qrazybox/js/jsqrcode/datablock.js
2018-05-11 03:30:12 +07:00

117 lines
3.5 KiB
JavaScript

/*
Ported to JavaScript by Lazar Laszlo 2011
lazarsoft@gmail.com, www.lazarsoft.info
*/
/*
*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
function DataBlock(numDataCodewords, codewords)
{
this.numDataCodewords = numDataCodewords;
this.codewords = codewords;
this.__defineGetter__("NumDataCodewords", function()
{
return this.numDataCodewords;
});
this.__defineGetter__("Codewords", function()
{
return this.codewords;
});
}
DataBlock.getDataBlocks=function(rawCodewords, version, ecLevel)
{
if (rawCodewords.length != version.TotalCodewords)
{
throw "ArgumentException";
}
// Figure out the number and size of data blocks used by this version and
// error correction level
var ecBlocks = version.getECBlocksForLevel(ecLevel);
// First count the total number of data blocks
var totalBlocks = 0;
var ecBlockArray = ecBlocks.getECBlocks();
for (var i = 0; i < ecBlockArray.length; i++)
{
totalBlocks += ecBlockArray[i].Count;
}
// Now establish DataBlocks of the appropriate size and number of data codewords
var result = new Array(totalBlocks);
var numResultBlocks = 0;
for (var j = 0; j < ecBlockArray.length; j++)
{
var ecBlock = ecBlockArray[j];
for (var i = 0; i < ecBlock.Count; i++)
{
var numDataCodewords = ecBlock.DataCodewords;
var numBlockCodewords = ecBlocks.ECCodewordsPerBlock + numDataCodewords;
result[numResultBlocks++] = new DataBlock(numDataCodewords, new Array(numBlockCodewords));
}
}
// All blocks have the same amount of data, except that the last n
// (where n may be 0) have 1 more byte. Figure out where these start.
var shorterBlocksTotalCodewords = result[0].codewords.length;
var longerBlocksStartAt = result.length - 1;
while (longerBlocksStartAt >= 0)
{
var numCodewords = result[longerBlocksStartAt].codewords.length;
if (numCodewords == shorterBlocksTotalCodewords)
{
break;
}
longerBlocksStartAt--;
}
longerBlocksStartAt++;
var shorterBlocksNumDataCodewords = shorterBlocksTotalCodewords - ecBlocks.ECCodewordsPerBlock;
// The last elements of result may be 1 element longer;
// first fill out as many elements as all of them have
var rawCodewordsOffset = 0;
for (var i = 0; i < shorterBlocksNumDataCodewords; i++)
{
for (var j = 0; j < numResultBlocks; j++)
{
result[j].codewords[i] = rawCodewords[rawCodewordsOffset++];
}
}
// Fill out the last data block in the longer ones
for (var j = longerBlocksStartAt; j < numResultBlocks; j++)
{
result[j].codewords[shorterBlocksNumDataCodewords] = rawCodewords[rawCodewordsOffset++];
}
// Now add in error correction blocks
var max = result[0].codewords.length;
for (var i = shorterBlocksNumDataCodewords; i < max; i++)
{
for (var j = 0; j < numResultBlocks; j++)
{
var iOffset = j < longerBlocksStartAt?i:i + 1;
result[j].codewords[iOffset] = rawCodewords[rawCodewordsOffset++];
}
}
return result;
}