/*
* rlines -- display the last offset lines of the file.
*/
static void
rlines(FILE *fp, const char *fn, off_t off, struct stat *sbp)
{
struct mapinfo map;
off_t curoff, size;
int i;
if (!(size = sbp->st_size))
return;
map.start = NULL;
map.fd = fileno(fp);
map.mapoff = map.maxoff = size;
/*
* Last char is special, ignore whether newline or not. Note that
* size == 0 is dealt with above, and size == 1 sets curoff to -1.
*/
curoff = size - 2;
while (curoff >= 0) {
if (curoff < map.mapoff && maparound(&map, curoff) != 0) {
ierr(fn);
return;
}
for (i = curoff - map.mapoff; i >= 0; i--)
if (map.start[i] == '\n' && --off == 0)
break;
/* `i' is either the map offset of a '\n', or -1. */
curoff = map.mapoff + i;
if (i >= 0)
break;
}
curoff++;
if (mapprint(&map, curoff, size - curoff) != 0) {
ierr(fn);
exit(1);
}
/* Set the file pointer to reflect the length displayed. */
if (fseeko(fp, sbp->st_size, SEEK_SET) == -1) {
ierr(fn);
return;
}
if (map.start != NULL && munmap(map.start, map.maplen)) {
ierr(fn);
return;
}
}
/*
* Print `len' bytes from the file associated with `mip', starting at
* absolute file offset `startoff'. May move map window.
*/
int
mapprint(struct mapinfo *mip, off_t startoff, off_t len)
{
int n;
while (len > 0) {
if (startoff < mip->mapoff || startoff >= mip->mapoff +
(off_t)mip->maplen) {
if (maparound(mip, startoff) != 0)
return (1);
}
n = (mip->mapoff + mip->maplen) - startoff;
if (n > len)
n = len;
WR(mip->start + (startoff - mip->mapoff), n);
startoff += n;
len -= n;
}
return (0);
}
/*
* r_reg -- display a regular file in reverse order by line.
*/
static void
r_reg(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
{
struct mapinfo map;
off_t curoff, size, lineend;
int i;
if (!(size = sbp->st_size))
return;
map.start = NULL;
map.mapoff = map.maxoff = size;
map.fd = fileno(fp);
/*
* Last char is special, ignore whether newline or not. Note that
* size == 0 is dealt with above, and size == 1 sets curoff to -1.
*/
curoff = size - 2;
lineend = size;
while (curoff >= 0) {
if (curoff < map.mapoff ||
curoff >= map.mapoff + (off_t)map.maplen) {
if (maparound(&map, curoff) != 0) {
ierr();
return;
}
}
for (i = curoff - map.mapoff; i >= 0; i--) {
if (style == RBYTES && --off == 0)
break;
if (map.start[i] == '\n')
break;
}
/* `i' is either the map offset of a '\n', or -1. */
curoff = map.mapoff + i;
if (i < 0)
continue;
/* Print the line and update offsets. */
if (mapprint(&map, curoff + 1, lineend - curoff - 1) != 0) {
ierr();
return;
}
lineend = curoff + 1;
curoff--;
if (style == RLINES)
off--;
if (off == 0 && style != REVERSE) {
/* Avoid printing anything below. */
curoff = 0;
break;
}
}
if (curoff < 0 && mapprint(&map, 0, lineend) != 0) {
ierr();
return;
}
if (map.start != NULL && munmap(map.start, map.maplen))
ierr();
}
