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Diffstat (limited to 'lib/stat-size.h')
| -rw-r--r-- | lib/stat-size.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/lib/stat-size.h b/lib/stat-size.h new file mode 100644 index 0000000..bda00b7 --- /dev/null +++ b/lib/stat-size.h @@ -0,0 +1,100 @@ +/* macros useful in interpreting size-related values in struct stat. + Copyright (C) 1989, 1991-2023 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ +/* + Macros defined by this file (s is an rvalue of type struct stat): + + DEV_BSIZE: The device blocksize. But use ST_NBLOCKSIZE instead. + ST_BLKSIZE(s): Preferred (in the sense of best performance) I/O blocksize + for the file, in bytes. + ST_NBLOCKS(s): Number of blocks in the file, including indirect blocks. + ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS. + */ +#ifndef STAT_SIZE_H +#define STAT_SIZE_H + +/* This file uses HAVE_SYS_PARAM_H, HAVE_STRUCT_STAT_ST_BLOCKS. */ +#if !_GL_CONFIG_H_INCLUDED + #error "Please include config.h first." +#endif + +/* sys/param.h may define DEV_BSIZE */ +#if HAVE_SYS_PARAM_H +# include <sys/param.h> +#endif + + +/* Get or fake the disk device blocksize. + Usually defined by sys/param.h (if at all). */ +#if !defined DEV_BSIZE && defined BSIZE +# define DEV_BSIZE BSIZE +#endif +#if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */ +# define DEV_BSIZE BBSIZE +#endif +#ifndef DEV_BSIZE +# define DEV_BSIZE 4096 +#endif + + + +/* Extract or fake data from a 'struct stat'. + ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes. + ST_NBLOCKS: Number of blocks in the file, including indirect blocks. + ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS. */ +#ifndef HAVE_STRUCT_STAT_ST_BLOCKS +# define ST_BLKSIZE(statbuf) DEV_BSIZE + /* coreutils' fileblocks.c also uses BSIZE. */ +# if defined _POSIX_SOURCE || !defined BSIZE +# define ST_NBLOCKS(statbuf) \ + ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0)) +# else + /* This definition calls st_blocks, which is in the fileblocks module. */ +# define ST_NBLOCKS(statbuf) \ + (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) ? \ + st_blocks ((statbuf).st_size) : 0) +# endif +#else +/* When running 'rsh hpux11-system cat any-file', cat would + determine that the output stream had an st_blksize of 2147421096. + Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS + on 64-bit hosts. Somewhat arbitrarily, limit the "optimal" block + size to SIZE_MAX / 8 + 1. (Dividing SIZE_MAX by only 4 wouldn't + suffice, since "cat" sometimes multiplies the result by 4.) If + anyone knows of a system for which this limit is too small, please + report it as a bug in this code. */ +# define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \ + && (statbuf).st_blksize <= ((size_t)-1) / 8 + 1) \ + ? (statbuf).st_blksize : DEV_BSIZE) +# if defined hpux || defined __hpux__ || defined __hpux + /* HP-UX counts st_blocks in 1024-byte units. + This loses when mixing HP-UX and BSD file systems with NFS. */ +# define ST_NBLOCKSIZE 1024 +# endif +#endif + +#ifndef ST_NBLOCKS +# define ST_NBLOCKS(statbuf) ((statbuf).st_blocks) +#endif + +#ifndef ST_NBLOCKSIZE +# ifdef S_BLKSIZE +# define ST_NBLOCKSIZE S_BLKSIZE +# else +# define ST_NBLOCKSIZE 512 +# endif +#endif + +#endif /* STAT_SIZE_H */ |