Function BitMatrixParser

src/bmparser.js:26–203

(bitMatrix)

function BitMatrixParser(bitMatrix)
{
	var dimension = bitMatrix.Dimension;
	if (dimension < 21 || (dimension & 0x03) != 1)
	{
		throw "Error BitMatrixParser";
	}
	this.bitMatrix = bitMatrix;
	this.parsedVersion = null;
	this.parsedFormatInfo = null;
	
	this.copyBit=function( i,  j,  versionBits)
	{
		return this.bitMatrix.get_Renamed(i, j)?(versionBits << 1) | 0x1:versionBits << 1;
	}
	
	this.readFormatInformation=function()
	{
			if (this.parsedFormatInfo != null)
			{
				return this.parsedFormatInfo;
			}
			
			// Read top-left format info bits
			var formatInfoBits = 0;
			for (var i = 0; i < 6; i++)
			{
				formatInfoBits = this.copyBit(i, 8, formatInfoBits);
			}
			// .. and skip a bit in the timing pattern ...
			formatInfoBits = this.copyBit(7, 8, formatInfoBits);
			formatInfoBits = this.copyBit(8, 8, formatInfoBits);
			formatInfoBits = this.copyBit(8, 7, formatInfoBits);
			// .. and skip a bit in the timing pattern ...
			for (var j = 5; j >= 0; j--)
			{
				formatInfoBits = this.copyBit(8, j, formatInfoBits);
			}
			
			this.parsedFormatInfo = FormatInformation.decodeFormatInformation(formatInfoBits);
			if (this.parsedFormatInfo != null)
			{
				return this.parsedFormatInfo;
			}
			
			// Hmm, failed. Try the top-right/bottom-left pattern
			var dimension = this.bitMatrix.Dimension;
			formatInfoBits = 0;
			var iMin = dimension - 8;
			for (var i = dimension - 1; i >= iMin; i--)
			{
				formatInfoBits = this.copyBit(i, 8, formatInfoBits);
			}
			for (var j = dimension - 7; j < dimension; j++)
			{
				formatInfoBits = this.copyBit(8, j, formatInfoBits);
			}