add: crc32

Author: surunzi

DOC.md

@@ -2052,6 +2052,20 @@ CRC16 implementation.
 crc16('1234567890').toString(16); // -> 'c57a'
 ```
 
+## crc32 
+
+CRC32 implementation.
+
+|Name      |Type                                |Desc                 |
+|----------|------------------------------------|---------------------|
+|input     |string Buffer ArrayBuffer Uint8Array|Data to calculate    |
+|[previous]|number                              |Previous CRC32 result|
+|return    |number                              |CRC16 result         |
+
+```javascript
+crc32('1234567890').toString(16); // -> '261daee5'
+```
+
 ## crc8 
 
 CRC8 implementation.

DOC_CN.md

@@ -2047,6 +2047,20 @@ CRC16 算法实现。
 crc16('1234567890').toString(16); // -> 'c57a'
 ```
 
+## crc32
+
+CRC32 算法实现。 
+
+|参数名|类型|说明|
+|-----|----|---|
+|input|string Buffer ArrayBuffer Uint8Array|信息码|
+|[previous]|number|用于累积计算的 CRC32 校验码|
+|返回值|number|CRC32 校验码|
+
+```javascript
+crc32('1234567890').toString(16); // -> '261daee5'
+```
+
 ## crc8
 
 CRC8 算法实现。 

index.json

@@ -1256,6 +1256,21 @@
             "browser"
         ]
     },
+    "crc32": {
+        "description": "CRC32 implementation.",
+        "dependencies": [
+            "crc1"
+        ],
+        "env": [
+            "node",
+            "browser",
+            "miniprogram"
+        ],
+        "test": [
+            "node",
+            "browser"
+        ]
+    },
     "crc8": {
         "description": "CRC8 implementation.",
         "dependencies": [

src/c/crc32.i18n.md

@@ -0,0 +1,9 @@
+## CN
+
+CRC32 算法实现。 
+
+|参数名|类型|说明|
+|-----|----|---|
+|input|string Buffer ArrayBuffer Uint8Array|信息码|
+|[previous]|number|用于累积计算的 CRC32 校验码|
+|返回值|number|CRC32 校验码|

src/c/crc32.js

@@ -0,0 +1,59 @@
+/* CRC32 implementation.
+ *
+ * |Name      |Type                                |Desc                 |
+ * |----------|------------------------------------|---------------------|
+ * |input     |string Buffer ArrayBuffer Uint8Array|Data to calculate    |
+ * |[previous]|number                              |Previous CRC32 result|
+ * |return    |number                              |CRC16 result         |
+ */
+
+/* example
+ * crc32('1234567890').toString(16); // -> '261daee5'
+ */
+
+/* module
+ * env: all
+ * test: all
+ */
+
+/* typescript
+ * export declare function crc32(
+ *     input: string | Buffer | ArrayBuffer | Uint8Array,
+ *     previous?: number
+ * ): number;
+ */
+
+_('crc1');
+
+let TABLE = [];
+
+for (let n = 0; n < 256; n++) {
+    let c = n;
+    for (let k = 0; k < 8; k++) {
+        if (c & 1) {
+            c = 0xedb88320 ^ (c >>> 1);
+        } else {
+            c = c >>> 1;
+        }
+    }
+    TABLE[n] = c >>> 0;
+}
+
+if (typeof Int32Array !== 'undefined') TABLE = new Int32Array(TABLE);
+
+exports = function(input, previous) {
+    return exports.signed(input, previous) >>> 0;
+};
+
+exports.signed = function(input, previous) {
+    input = crc1.transInput(input);
+
+    let crc = previous === 0 ? 0 : ~~previous ^ -1;
+
+    for (let i = 0, len = input.length; i < len; i++) {
+        const byte = input[i];
+        crc = TABLE[(crc ^ byte) & 0xff] ^ (crc >>> 8);
+    }
+
+    return crc ^ -1;
+};

src/c/crc32.test.js

@@ -0,0 +1,3 @@
+it('basic', () => {
+    expect(crc32('1234567890').toString(16)).to.equal('261daee5');
+});