swap.c File Reference

Byte swapping for little to big endian (and vice versa) conversion. More...

#include "libtpcmisc.h"

Go to the source code of this file.

Functions
int	little_endian ()
void	swap (void *from, void *to, int size)
void	swabip (void *buf, long long int size)
void	swawbip (void *buf, long long int size)
void	swawip (void *buf, long long int size)
void	printf32bits (void *buf)

Detailed Description

Byte swapping for little to big endian (and vice versa) conversion.

Author

Vesa Oikonen

Definition in file swap.c.

Function Documentation

little_endian()

int little_endian

(

)

Check whether current platform uses little endian byte order. See H&S Sec. 6.1.2 pp. 163-4.

Returns

Returns 1, if current platform is little endian, and 0 if not.

Definition at line 14 of file swap.c.

{
  int x=1;
  if(*(char *)&x==1) return(1); else return(0);
}

Referenced by anaReadHeader(), anaReadImagedata(), anaWriteHeader(), dcmFileWrite(), dcmitemGetInt(), dcmitemGetReal(), dcmReadFileTag(), dcmReadFileVL(), dcmReadFileVRVL(), dcmValueString(), dcmWriteFileTag(), dcmWriteFileVRVL(), ecat63Create(), ecat63Matenter(), ecat63ReadAttnheader(), ecat63ReadImageheader(), ecat63ReadMainheader(), ecat63ReadMatdata(), ecat63ReadMatlist(), ecat63ReadNormheader(), ecat63ReadScanheader(), ecat63WriteAttnheader(), ecat63WriteImageheader(), ecat63WriteMainheader(), ecat63WriteMatdata(), ecat63WriteNormheader(), ecat63WriteScanheader(), ecat7Create(), ecat7EnterMatrix(), ecat7Read2DNormheader(), ecat7Read2DScanheader(), ecat7ReadAttenheader(), ecat7ReadImageheader(), ecat7ReadMainheader(), ecat7ReadMatlist(), ecat7ReadMatrixdata(), ecat7ReadNormheader(), ecat7ReadPolmapheader(), ecat7ReadScanheader(), ecat7Write2DNormheader(), ecat7Write2DScanheader(), ecat7WriteAttenheader(), ecat7WriteImageheader(), ecat7WriteMainheader(), ecat7WriteMatrixdata(), ecat7WriteNormheader(), ecat7WritePolmapheader(), ecat7WriteScanheader(), hrrtMakeCalHdr(), imgSetNiftiHeader(), imgWriteAnalyze(), imgWriteAnalyzeFrame(), niftiReadHeader(), niftiReadImagedata(), niftiWriteHeader(), tiffWriteImg(), and upetReadImagedata().

printf32bits()

void printf32bits

(

void *

buf

)

Printfs as bit string the 32-bit variable pointed to by buf. Far from being optimized, thus only for testing and development purposes.

Parameters

buf	Pointer to memory

Definition at line 133 of file swap.c.

                             {
  unsigned int u, i;
  int j;
 
  memcpy(&u, buf, 4);
  for(i=32; i>0; i--) {
    j=i-1;if(i<32 && (i%8)==0) printf(" ");
    if(u & (1L<<j)) printf("1"); else printf("0");
  }
  printf("\n");
}

swabip()

void swabip	(	void *	buf,
		long long int	size )

In-place swab, replaces the non-ANSI function swab(), which may not work if data is overlapping.

Parameters

buf	Pointer to memory
size	Size of buf in bytes

Definition at line 72 of file swap.c.

  {
  unsigned char c;
 
  for(long long i=1; i<size; i+=2) {
    c=*((unsigned char *)buf+i);
    *((unsigned char *)buf+i)=*((unsigned char *)buf+(i-1));
    *((unsigned char *)buf+(i-1))=c;
  }
}

Referenced by anaReadHeader(), anaReadImagedata(), anaWriteHeader(), dcmFileWrite(), dcmWriteFileTag(), ecat63ReadAttnheader(), ecat63ReadImageheader(), ecat63ReadMainheader(), ecat63ReadMatdata(), ecat63ReadNormheader(), ecat63ReadScanheader(), ecat63rFloat(), ecat63wFloat(), ecat63WriteAttnheader(), ecat63WriteImageheader(), ecat63WriteMainheader(), ecat63WriteMatdata(), ecat63WriteNormheader(), ecat63WriteScanheader(), ecat7Read2DNormheader(), ecat7Read2DScanheader(), ecat7ReadAttenheader(), ecat7ReadImageheader(), ecat7ReadMainheader(), ecat7ReadMatrixdata(), ecat7ReadNormheader(), ecat7ReadPolmapheader(), ecat7ReadScanheader(), ecat7rFloat(), ecat7Write2DNormheader(), ecat7Write2DScanheader(), ecat7WriteAttenheader(), ecat7WriteImageheader(), ecat7WriteMainheader(), ecat7WriteMatrixdata(), ecat7WriteNormheader(), ecat7WritePolmapheader(), ecat7WriteScanheader(), imgWriteAnalyze(), imgWriteAnalyzeFrame(), niftiReadHeader(), niftiReadImagedata(), niftiWriteHeader(), and upetReadImagedata().

swap()

void swap	(	void *	from,
		void *	to,
		int	size )

Swaps the specified short int, int, long int, float, or double from little endian to big endian or vice versa. Arguments are allowed to overlap.

Parameters

from	Pointer to a short int, int, long int, float, or double variable
to	Pointer to a short int, int, long int, float, or double variable
size	Size of from and to (byte nr) must be 1, 2, 4 or 8.

Definition at line 31 of file swap.c.

                                          {
  unsigned char c;
  unsigned short int s;
  unsigned long l;
  
  switch(size) {
    case 1:
      *(char *)to=*(char *)from;
      break;
    case 2:
      c=*(unsigned char *)from;
      *(unsigned char *)to = *((unsigned char *)from+1);
      *((unsigned char *)to+1) = c; 
      /*swab(from, to, size); // NOT ANSI */
      break;
    case 4:
      s=*(unsigned short *)from;
      *(unsigned short *)to = *((unsigned short *)from+1);
      *((unsigned short *)to+1) = s;
      swap((char*)to, (char*)to, 2);
      swap((char*)((unsigned short *)to+1), (char*)((unsigned short *)to+1), 2);
      break;
    case 8:
      l=*(unsigned long *)from;
      *(unsigned long *)to = *((unsigned long *)from+1);
      *((unsigned long *)to+1) = l;
      swap((char *)to, (char *)to, 4);
      swap((char*)((unsigned long *)to+1), (char*)((unsigned long *)to+1), 4);
      break;
  }
}

Referenced by dcmitemGetInt(), dcmitemGetReal(), dcmReadFileTag(), dcmReadFileVL(), dcmReadFileVRVL(), dcmValueString(), dcmWriteFileVRVL(), intExpand(), and swap().

swawbip()

void swawbip	(	void *	buf,
		long long int	size )

In-place swab and swaw, switches words and bytes from an array of 4-byte ints or floats.

Parameters

buf	Pointer to memory
size	Size of buf in bytes

Definition at line 93 of file swap.c.

  {
  unsigned char c, *cptr;
 
  cptr=(unsigned char*)buf;
  for(long long i=0; i<size; i+=4, cptr+=4) {
    c=cptr[0]; cptr[0]=cptr[3]; cptr[3]=c;
    c=cptr[1]; cptr[1]=cptr[2]; cptr[2]=c;
  }
}

Referenced by anaReadHeader(), anaReadImagedata(), anaWriteHeader(), ecat63Create(), ecat63Matenter(), ecat63ReadMatdata(), ecat63ReadMatlist(), ecat63rFloat(), ecat63rInt(), ecat63wFloat(), ecat63wInt(), ecat63WriteMatdata(), ecat7Create(), ecat7EnterMatrix(), ecat7Read2DNormheader(), ecat7Read2DScanheader(), ecat7ReadAttenheader(), ecat7ReadImageheader(), ecat7ReadMainheader(), ecat7ReadMatlist(), ecat7ReadMatrixdata(), ecat7ReadNormheader(), ecat7ReadPolmapheader(), ecat7ReadScanheader(), ecat7rFloat(), ecat7rInt(), ecat7Write2DNormheader(), ecat7Write2DScanheader(), ecat7WriteAttenheader(), ecat7WriteImageheader(), ecat7WriteMainheader(), ecat7WriteMatrixdata(), ecat7WriteNormheader(), ecat7WritePolmapheader(), ecat7WriteScanheader(), hrrtMakeCalHdr(), niftiReadHeader(), niftiReadImagedata(), niftiWriteHeader(), and upetReadImagedata().

swawip()

void swawip	(	void *	buf,
		long long int	size )

In-place swaw, switches words (but not bytes) from an array of 4-byte ints or floats.

Parameters

buf	Pointer to memory
size	Size of buf in bytes

Definition at line 114 of file swap.c.

  {
  unsigned short int s, *sptr;
 
  sptr=(unsigned short int*)buf;
  for(long long i=0; i<size; i+=4, sptr+=2) {
    s=sptr[0]; sptr[0]=sptr[1]; sptr[1]=s;
  }
}

Referenced by ecat63rFloat(), ecat63wFloat(), and ecat7rFloat().