diff options
Diffstat (limited to 'src/H5Zfletcher32.c')
| -rw-r--r-- | src/H5Zfletcher32.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/H5Zfletcher32.c b/src/H5Zfletcher32.c new file mode 100644 index 0000000..bd4c68f --- /dev/null +++ b/src/H5Zfletcher32.c @@ -0,0 +1,161 @@ +/* + * Copyright © 1999-2001 NCSA + * All rights reserved. + * + * Programmer: Raymond Lu<slu@ncsa.uiuc.edu> + * Jan 3, 2003 + */ +#include "H5private.h" +#include "H5Eprivate.h" +#include "H5MMprivate.h" +#include "H5Zprivate.h" + +#ifdef H5_HAVE_FILTER_FLETCHER32 + +#define FLETCHER_LEN 4 + +/* Interface initialization */ +#define PABLO_MASK H5Z_fletcher32_mask +#define INTERFACE_INIT NULL +static int interface_initialize_g = 0; + + +/*------------------------------------------------------------------------- + * Function: H5Z_filter_fletcher32_compute + * + * Purpose: Implement an Fletcher32 Checksum using 1's complement. + * + * Return: Success: Fletcher32 value + * + * Failure: Can't fail + * + * Programmer: Raymond Lu + * Jan 3, 2003 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static unsigned int H5Z_filter_fletcher32_compute(unsigned short *buf, size_t len) +{ + size_t count = len; + register unsigned int s1 = 0; + register unsigned int s2 = 0; + unsigned short *src = buf; + + FUNC_ENTER_NOINIT(H5Z_filter_fletcher32_compute); + + /* Compute checksum */ + while(count > 1) { + s1 += *src++; + if(s1 & 0xFFFF0000) { /*Wrap around carry if occurred*/ + s1 &= 0xFFFF; + s1++; + } + s2 += s1; + if(s2 & 0xFFFF0000) { /*Wrap around carry if occurred*/ + s2 &= 0xFFFF; + s2++; + } + count -= 2; + } + + if(count==1) { + s1 += *(unsigned char*)src; + if(s1 & 0xFFFF0000) { /*Wrap around carry if occurred*/ + s1 &= 0xFFFF; + s1++; + } + s2 += s1; + if(s2 & 0xFFFF0000) { /*Wrap around carry if occurred*/ + s2 &= 0xFFFF; + s2++; + } + } + + FUNC_LEAVE_NOAPI((s2 << 16) + s1); +} + + +/*------------------------------------------------------------------------- + * Function: H5Z_filter_fletcher32 + * + * Purpose: Implement an I/O filter of Fletcher32 Checksum + * + * Return: Success: size of data plus the size of Fletcher32 value + * + * Failure: 0 + * + * Programmer: Raymond Lu + * Jan 3, 2003 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +size_t +H5Z_filter_fletcher32 (unsigned flags, size_t cd_nelmts, const unsigned cd_values[], + size_t nbytes, size_t *buf_size, void **buf) +{ + size_t ret_value = 0; + void *outbuf = NULL; + + unsigned char *src = (unsigned char*)(*buf); + unsigned int fletcher = 0; + + FUNC_ENTER_NOAPI(H5Z_filter_fletcher32, 0); + + assert(sizeof(unsigned int)==4); + + if (flags & H5Z_FLAG_REVERSE) { /* Read */ + size_t src_nbytes = nbytes; + unsigned int origin_fletcher; + + /* Do checksum if it's enabled for read; otherwise skip it + * to save performance. */ + if (!(flags & H5Z_FLAG_SKIP_EDC)) { /* Read */ + unsigned char *tmp_src; + + src_nbytes -= FLETCHER_LEN; + tmp_src=src+src_nbytes; + UINT32DECODE(tmp_src, origin_fletcher); + + /* Compute checksum */ + fletcher = H5Z_filter_fletcher32_compute((unsigned short*)src,src_nbytes); + + if(origin_fletcher != fletcher) + HGOTO_ERROR(H5E_STORAGE, H5E_READERROR, 0, "data error detected by Fletcher32 checksum"); + } + + *buf_size = nbytes - FLETCHER_LEN; + ret_value = *buf_size; + } else { /* Write */ + unsigned char *dst; + + /* Compute checksum */ + fletcher = H5Z_filter_fletcher32_compute((unsigned short*)src,nbytes); + + if (NULL==(dst=outbuf=H5MM_malloc(nbytes+FLETCHER_LEN))) + HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0, "unable to allocate Fletcher32 checksum destination buffer"); + + /* Copy raw data */ + HDmemcpy((void*)dst, (void*)(*buf), nbytes); + + /* Append checksum to raw data */ + dst += nbytes; + UINT32ENCODE(dst, fletcher); + + *buf_size = nbytes + FLETCHER_LEN; + H5MM_xfree(*buf); + *buf = outbuf; + outbuf = NULL; + ret_value = *buf_size; + } + +done: + if(outbuf) + H5MM_xfree(outbuf); + FUNC_LEAVE_NOAPI(ret_value); +} + +#endif /* H5_HAVE_FILTER_FLETCHER32 */ |