source: trunk/libs/newlib/src/newlib/libc/string/swab.c @ 577

/*
FUNCTION
        <<swab>>---swap adjacent bytes

SYNOPSIS
        #include <unistd.h>
        void swab(const void *<[in]>, void *<[out]>, ssize_t <[n]>);

DESCRIPTION
        This function copies <[n]> bytes from the memory region
        pointed to by <[in]> to the memory region pointed to by
        <[out]>, exchanging adjacent even and odd bytes.

PORTABILITY
<<swab>> requires no supporting OS subroutines.
*/

#include <unistd.h>

void
swab (const void *b1,
        void *b2,
        ssize_t length)
{
  const char *from = b1;
  char *to = b2;
  ssize_t ptr;
  for (ptr = 1; ptr < length; ptr += 2)
    {
      char p = from[ptr];
      char q = from[ptr-1];
      to[ptr-1] = p;
      to[ptr  ] = q;
    }
  if (ptr == length) /* I.e., if length is odd, */
    to[ptr-1] = 0;   /* then pad with a NUL. */
}