Subversion Repositories HelenOS

Rev

Rev 4075 | Go to most recent revision | Show entire file | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed

Rev 4075 Rev 4505
Line 29... Line 29...
29 
/** @addtogroup net
 29 
/** @addtogroup net
30 
 *  @{
 30 
 *  @{
31 
 */
 31 
 */
32 
 
 32 
 
33 
/** @file
 33 
/** @file
34 
 *  General CRC computation implementation.
 34 
 *  General CRC and checksum computation implementation.
35 
 */
 35 
 */
36 
 
 36 
 
37 
#include <sys/types.h>
 37 
#include <sys/types.h>
38 
 
 38 
 
39 
#include "include/crc.h"
 39 
#include "include/crc.h"
Line 98... Line 98...
98 
        length -= 8;
 98 
        length -= 8;
99 
    }
 99 
    }
100 
    return seed;
 100 
    return seed;
101 
}
 101 
}
102 
 
 102 
 
- 
 
 103 
uint32_t compute_checksum( uint32_t seed, uint8_t * data, int length ){
- 
 
 104 
    int index;
- 
 
 105 
 
- 
 
 106 
    // sum all the 16 bit fields
- 
 
 107 
    for( index = 0; index < length - 1; index += 2 ){
- 
 
 108 
        seed += ( data[ index ] << 8 ) + data[ index + 1 ];
- 
 
 109 
    }
- 
 
 110 
 
- 
 
 111 
    // last odd byte with zero padding
- 
 
 112 
    if( index == length - 1 ){
- 
 
 113 
        seed += data[ index ] << 8;
- 
 
 114 
    }
- 
 
 115 
 
- 
 
 116 
    return seed;
- 
 
 117 
}
- 
 
 118 
 
- 
 
 119 
uint16_t compact_checksum( uint32_t sum ){
- 
 
 120 
    // shorten to the 16 bits
- 
 
 121 
    while( sum >> 16 ) sum = ( sum & 0xFFFF ) + ( sum >> 16 );
- 
 
 122 
 
- 
 
 123 
    return ( uint16_t ) sum;
- 
 
 124 
}
- 
 
 125 
 
103 
/** @}
 126 
/** @}
104 
 */
 127 
 */