Buffer, feat: Buffer.from support byteOffset and length.

fibjs · Aug 13, 2017 · 4240334 · 4240334
1 parent cd5ca14
commit 4240334
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Showing 4 changed files with 49 additions and 60 deletions.
diff --git a/fibjs/include/ifs/Buffer.h b/fibjs/include/ifs/Buffer.h
@@ -30,10 +30,8 @@ class Buffer_base : public object_base {
     static result_t _new(exlib::string str, exlib::string codec, obj_ptr<Buffer_base>& retVal, v8::Local<v8::Object> This = v8::Local<v8::Object>());
     static result_t _new(int32_t size, obj_ptr<Buffer_base>& retVal, v8::Local<v8::Object> This = v8::Local<v8::Object>());
     static result_t isBuffer(v8::Local<v8::Value> v, bool& retVal);
-    static result_t from(v8::Local<v8::Array> datas, obj_ptr<Buffer_base>& retVal);
-    static result_t from(v8::Local<v8::ArrayBuffer> datas, obj_ptr<Buffer_base>& retVal);
-    static result_t from(v8::Local<v8::TypedArray> datas, obj_ptr<Buffer_base>& retVal);
-    static result_t from(Buffer_base* buffer, obj_ptr<Buffer_base>& retVal);
+    static result_t from(Buffer_base* buffer, int32_t byteOffset, int32_t length, obj_ptr<Buffer_base>& retVal);
+    static result_t from(exlib::string str, int32_t byteOffset, int32_t length, obj_ptr<Buffer_base>& retVal);
     static result_t from(exlib::string str, exlib::string codec, obj_ptr<Buffer_base>& retVal);
     static result_t concat(v8::Local<v8::Array> buflist, int32_t cutLength, obj_ptr<Buffer_base>& retVal);
     static result_t alloc(int32_t size, int32_t fill, exlib::string codec, obj_ptr<Buffer_base>& retVal);
@@ -352,29 +350,21 @@ inline void Buffer_base::s_from(const v8::FunctionCallbackInfo<v8::Value>& args)
 
     METHOD_ENTER();
 
-    METHOD_OVER(1, 1);
-
-    ARG(v8::Local<v8::Array>, 0);
-
-    hr = from(v0, vr);
-
-    METHOD_OVER(1, 1);
-
-    ARG(v8::Local<v8::ArrayBuffer>, 0);
-
-    hr = from(v0, vr);
-
-    METHOD_OVER(1, 1);
+    METHOD_OVER(3, 1);
 
-    ARG(v8::Local<v8::TypedArray>, 0);
+    ARG(obj_ptr<Buffer_base>, 0);
+    OPT_ARG(int32_t, 1, 0);
+    OPT_ARG(int32_t, 2, -1);
 
-    hr = from(v0, vr);
+    hr = from(v0, v1, v2, vr);
 
-    METHOD_OVER(1, 1);
+    METHOD_OVER(3, 1);
 
-    ARG(obj_ptr<Buffer_base>, 0);
+    ARG(exlib::string, 0);
+    OPT_ARG(int32_t, 1, 0);
+    OPT_ARG(int32_t, 2, -1);
 
-    hr = from(v0, vr);
+    hr = from(v0, v1, v2, vr);
 
     METHOD_OVER(2, 1);
 

diff --git a/fibjs/src/global/Buffer.cpp b/fibjs/src/global/Buffer.cpp
@@ -91,34 +91,28 @@ result_t Buffer_base::isBuffer(v8::Local<v8::Value> v, bool& retVal)
     return 0;
 }
 
-result_t Buffer_base::from(v8::Local<v8::Array> datas,
+result_t Buffer_base::from(Buffer_base* buffer, int32_t byteOffset, int32_t length,
     obj_ptr<Buffer_base>& retVal)
 {
-    retVal = new Buffer();
-    retVal->append(datas);
-    return 0;
+    exlib::string str;
+    buffer->toString(str);
+    return from(str, byteOffset, length, retVal);
 }
 
-result_t Buffer_base::from(v8::Local<v8::ArrayBuffer> datas,
+result_t Buffer_base::from(exlib::string str, int32_t byteOffset, int32_t length,
     obj_ptr<Buffer_base>& retVal)
 {
-    retVal = new Buffer();
-    retVal->append(datas);
-    return 0;
-}
+    if (byteOffset < 0)
+        return CHECK_ERROR(CALL_E_INVALIDARG);
 
-result_t Buffer_base::from(v8::Local<v8::TypedArray> datas,
-    obj_ptr<Buffer_base>& retVal)
-{
-    retVal = new Buffer();
-    return retVal->append(datas);
-}
+    if (byteOffset > str.length())
+        byteOffset = str.length();
 
-result_t Buffer_base::from(Buffer_base* buffer,
-    obj_ptr<Buffer_base>& retVal)
-{
-    retVal = new Buffer();
-    return retVal->append(buffer);
+    if (length < 0)
+        length = str.length() - byteOffset;
+
+    retVal = new Buffer(str.substr(byteOffset, length));
+    return 0;
 }
 
 result_t Buffer_base::from(exlib::string str, exlib::string codec,

diff --git a/idl/zh-cn/Buffer.idl b/idl/zh-cn/Buffer.idl
@@ -45,29 +45,21 @@ interface Buffer : object
     */
     static Boolean isBuffer(Value v);
 
-    /*! @brief 通过数组创建 Buffer 对象
-     @param datas 给定数组类型变量用于创建 Buffer 对象
-     @return 返回 Buffer 实例
-     */
-    static Buffer from(Array datas);
-
-    /*! @brief 通过 ArrayBuffer 创建 Buffer 对象
-     @param datas 给定 ArrayBuffer 类型变量用于创建 Buffer 对象
-     @return 返回 Buffer 实例
-     */
-    static Buffer from(ArrayBuffer datas);
-
-    /*! @brief 通过 TypedArray 创建 Buffer 对象
-     @param datas 给定 TypedArray 类型变量用于创建 Buffer 对象
+    /*! @brief 通过其他 Buffer 创建 Buffer 对象
+     @param buffer 给定 Buffer 类型变量用于创建 Buffer 对象
+     @param byteOffset 指定数据起始位置，起始为 0
+     @param length 指定数据长度，起始位 -1，表示剩余所有数据
      @return 返回 Buffer 实例
      */
-    static Buffer from(TypedArray datas);
+    static Buffer from(Buffer buffer, Integer byteOffset = 0, Integer length = -1);
 
-    /*! @brief 通过其他 Buffer 创建 Buffer 对象
-     @param buffer 给定 Buffer 类型变量用于创建 Buffer 对象
+    /*! @brief 通过字符串创建 Buffer 对象
+     @param str 初始化字符串，字符串将以 utf-8 格式写入
+     @param byteOffset 指定数据起始位置，起始为 0
+     @param length 指定数据长度，起始位 -1，表示剩余所有数据
      @return 返回 Buffer 实例
      */
-    static Buffer from(Buffer buffer);
+    static Buffer from(String str, Integer byteOffset = 0, Integer length = -1);
 
     /*! @brief 通过字符串创建 Buffer 对象
      @param str 初始化字符串，字符串将以 utf-8 格式写入，缺省则创建一个空对象

diff --git a/test/buffer_test.js b/test/buffer_test.js
@@ -156,6 +156,19 @@ describe('Buffer', () => {
         assert.equal(buf.toString(), "abcd");
     });
 
+    it('Buffer.from(Buffer, offset, len)', () => {
+        var buf = Buffer.from(new Buffer("abcd"), 1, 2);
+        assert.equal(buf.length, 2);
+        assert.equal(buf.toString(), "bc");
+
+        var buf = Buffer.from(new Buffer("abcd"), 1);
+        assert.equal(buf.length, 3);
+        assert.equal(buf.toString(), "bcd");
+
+        var buf = Buffer.from(new Buffer("abcd"), 10);
+        assert.equal(buf.length, 0);
+    });
+
     it('Buffer.byteLength(String)', () => {
         var str1 = "\u00bd + \u00bc = \u00be";
         var str2 = "0xffffff";