feat: support get raw string by string length (#30)

Author: dead-horse

benchmark/get.js

@@ -143,6 +143,9 @@ suite
 .add('getRawString(0, 100)', function () {
   putRawStringBytes.getRawString(0, 100);
 })
+.add('getRawStringByStringLength(0, 100)', function () {
+  putRawStringBytes.getRawStringByStringLength(0, 100);
+})
 
 .on('cycle', function(event) {
   benchmarks.add(event.target);
@@ -155,22 +158,31 @@ suite
 })
 .run({ 'async': false });
 
-// node version: v0.11.12, date: Mon May 12 2014 19:14:26 GMT+0800 (CST)
+// node version: v8.9.0, date: Thu Nov 16 2017 12:27:51 GMT+0800 (CST)
 // Starting...
-// 15 tests completed.
-
-// get(0, 1) => copy Buffer    x  2,059,464 ops/sec ±9.18% (69 runs sampled)
-// get(0, 100) => copy Buffer  x  2,124,455 ops/sec ±4.98% (75 runs sampled)
-// get(0, 4096) => copy Buffer x    356,927 ops/sec ±9.43% (56 runs sampled)
-// get() => byte               x 15,477,897 ops/sec ±3.05% (89 runs sampled)
-// getChar(0)                  x 52,541,591 ops/sec ±1.04% (95 runs sampled)
-// getShort(0)                 x 26,297,086 ops/sec ±2.46% (89 runs sampled)
-// getInt(0)                   x 18,772,003 ops/sec ±6.27% (71 runs sampled)
-// getFloat(0)                 x 13,132,298 ops/sec ±1.68% (97 runs sampled)
-// getDouble(0)                x 10,968,594 ops/sec ±1.27% (94 runs sampled)
-// getLong(0)                  x 11,849,374 ops/sec ±2.63% (96 runs sampled)
-// getString(0)                x  2,358,382 ops/sec ±5.78% (76 runs sampled)
-// getCString(0)               x  1,618,356 ops/sec ±8.41% (72 runs sampled)
-// readRawString(4, 100)       x  4,790,991 ops/sec ±9.25% (79 runs sampled)
-// readRawString(100)          x  5,434,663 ops/sec ±1.32% (95 runs sampled)
-// getRawString(0, 100)        x  5,497,325 ops/sec ±1.02% (98 runs sampled)
+// 24 tests completed.
+//
+// _offset = 0                        x 1,313,398,169 ops/sec ±1.69% (92 runs sampled)
+// position(0)                        x   154,052,896 ops/sec ±1.90% (91 runs sampled)
+// position()                         x   234,018,744 ops/sec ±12.30% (91 runs sampled)
+// _bytes.copy(0, 1)                  x     1,359,434 ops/sec ±1.75% (89 runs sampled)
+// get(0, 1) => copy Buffer           x     1,318,288 ops/sec ±2.01% (86 runs sampled)
+// get(0, 100) => copy Buffer         x     1,122,101 ops/sec ±1.07% (77 runs sampled)
+// get(0, 4096) => copy Buffer        x       360,451 ops/sec ±3.04% (84 runs sampled)
+// _bytes[i]                          x   668,005,958 ops/sec ±1.15% (94 runs sampled)
+// get() => byte                      x   139,503,339 ops/sec ±0.94% (92 runs sampled)
+// get(0) => byte                     x   145,565,421 ops/sec ±0.88% (94 runs sampled)
+// getChar(0)                         x   146,359,082 ops/sec ±0.90% (94 runs sampled)
+// _bytes.readUInt16BE                x   135,816,353 ops/sec ±0.97% (93 runs sampled)
+// getShort(0)                        x   122,965,917 ops/sec ±1.09% (93 runs sampled)
+// getShort()                         x   118,434,346 ops/sec ±0.93% (90 runs sampled)
+// getInt(0)                          x    23,725,763 ops/sec ±1.15% (91 runs sampled)
+// getFloat(0)                        x    10,082,681 ops/sec ±0.95% (93 runs sampled)
+// getDouble(0)                       x     9,406,714 ops/sec ±2.16% (92 runs sampled)
+// getLong(0)                         x    62,055,693 ops/sec ±1.69% (92 runs sampled)
+// getString(0)                       x     5,086,919 ops/sec ±1.53% (93 runs sampled)
+// getCString(0)                      x     5,088,544 ops/sec ±1.07% (91 runs sampled)
+// readRawString(4, 100)              x     6,293,722 ops/sec ±1.12% (90 runs sampled)
+// readRawString(100)                 x     6,189,186 ops/sec ±1.02% (90 runs sampled)
+// getRawString(0, 100)               x     1,232,435 ops/sec ±1.23% (89 runs sampled)
+// getRawStringByStringLength(0, 100) x     1,203,666 ops/sec ±1.34% (94 runs sampled)

lib/byte.js

@@ -405,6 +405,41 @@ ByteBuffer.prototype._copy = function (start, end) {
   return buf;
 };
 
+ByteBuffer.prototype.getRawStringByStringLength = function (index, length) {
+  var needUpdateOffset = false;
+  if (arguments.length === 1) {
+    length = index;
+    index = this._offset;
+    needUpdateOffset = true;
+  }
+
+  var data = [];
+  var bufLength = 0;
+  while (length--) {
+    var pos = index + bufLength;
+    var ch = this._bytes[pos];
+    if (ch < 0x80) {
+      data.push(ch);
+      bufLength += 1;
+    } else if ((ch & 0xe0) === 0xc0) {
+      var ch1 = this._bytes[++pos];
+      var v = ((ch & 0x1f) << 6) + (ch1 & 0x3f);
+      data.push(v);
+      bufLength += 2;
+    } else if ((ch & 0xf0) === 0xe0) {
+      var ch1 = this._bytes[++pos];
+      var ch2 = this._bytes[++pos];
+      var v = ((ch & 0x0f) << 12) + ((ch1 & 0x3f) << 6) + (ch2 & 0x3f);
+      data.push(v);
+      bufLength += 3;
+    } else {
+      throw new Error('string is not valid UTF-8 encode');
+    }
+  }
+  if (needUpdateOffset) this._offset += bufLength;
+  return String.fromCharCode.apply(String, data);
+};
+
 ByteBuffer.prototype.getRawString = function (index, length) {
   if (typeof index !== 'number') {
     // getRawString() => current offset char string

package.json

@@ -30,7 +30,7 @@
     "intelli-espower-loader": "^1.0.1",
     "istanbul": "*",
     "jshint": "*",
-    "mocha": "*",
+    "mocha": "3",
     "optimized": "^1.2.0",
     "power-assert": "^1.4.4"
   },
@@ -56,4 +56,4 @@
   },
   "author": "fengmk2 <[email protected]> (http://fengmk2.com)",
   "license": "MIT"
-}
+}

test/byte.test.js

@@ -465,17 +465,20 @@ describe('byte.test.js', function () {
       bytes.putRawString(' world');
       assert(bytes.toString() === '<ByteBuffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>');
       assert(bytes.getRawString(0, 11) === 'hello world');
+      assert(bytes.getRawStringByStringLength(0, 11) === 'hello world');
       bytes.position(0);
       assert(bytes.getRawString() === 'h');
 
       bytes = ByteBuffer.allocate(1);
       bytes.putRawString('你好');
       assert(bytes.toString() === '<ByteBuffer e4 bd a0 e5 a5 bd>');
       assert(bytes.position(0).readRawString(6) === '你好');
+      assert(bytes.position(0).getRawString(0, 6) === '你好');
+      assert(bytes.position(0).getRawStringByStringLength(2) === '你好');
       bytes.putRawString(0, '我们');
       assert(bytes.toString() === '<ByteBuffer e6 88 91 e4 bb ac>');
       assert(bytes.getRawString(0, 6) === '我们');
-
+      assert(bytes.getRawStringByStringLength(0, 2) === '我们');
       assert(bytes.readRawString(0, 6) === '我们');
 
       bytes = ByteBuffer.allocate(1);
@@ -633,19 +636,22 @@ describe('byte.test.js', function () {
       bytes.putRawString(str);
       assert(bytes.toString() === '<ByteBuffer 68 65 6c 6c 6f e9 a6 83 e5 b0 b2>');
       assert.deepEqual(bytes.getRawString(0, 11), str);
+      assert.deepEqual(bytes.getRawStringByStringLength(0, 7), str);
       // gbk
       var bytes = ByteBuffer.allocate(1);
       var str = 'hello\ud83c\udf3c';
       bytes.putRawString(str);
       assert(bytes.toString() === '<ByteBuffer 68 65 6c 6c 6f ed a0 bc ed bc bc>');
       assert.deepEqual(bytes.getRawString(0, 11), str);
+      assert.deepEqual(bytes.getRawStringByStringLength(0, 7), str);
 
       var bytes = ByteBuffer.allocate(1);
       // java encode bytes: [-19, -96, -67, -19, -72, -128, 87, 119, 119, -23, -126, -93]
       var str = '\ud83d\ude00Www那';
       bytes.putRawString(str);
       assert(bytes.toString() === '<ByteBuffer ed a0 bd ed b8 80 57 77 77 e9 82 a3>');
       assert.deepEqual(bytes.getRawString(0, 12), str);
+      assert.deepEqual(bytes.getRawStringByStringLength(0, 6), str);
 
       // Construction of a special test case which triggers the bug
       // of allocating insufficient space via _checkSize
@@ -766,4 +772,28 @@ describe('byte.test.js', function () {
      assert.deepEqual(buf, new Buffer([0, 0, 0, 5]));
    });
   });
+
+  describe('getRawStringByStringLength()', function () {
+    it('should get with mixed sting success', function () {
+      var bytes = ByteBuffer.allocate(1000);
+      var str = '你好啊,1234,abcde,\ud83d\ude00Www那';
+      bytes.putRawString(str);
+      var pos = bytes.position();
+      bytes.position(0);
+      assert(str === bytes.getRawStringByStringLength(0, str.length));
+      assert(bytes.position() === 0);
+      assert(str === bytes.getRawStringByStringLength(str.length));
+      assert(bytes.position() === pos);
+    });
+
+    it('should throw if encode error', function () {
+      var bytes = ByteBuffer.allocate(1000);
+      var str = '你好啊,1234,abcde,\ud83d\ude00Www那';
+      bytes.putRawString(str);
+      bytes.put(0xfd);
+      assert.throws(function () {
+        bytes.getRawStringByStringLength(0, str.length + 1);
+      }, 'string is not valid UTF-8 encode');
+    });
+  });
 });