实现utf8解码

Author: modood

utf8_decode.js

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+/**
+ * @description 实现utf8解码
+ * @author 未知
+ */
+
+function utf8_decode(str_data){
+    var tmp_arr = [],i = 0,ac = 0,c1 = 0,c2 = 0,c3 = 0;str_data += '';
+    while (i < str_data.length) {
+            c1 = str_data.charCodeAt(i);
+            if (c1 < 128) {
+                    tmp_arr[ac++] = String.fromCharCode(c1);
+                    i++;
+            } else if (c1 > 191 && c1 < 224) {       
+                    c2 = str_data.charCodeAt(i + 1);
+                    tmp_arr[ac++] = String.fromCharCode(((c1 & 31) << 6) | (c2 & 63));
+                    i += 2;
+            } else {
+                    c2 = str_data.charCodeAt(i + 1);
+                    c3 = str_data.charCodeAt(i + 2);
+                    tmp_arr[ac++] = String.fromCharCode(((c1 & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
+                    i += 3;
+            }
+    } 
+    return tmp_arr.join('');
+}