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Diffstat (limited to 'src/H5Fsec2.c')
| -rw-r--r-- | src/H5Fsec2.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/src/H5Fsec2.c b/src/H5Fsec2.c new file mode 100644 index 0000000..f58725a --- /dev/null +++ b/src/H5Fsec2.c @@ -0,0 +1,314 @@ +/* + * Copyright (C) 1997 NCSA + * All rights reserved. + * + * Programmer: Robb Matzke <matzke@llnl.gov> + * Wednesday, October 22, 1997 + * + * Purpose: This is the Posix section-2 I/O subclass of H5Flow. + * + * Notes: This driver keeps track of its own file position in order to + * minimize the number of calls to lseek(). We assume that + * opening a file sets the current file position to the beginning + * and that read() and write() modify the file position as + * expected when they return successfully (unsuccessful return + * leaves the file position undefined). + */ +#include <H5private.h> +#include <H5Eprivate.h> +#include <H5Fprivate.h> +#include <H5MMprivate.h> + +#define PABLO_MASK H5F_sec2 +static hbool_t interface_initialize_g = FALSE; + +static H5F_low_t *H5F_sec2_open (const char *name, uintn flags); +static herr_t H5F_sec2_close (H5F_low_t *lf); +static herr_t H5F_sec2_read (H5F_low_t *lf, haddr_t addr, size_t size, + uint8 *buf); +static herr_t H5F_sec2_write (H5F_low_t *lf, haddr_t addr, size_t size, + const uint8 *buf); +static herr_t H5F_sec2_flush (H5F_low_t *lf); +static size_t H5F_sec2_size (H5F_low_t *lf); + + +const H5F_low_class_t H5F_LOW_SEC2[1] = {{ + H5F_sec2_open, /* open method */ + H5F_sec2_close, /* close method */ + H5F_sec2_read, /* read method */ + H5F_sec2_write, /* write method */ + H5F_sec2_flush, /* flush method */ + H5F_sec2_size, /* file size method */ +}}; + + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_open + * + * Purpose: Opens a file with name NAME. The FLAGS are a bit field with + * the possible values defined in H5F_low_open(). + * + * Errors: + * IO CANTOPENFILE Open failed. + * + * Return: Success: Low-level file pointer + * + * Failure: NULL + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static H5F_low_t * +H5F_sec2_open (const char *name, uintn flags) +{ + uintn oflags; + H5F_low_t *lf = NULL; + int fd; + + FUNC_ENTER (H5F_sec2_open, NULL, NULL); + + oflags = (flags & H5F_ACC_WRITE) ? O_RDWR : O_RDONLY; + oflags |= (flags & H5F_ACC_CREAT) ? O_CREAT : 0; + oflags |= (flags & H5F_ACC_EXCL) ? O_EXCL : 0; + oflags |= (flags & H5F_ACC_TRUNC) ? O_TRUNC : 0; + + if ((fd=open (name, oflags, 0666))<0) { + HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL);/*open failed*/ + } + + lf = H5MM_xcalloc (1, sizeof(H5F_low_t)); + lf->u.sec2.fd = fd; + lf->u.sec2.op = H5F_OP_SEEK; + lf->u.sec2.cur = 0; + + FUNC_LEAVE (lf); +} + + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_close + * + * Purpose: Closes a file. + * + * Errors: + * IO CLOSEERROR Close failed. + * + * Return: Success: SUCCEED + * + * Failure: FAIL + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static herr_t +H5F_sec2_close (H5F_low_t *lf) +{ + FUNC_ENTER (H5F_sec2_close, NULL, FAIL); + + if (close (lf->u.sec2.fd)<0) { + HRETURN_ERROR (H5E_IO, H5E_CLOSEERROR, FAIL); /*close failed*/ + } + lf->u.sec2.fd = -1; + + FUNC_LEAVE (SUCCEED); +} + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_read + * + * Purpose: Reads SIZE bytes beginning at address ADDR in file LF and + * places them in buffer BUF. Reading past the end of the + * file returns zeros instead of failing. + * + * Errors: + * IO READERROR Read failed. + * IO SEEKERROR Lseek failed. + * + * Return: Success: SUCCEED + * + * Failure: FAIL + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static herr_t +H5F_sec2_read (H5F_low_t *lf, haddr_t addr, size_t size, uint8 *buf) +{ + ssize_t n; + + FUNC_ENTER (H5F_sec2_read, NULL, FAIL); + + /* + * Optimize seeking. If that optimization is disabled then alwasy call + * lseek(). + */ + if (!H5F_OPT_SEEK || + lf->u.sec2.op==H5F_OP_UNKNOWN || lf->u.sec2.cur!=addr) { + if (lseek (lf->u.sec2.fd, addr, SEEK_SET)<0) { + HRETURN_ERROR (H5E_IO, H5E_SEEKERROR, FAIL); /*lseek failed*/ + } + lf->u.sec2.cur = addr; + } + + /* + * Read the data. If a read error occurs then set the last file operation + * to UNKNOWN because the file position isn't guaranteed by Posix. + */ + if ((n=read (lf->u.sec2.fd, buf, size))<0) { + lf->u.sec2.op = H5F_OP_UNKNOWN; + HRETURN_ERROR (H5E_IO, H5E_READERROR, FAIL); /*read failed*/ + } else if (n<size) { + HDmemset (buf+n, 0, size-n); + } + + /* + * Update the file position with the number of bytes actually read. This + * might be different than the number requested. + */ + lf->u.sec2.op = H5F_OP_READ; + lf->u.sec2.cur = addr + n; + + FUNC_LEAVE (SUCCEED); +} + + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_write + * + * Purpose: Writes SIZE bytes from the beginning of BUF into file LF at + * file address ADDR. + * + * Errors: + * IO SEEKERROR Lseek failed. + * IO WRITEERROR Write failed. + * + * Return: Success: SUCCEED + * + * Failure: FAIL + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static herr_t +H5F_sec2_write (H5F_low_t *lf, haddr_t addr, size_t size, const uint8 *buf) +{ + FUNC_ENTER (H5F_sec2_write, NULL, FAIL); + + /* + * Optimize seeking. If that optimization is disabled then always call + * lseek(). + */ + if (!H5F_OPT_SEEK || + lf->u.sec2.op==H5F_OP_UNKNOWN || lf->u.sec2.cur!=addr) { + if (lseek (lf->u.sec2.fd, addr, SEEK_SET)<0) { + HRETURN_ERROR (H5E_IO, H5E_SEEKERROR, FAIL); /*lseek failed*/ + } + lf->u.sec2.cur = addr; + } + + /* + * Read the data from the file. If the write failed then set the + * operation back to UNKNOWN since Posix doesn't gurantee its value. + */ + if (size != write (lf->u.sec2.fd, buf, size)) { + lf->u.sec2.op = H5F_OP_UNKNOWN; + HRETURN_ERROR (H5E_IO, H5E_WRITEERROR, FAIL); /*write failed*/ + } + + /* + * Update the file position. + */ + lf->u.sec2.op = H5F_OP_WRITE; + lf->u.sec2.cur = addr + size; + FUNC_LEAVE (SUCCEED); +} + + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_flush + * + * Purpose: Makes sure that all data is on disk. + * + * Errors: + * + * Return: Success: SUCCEED + * + * Failure: FAIL + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static herr_t +H5F_sec2_flush (H5F_low_t *lf) +{ + FUNC_ENTER (H5F_sec2_flush, NULL, FAIL); + + /* Not necessary with this driver */ + + FUNC_LEAVE (SUCCEED); +} + + +/*------------------------------------------------------------------------- + * Function: H5F_sec2_size + * + * Purpose: Returns the current size of the file in bytes. + * + * Bugs: There is no way to determine if this function failed. + * + * Errors: + * IO SEEKERROR Lseek failed. + * + * Return: Success: Size of file in bytes + * + * Failure: 0 + * + * Programmer: Robb Matzke + * Wednesday, October 22, 1997 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +static size_t +H5F_sec2_size (H5F_low_t *lf) +{ + off_t size; + + FUNC_ENTER (H5F_sec2_size, NULL, 0); + + if ((size=lseek (lf->u.sec2.fd, 0, SEEK_END))<0) { + lf->u.sec2.op = H5F_OP_UNKNOWN; + HRETURN_ERROR (H5E_IO, H5E_SEEKERROR, 0); /*lseek failed*/ + } + + lf->u.sec2.op = H5F_OP_SEEK; + lf->u.sec2.cur = size; + + FUNC_LEAVE (size); +} |