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Byte order utililities

Previous post little, big endianness explained deals with theoretical part of endianness, now let us write some utility functions for endainness.

Little Endian To Host: Data we are taking here is little endian data and this program converts little endian to host format. program takes a buffer of data and rearranges it to the native order of the machine. if the native order is little endian no conversion happens.

IsLittleEndian function is already listed in previous post, as it is used here, we?ve copied that function?

bool IsLittleEndian()
{
int x=1 ;
if(*(char *) &x == 1)
return true;
else
return false;
}

int LittleEndianToNative(char *data, unsigned int size)
{
char tmp;
char *sptr, *eptr;

if (!data || !size)
{
return -1;
}

if (IsLittleEndian())
{
return 0;
}

sptr = data;
eptr = data + size - 1;

while (sptr <= eptr-1)
  {
    tmp  = *sptr;
    *sptr++ = *eptr;
    *eptr– = tmp;
  }
  return 0;
}

Host to Little Endian:

Data we are taking here is host or native order data and this program converts host to little endian format. program takes a buffer of data and rearranges it to little endian. if the native order is little endian no conversion happens.

int NativeToLittleEndian(char *data, unsigned int size)
{
//conversion process is same
return LittleEndianToNative(data, size);
}

Big Endian To Host:

Data we are taking here is big endian data and this program converts big endian to native order format. program takes a buffer of data and rearranges it to the native order of the machine. if the native order is big endian no conversion happens.

int BigEndianToNative(char *data, unsigned int size)
{
char tmp;
char *sptr, *eptr;

if (!data || !size) { return -1; }

if (!IsLittleEndian())
{
//no conversion required
return 0;
}
sptr = data;
eptr = data + size - 1;

while (sptr <= eptr-1)
  {
    tmp  = *sptr;
    *sptr++ = *eptr;
    *eptr– = tmp;
  }
  return 0;
}

Host to Big Endian:

Data we are taking here is host or native order data and this program converts host to big endian format. program takes a buffer of data and rearranges it to big endian. if the native order is big endian no conversion happens.

int NativeToBigEndian(char *data, unsigned int size)
{
//conversion process is same
return BigEndianToNative(data, size);
}

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Related Blog Items

• Finding endianness
• Binary Streams Utility Classes
• Structure padding explained
• c/c++ blogging - January 10, 2007
• Buffer Overruns (on Mobile Applications) - Part2

This entry was written by ponnada and posted on December 27, 2006 at 1:05 pm and filed under C/C++ Programming Concepts, Embedded Systems Programming. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: Trackback URL.