Fix tail to work on files bigger than 2GB.
PR: 14786 Reviewed by: iedowse
This commit is contained in:
David Malone
parent
5c620e2dad
commit
726098d35e
@ -31,11 +31,24 @@
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* SUCH DAMAGE.
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*
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* @(#)extern.h 8.1 (Berkeley) 6/6/93
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*
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* $FreeBSD$
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*/
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#define WR(p, size) \
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#define WR(p, size) do { \
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if (write(STDOUT_FILENO, p, size) != size) \
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oerr();
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oerr(); \
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} while(0)
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#define TAILMAPLEN (4<<20)
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struct mapinfo {
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off_t mapoff;
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off_t maxoff;
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size_t maplen;
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char *start;
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int fd;
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};
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enum STYLE { NOTSET = 0, FBYTES, FLINES, RBYTES, RLINES, REVERSE };
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@ -47,6 +60,8 @@ int lines __P((FILE *, off_t));
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void ierr __P((void));
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void oerr __P((void));
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int mapprint __P((struct mapinfo *, off_t, off_t));
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int maparound __P((struct mapinfo *, off_t));
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extern int Fflag, fflag, rflag, rval;
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extern char *fname;
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@ -267,55 +267,46 @@ rlines(fp, off, sbp)
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long off;
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struct stat *sbp;
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{
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off_t size;
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char *p;
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char *start;
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struct mapinfo map;
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off_t curoff, size;
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int i;
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if (!(size = sbp->st_size))
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return;
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map.start = NULL;
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map.fd = fileno(fp);
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map.mapoff = map.maxoff = size;
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/*
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* size not passed directly to mmap() below because unclear error
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* diagnostic "Invalid argument".
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* Last char is special, ignore whether newline or not. Note that
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* size == 0 is dealt with above, and size == 1 sets curoff to -1.
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*/
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if (size > SIZE_T_MAX || size < 0) {
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errno = EFBIG;
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ierr();
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exit(1);
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}
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/*
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* XXX: FIXME - mmap() not support files over 2GB
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* Large file processing require alternative implementation,
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* for now print nice error diagnostic at least.
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*/
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if (size > SSIZE_MAX) {
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errno = EFBIG;
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ierr();
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exit(1);
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}
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if ((start = mmap(NULL, (size_t)size,
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PROT_READ, MAP_SHARED, fileno(fp), (off_t)0)) == MAP_FAILED) {
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ierr();
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exit(1);
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}
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/* Last char is special, ignore whether newline or not. */
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for (p = start + size - 1; --size;)
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if (*--p == '\n' && !--off) {
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++p;
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break;
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curoff = size - 2;
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while (curoff >= 0) {
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if (curoff < map.mapoff && maparound(&map, curoff) != 0) {
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ierr();
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return;
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}
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for (i = curoff - map.mapoff; i >= 0; i--)
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if (map.start[i] == '\n' && --off == 0)
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break;
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/* `i' is either the map offset of a '\n', or -1. */
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curoff = map.mapoff + i;
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if (i >= 0)
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break;
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}
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curoff++;
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if (mapprint(&map, curoff, size - curoff) != 0) {
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ierr();
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exit(1);
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}
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/* Set the file pointer to reflect the length displayed. */
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size = sbp->st_size - size;
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WR(p, size);
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if (fseek(fp, 0L, SEEK_END) == -1) {
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if (fseeko(fp, sbp->st_size, SEEK_SET) == -1) {
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ierr();
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return;
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}
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if (munmap(start, (size_t)sbp->st_size)) {
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if (map.start != NULL && munmap(map.start, map.maplen)) {
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ierr();
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return;
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}
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@ -44,6 +44,7 @@ static const char rcsid[] =
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdio.h>
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@ -64,3 +65,57 @@ oerr()
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{
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err(1, "stdout");
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}
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/*
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* Print `len' bytes from the file associated with `mip', starting at
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* absolute file offset `startoff'. May move map window.
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*/
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int
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mapprint(mip, startoff, len)
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struct mapinfo *mip;
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off_t startoff, len;
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{
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int n;
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while (len > 0) {
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if (startoff < mip->mapoff || startoff >= mip->mapoff +
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mip->maplen) {
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if (maparound(mip, startoff) != 0)
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return (1);
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}
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n = (mip->mapoff + mip->maplen) - startoff;
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if (n > len)
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n = len;
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WR(mip->start + (startoff - mip->mapoff), n);
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startoff += n;
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len -= n;
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}
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return (0);
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}
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/*
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* Move the map window so that it contains the byte at absolute file
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* offset `offset'. The start of the map window will be TAILMAPLEN
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* aligned.
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*/
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int
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maparound(mip, offset)
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struct mapinfo *mip;
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off_t offset;
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{
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if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0)
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return (1);
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mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1);
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mip->maplen = TAILMAPLEN;
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if (mip->maplen > mip->maxoff - mip->mapoff)
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mip->maplen = mip->maxoff - mip->mapoff;
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if (mip->maplen <= 0)
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abort();
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if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED,
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mip->fd, mip->mapoff)) == MAP_FAILED)
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return (1);
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return (0);
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}
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@ -114,43 +114,63 @@ r_reg(fp, style, off, sbp)
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long off;
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struct stat *sbp;
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{
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off_t size;
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int llen;
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char *p;
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char *start;
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struct mapinfo map;
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off_t curoff, size, lineend;
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int i;
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if (!(size = sbp->st_size))
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return;
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if (size > SIZE_T_MAX) {
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errno = EFBIG;
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ierr();
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return;
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}
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map.start = NULL;
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map.mapoff = map.maxoff = size;
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map.fd = fileno(fp);
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if ((start = mmap(NULL, (size_t)size,
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PROT_READ, MAP_SHARED, fileno(fp), (off_t)0)) == MAP_FAILED) {
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ierr();
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return;
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}
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p = start + size - 1;
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if (style == RBYTES && off < size)
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size = off;
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/* Last char is special, ignore whether newline or not. */
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for (llen = 1; --size; ++llen)
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if (*--p == '\n') {
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WR(p + 1, llen);
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llen = 0;
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if (style == RLINES && !--off) {
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++p;
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break;
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/*
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* Last char is special, ignore whether newline or not. Note that
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* size == 0 is dealt with above, and size == 1 sets curoff to -1.
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*/
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curoff = size - 2;
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lineend = size;
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while (curoff >= 0) {
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if (curoff < map.mapoff || curoff >= map.mapoff + map.maplen) {
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if (maparound(&map, curoff) != 0) {
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ierr();
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return;
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}
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}
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if (llen)
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WR(p, llen);
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if (munmap(start, (size_t)sbp->st_size))
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for (i = curoff - map.mapoff; i >= 0; i--) {
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if (style == RBYTES && --off == 0)
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break;
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if (map.start[i] == '\n')
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break;
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}
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/* `i' is either the map offset of a '\n', or -1. */
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curoff = map.mapoff + i;
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if (i < 0)
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continue;
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/* Print the line and update offsets. */
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if (mapprint(&map, curoff + 1, lineend - curoff - 1) != 0) {
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ierr();
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return;
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}
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lineend = curoff + 1;
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curoff--;
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if (style == RLINES)
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off--;
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if (off == 0 && style != REVERSE) {
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/* Avoid printing anything below. */
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curoff = 0;
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break;
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}
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}
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if (curoff < 0 && mapprint(&map, 0, lineend) != 0) {
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ierr();
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return;
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}
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if (map.start != NULL && munmap(map.start, map.maplen))
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ierr();
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}
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