swap.c

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/*****************************************************************************/
#include "libtpcmisc.h"
/*****************************************************************************/
 
/*****************************************************************************/
int little_endian()
{
  int x=1;
  if(*(char *)&x==1) return(1); else return(0);
}
/*****************************************************************************/
 
/*****************************************************************************/
void swap(void *from, void *to, int size) {
  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;
  }
}
/*****************************************************************************/
 
/*****************************************************************************/
void swabip(
  void *buf, long long int size
) {
  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;
  }
}
/*****************************************************************************/
 
/*****************************************************************************/
void swawbip(
  void *buf, long long int size
) {
  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;
  }
}
/*****************************************************************************/
 
/*****************************************************************************/
void swawip(
  void *buf, long long int size
) {
  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;
  }
}
/*****************************************************************************/
 
/*****************************************************************************/
void printf32bits(void *buf) {
  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");
}
/*****************************************************************************/
 
/*****************************************************************************/