOf(buf_bc), 1);
+assert.equal(b.indexOf(buf_bc, 2), -1);
+assert.equal(b.indexOf(buf_bc, -1), -1);
+assert.equal(b.indexOf(buf_bc, -3), -1);
+assert.equal(b.indexOf(buf_bc, -5), 1);
+assert.equal(b.indexOf(buf_bc, NaN), 1);
+assert.equal(b.indexOf(buf_bc, -Infinity), 1);
+assert.equal(b.indexOf(buf_bc, Infinity), -1);
+assert.equal(b.indexOf(buf_f), b.length - 1);
+assert.equal(b.indexOf(buf_z), -1);
+assert.equal(b.indexOf(buf_empty), -1);
+assert.equal(b.indexOf(buf_empty, 1), -1);
+assert.equal(b.indexOf(buf_empty, b.length + 1), -1);
+assert.equal(b.indexOf(buf_empty, Infinity), -1);
+assert.equal(b.indexOf(0x61), 0);
+assert.equal(b.indexOf(0x61, 1), -1);
+assert.equal(b.indexOf(0x61, -1), -1);
+assert.equal(b.indexOf(0x61, -4), -1);
+assert.equal(b.indexOf(0x61, -b.length), 0);
+assert.equal(b.indexOf(0x61, NaN), 0);
+assert.equal(b.indexOf(0x61, -Infinity), 0);
+assert.equal(b.indexOf(0x61, Infinity), -1);
+assert.equal(b.indexOf(0x0), -1);
+
+assert.throws(function() {
+  b.indexOf(function() { });
+});
+assert.throws(function() {
+  b.indexOf({});
+});
+assert.throws(function() {
+  b.indexOf([]);
+});