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/* $Id$ */
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include "cmsys.h"
#define BUFSIZE 512
/* Functions for fixed size record operations */
int
get_num_records(const char *fpath, size_t size)
{
struct stat st;
if (stat(fpath, &st) == -1)
return 0;
return st.st_size / size;
}
int
get_records_keep(const char *fpath, void *rptr, size_t size, int id, size_t number, int *fd)
{
assert(fpath);
assert(fd);
if (id < 1)
return -1;
if (*fd < 0 && (*fd = open(fpath, O_RDONLY, 0)) == -1)
return -1;
if (lseek(*fd, (off_t) (size * (id - 1)), SEEK_SET) == -1)
return 0;
if ((id = read(*fd, rptr, size * number)) == -1)
return -1;
return id / size;
}
int
get_records(const char *fpath, void *rptr, size_t size, int id, size_t number)
{
int res, fd = -1;
res = get_records_keep(fpath, rptr, size, id, number, &fd);
close(fd);
return res;
}
#ifndef get_record
int
get_record(const char *fpath, void *rptr, size_t size, int id)
{
return get_records(fpath, rptr, size, id, 1);
}
#endif
#ifndef get_record_keep
int
get_record_keep(const char *fpath, void *rptr, size_t size, int id, int *fd)
{
return get_records_keep(fpath, rptr, size, id, 1, fd);
}
#endif
int
substitute_record(const char *fpath, const void *rptr, size_t size, int id)
{
int fd;
off_t offset = size * (id - 1);
if (id < 1 || (fd = open(fpath, O_WRONLY | O_CREAT, 0644)) == -1)
return -1;
lseek(fd, offset, SEEK_SET);
PttLock(fd, offset, size, F_WRLCK);
write(fd, rptr, size);
PttLock(fd, offset, size, F_UNLCK);
close(fd);
return 0;
}
int
append_record(const char *fpath, const void *record, size_t size)
{
int fd, index = -2, fsize = 0;
if ((fd = open(fpath, O_WRONLY | O_CREAT, 0644)) == -1)
return -1;
flock(fd, LOCK_EX);
if ((fsize = lseek(fd, 0, SEEK_END)) < 0)
goto out;
index = fsize / size;
lseek(fd, index * size, SEEK_SET); // avoid offset
write(fd, record, size);
out:
flock(fd, LOCK_UN);
close(fd);
return index + 1;
}
int
delete_records(const char *fpath, size_t size, int id, size_t num)
{
char buf[BUFSIZE];
int fi, fo, locksize, readsize, c, d=0;
struct stat st;
off_t offset = size * (id - 1);
if ((fi=open(fpath, O_RDONLY, 0)) == -1)
return -1;
if ((fo=open(fpath, O_WRONLY, 0)) == -1) {
close(fi);
return -1;
}
if (fstat(fi, &st)==-1) {
close(fo);
close(fi);
return -1;
}
locksize = st.st_size - offset;
readsize = locksize - size*num;
if (locksize < 0 ) {
close(fo);
close(fi);
return -1;
}
PttLock(fo, offset, locksize, F_WRLCK);
if (readsize > 0) {
lseek(fi, offset+size, SEEK_SET);
lseek(fo, offset, SEEK_SET);
while (d < readsize && (c = read(fi, buf, BUFSIZE)) > 0) {
write(fo, buf, c);
d += c;
}
}
close(fi);
ftruncate(fo, st.st_size - size*num);
PttLock(fo, offset, locksize, F_UNLCK);
close(fo);
return 0;
}
#ifndef delete_record
int delete_record(const char *fpath, size_t size, int id)
{
return delete_records(fpath, size, id, 1);
}
#endif
int
apply_record(const char *fpath, int (*fptr) (void *item, void *optarg), size_t size, void *arg)
{
char buf[BUFSIZE];
int fd;
assert(size <= sizeof(buf));
if ((fd = open(fpath, O_RDONLY, 0)) == -1)
return -1;
while (read(fd, buf, size) == size)
if ((*fptr) (buf, arg) == 1) {
close(fd);
return 1;
}
close(fd);
return 0;
}
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