internal static Version DecodeVersionInformation(int versionBits)
{
int bestDifference = Int32.MaxValue;
int bestVersion = 0;
for (int i = 0; i < VERSION_DECODE_INFO.Length; i++)
{
int targetVersion = VERSION_DECODE_INFO[i];
// Do the version info bits match exactly? done.
if (targetVersion == versionBits)
{
return(GetVersionForNumber(i + 7));
}
// Otherwise see if this is the closest to a real version info bit string
// we have seen so far
int bitsDifference = FormatInformation.NumBitsDiffering(versionBits, targetVersion);
if (bitsDifference < bestDifference)
{
bestVersion = i + 7;
bestDifference = bitsDifference;
}
}
// We can tolerate up to 3 bits of error since no two version info codewords will
// differ in less than 8 bits.
if (bestDifference <= 3)
{
return(GetVersionForNumber(bestVersion));
}
// If we didn't find a close enough match, fail
return(null);
}
/// <summary>
/// Decodes the format information.
/// </summary>
/// <param name="maskedFormatInfo1">format info indicator, with mask still applied</param>
/// <param name="maskedFormatInfo2">The masked format info2.</param>
/// <returns>
/// information about the format it specifies, or <code>null</code>
/// if doesn't seem to match any known pattern
/// </returns>
internal static FormatInformation DecodeFormatInformation(int maskedFormatInfo1, int maskedFormatInfo2)
{
FormatInformation formatInfo = DoDecodeFormatInformation(maskedFormatInfo1, maskedFormatInfo2);
if (formatInfo != null)
{
return(formatInfo);
}
// Should return null, but, some QR codes apparently
// do not mask this info. Try again by actually masking the pattern
// first
return(DoDecodeFormatInformation(maskedFormatInfo1 ^ FORMAT_INFO_MASK_QR,
maskedFormatInfo2 ^ FORMAT_INFO_MASK_QR));
}
