diff options
Diffstat (limited to 'src/H5Ffamily.c')
| -rw-r--r-- | src/H5Ffamily.c | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/src/H5Ffamily.c b/src/H5Ffamily.c index 402a96c..a138fea 100644 --- a/src/H5Ffamily.c +++ b/src/H5Ffamily.c @@ -30,16 +30,6 @@ static hbool_t interface_initialize_g = FALSE; #define INTERFACE_INIT NULL -/* - * Number of bits in the member address. This can be up to (but not - * including) the number of bits in the `off_t' type, but be warned that some - * operating systems are not able to write to the last possible address of a - * file, so a safe maximum is two less than the number of bits in an `off_t'. - * Smaller values result in files of a more manageable size (from a human - * perspective) but also limit the total logical size of the hdf5 file. - */ -#define H5F_FAM_DFLT_NBITS 26u /*64MB */ - #define H5F_FAM_MASK(N) (((uint64)1<<(N))-1) #define H5F_FAM_OFFSET(ADDR,N) ((off_t)((ADDR)->offset & H5F_FAM_MASK(N))) #define H5F_FAM_MEMBNO(ADDR,N) ((intn)((ADDR)->offset >> (N))) @@ -102,7 +92,7 @@ H5F_fam_open(const char *name, const H5F_access_t *access_parms, H5F_low_t *member = NULL; /*a family member */ char member_name[4096]; /*name of family member */ intn membno; /*member number (zero-origin) */ - size_t nbits = H5F_FAM_DFLT_NBITS; /*num bits in an offset */ + size_t nbits; /*num bits in an offset */ haddr_t tmp_addr; /*temporary address */ const H5F_low_class_t *memb_type; /*type of family member */ @@ -123,10 +113,10 @@ H5F_fam_open(const char *name, const H5F_access_t *access_parms, /* * If we're truncating the file then delete all but the first family - * member. Use the default number of bits for the offset. + * member. */ if ((flags & H5F_ACC_RDWR) && (flags & H5F_ACC_TRUNC)) { - for (membno = 1; /*void*/; membno++) { + for (membno=1; /*void*/; membno++) { sprintf(member_name, name, membno); if (!H5F_low_access(memb_type, member_name, access_parms->u.fam.memb_access, @@ -174,12 +164,13 @@ H5F_fam_open(const char *name, const H5F_access_t *access_parms, member = NULL; } - /* - * If the first and second files exists then round the first file size up - * to the next power of two and use that as the number of bits per family - * member. - */ + /* Calculate member size */ if (lf->u.fam.nmemb >= 2) { + /* + * If the first and second files exists then round the first file size + * up to the next power of two and use that as the number of bits per + * family member. + */ size_t size = H5F_low_size(lf->u.fam.memb[0], &tmp_addr); for (nbits=8*sizeof(size_t)-1; nbits>0; --nbits) { size_t mask = (size_t)1 << nbits; @@ -194,6 +185,23 @@ H5F_fam_open(const char *name, const H5F_access_t *access_parms, break; } } + } else { + /* + * Typically, the number of bits in the member offset can be up to two + * less than the number of bits in an `off_t'. On a 32-bit machine, + * for instance, files can be up to 2GB-1byte in size, but since HDF5 + * must have a power of two we're restricted to just 1GB. Smaller + * values result in files of a more manageable size (from a human + * perspective) but also limit the total logical size of the hdf5 file + * since most OS's only allow a certain number of open file + * descriptors (all family members are open at once). + */ +#ifdef H5F_DEBUG + if (access_parms->u.fam.offset_bits+2>=8*sizeof(off_t)) { + fprintf (stderr, "H5F: family member size may be too large.\n"); + } +#endif + nbits = MAX (access_parms->u.fam.offset_bits, 10); /*1K min*/ } lf->u.fam.offset_bits = nbits; |