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/*=========================================================================
Program: GDCM (Grassroots DICOM). A DICOM library
Copyright (c) 2006-2011 Mathieu Malaterre
All rights reserved.
See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
#include "gdcmUnpacker12Bits.h"
namespace gdcm
{
bool Unpacker12Bits::Unpack(char *out, const char *in, size_t n)
{
if( n % 3 ) return false; // 3bytes are actually 2 words
// http://groups.google.com/group/comp.lang.c/msg/572bc9b085c717f3
short *q = (short*)out;
const unsigned char *p = (unsigned char*)in;
const unsigned char *end = p+n;
unsigned char b0,b1,b2;
while (p!=end)
{
b0 = *p++;
b1 = *p++;
b2 = *p++;
*q++ = (short)(((b1 & 0xf) << 8) + b0);
*q++ = (short)((b1>>4) + (b2<<4));
}
return true;
}
bool Unpacker12Bits::Pack(char *out, const char *in, size_t n)
{
if( n % 4 ) return false; // we need an even number of 'words' so that 2 words are split in 3 bytes
unsigned char *q = (unsigned char*)out;
const unsigned short *p = (unsigned short*)in;
const unsigned short *end = (unsigned short*)(in+n);
unsigned short b0,b1;
while(p!=end)
{
b0 = *p++;
b1 = *p++;
*q++ = (unsigned char)(b0 & 0xff);
*q++ = (unsigned char)((b0 >> 8) + ((b1 & 0xf) << 4));
*q++ = (unsigned char)(b1 >> 4);
}
return true;
}
} // end namespace gdcm
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