diff options
| -rw-r--r-- | src/H5checksum.c | 26 |
1 files changed, 7 insertions, 19 deletions
diff --git a/src/H5checksum.c b/src/H5checksum.c index f4d702b..3aafd3d 100644 --- a/src/H5checksum.c +++ b/src/H5checksum.c @@ -90,10 +90,9 @@ uint32_t H5_fletcher32(const void *_data, size_t _len) { - const uint16_t *data = (const uint16_t *)_data; /* Pointer to the data to be summed */ + const uint8_t *data = (const uint8_t *)_data; /* Pointer to the data to be summed */ size_t len = _len / 2; /* Length in 16-bit words */ uint32_t sum1 = 0xffff, sum2 = 0xffff; - uint32_t ret_value; /* Return value */ FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5_fletcher32) @@ -102,16 +101,15 @@ H5_fletcher32(const void *_data, size_t _len) HDassert(_len > 0); /* Compute checksum for pairs of bytes */ - /* The magic "360" value is is the largest number of sums that can be - * performed without numeric overflow. See the Wikipedia page for - * Fletcher's checksum: http://en.wikipedia.org/wiki/Fletcher%27s_checksum - * for more details, etc. + /* (the magic "360" value is is the largest number of sums that can be + * performed without numeric overflow) */ while (len) { unsigned tlen = len > 360 ? 360 : len; len -= tlen; do { - sum1 += *data++; + sum1 += (((uint16_t)data[0]) << 8) | ((uint16_t)data[1]); + data += 2; sum2 += sum1; } while (--tlen); sum1 = (sum1 & 0xffff) + (sum1 >> 16); @@ -120,7 +118,7 @@ H5_fletcher32(const void *_data, size_t _len) /* Check for odd # of bytes */ if(_len % 2) { - sum1 += *(const uint8_t *)data; + sum1 += ((uint16_t)*data) << 8; sum2 += sum1; sum1 = (sum1 & 0xffff) + (sum1 >> 16); sum2 = (sum2 & 0xffff) + (sum2 >> 16); @@ -130,16 +128,6 @@ H5_fletcher32(const void *_data, size_t _len) sum1 = (sum1 & 0xffff) + (sum1 >> 16); sum2 = (sum2 & 0xffff) + (sum2 >> 16); -/* Byteswap result on little-endian platforms */ -#ifdef H5_WORDS_BIGENDIAN - ret_value = sum2 << 16 | sum1; -#else /* H5_WORDS_BIGENDIAN */ - ret_value = (sum2 << 8) & 0x00ff0000; - ret_value |= (sum2 << 24) & 0xff000000; - ret_value |= (sum1 << 8) & 0x0000ff00; - ret_value |= (sum1 >> 8) & 0x000000ff; -#endif /* H5_WORDS_BIGENDIAN */ - - FUNC_LEAVE_NOAPI(ret_value) + FUNC_LEAVE_NOAPI(sum2 << 16 | sum1) } /* end H5_fletcher32() */ |