初始化

uni_modules/UniDevTools/node_modules/pngjs/lib/crc.js

@@ -0,0 +1,44 @@
+'use strict';
+
+var crcTable = [];
+
+(function() {
+  for (var i = 0; i < 256; i++) {
+    var currentCrc = i;
+    for (var j = 0; j < 8; j++) {
+      if (currentCrc & 1) {
+        currentCrc = 0xedb88320 ^ (currentCrc >>> 1);
+      }
+      else {
+        currentCrc = currentCrc >>> 1;
+      }
+    }
+    crcTable[i] = currentCrc;
+  }
+}());
+
+var CrcCalculator = module.exports = function() {
+  this._crc = -1;
+};
+
+CrcCalculator.prototype.write = function(data) {
+
+  for (var i = 0; i < data.length; i++) {
+    this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
+  }
+  return true;
+};
+
+CrcCalculator.prototype.crc32 = function() {
+  return this._crc ^ -1;
+};
+
+
+CrcCalculator.crc32 = function(buf) {
+
+  var crc = -1;
+  for (var i = 0; i < buf.length; i++) {
+    crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
+  }
+  return crc ^ -1;
+};