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-rw-r--r--usr.bin/cmp/regular.c66
1 files changed, 52 insertions, 14 deletions
diff --git a/usr.bin/cmp/regular.c b/usr.bin/cmp/regular.c
index e2d0435..ec46827 100644
--- a/usr.bin/cmp/regular.c
+++ b/usr.bin/cmp/regular.c
@@ -51,6 +51,9 @@ static const char sccsid[] = "@(#)regular.c 8.3 (Berkeley) 4/2/94";
#include "extern.h"
+static u_char *remmap __P((u_char *, int, off_t));
+#define MMAP_CHUNK (8*1024*1024)
+
#define ROUNDPAGE(i) ((i) & ~pagemask)
void
@@ -59,7 +62,7 @@ c_regular(fd1, file1, skip1, len1, fd2, file2, skip2, len2)
char *file1, *file2;
off_t skip1, len1, skip2, len2;
{
- u_char ch, *p1, *p2;
+ u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
off_t byte, length, line;
int dfound;
off_t pagemask, off1, off2;
@@ -81,23 +84,25 @@ c_regular(fd1, file1, skip1, len1, fd2, file2, skip2, len2)
off2 = ROUNDPAGE(skip2);
length = MIN(len1, len2);
- if (length > SIZE_T_MAX)
- return (c_special(fd1, file1, skip1, fd2, file2, skip2));
- if ((p1 = (u_char *)mmap(NULL, (size_t)len1 + skip1 % pagesize,
- PROT_READ, MAP_SHARED, fd1, off1)) == (u_char *)MAP_FAILED)
- err(ERR_EXIT, "%s", file1);
+ if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
+ c_special(fd1, file1, skip1, fd2, file2, skip2);
+ return;
+ }
- madvise(p1, len1 + skip1 % pagesize, MADV_SEQUENTIAL);
- if ((p2 = (u_char *)mmap(NULL, (size_t)len2 + skip2 % pagesize,
- PROT_READ, MAP_SHARED, fd2, off2)) == (u_char *)MAP_FAILED)
- err(ERR_EXIT, "%s", file2);
- madvise(p2, len2 + skip2 % pagesize, MADV_SEQUENTIAL);
+ if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
+ munmap(m1, MMAP_CHUNK);
+ c_special(fd1, file1, skip1, fd2, file2, skip2);
+ return;
+ }
dfound = 0;
- p1 += skip1 - off1;
- p2 += skip2 - off2;
- for (byte = line = 1; length--; ++p1, ++p2, ++byte) {
+ e1 = m1 + MMAP_CHUNK;
+ e2 = m2 + MMAP_CHUNK;
+ p1 = m1 + (skip1 - off1);
+ p2 = m2 + (skip2 - off2);
+
+ for (byte = line = 1; length--; ++byte) {
if ((ch = *p1) != *p2) {
if (xflag) {
dfound = 1;
@@ -111,10 +116,43 @@ c_regular(fd1, file1, skip1, len1, fd2, file2, skip2, len2)
}
if (ch == '\n')
++line;
+ if (++p1 == e1) {
+ off1 += MMAP_CHUNK;
+ if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
+ munmap(m2, MMAP_CHUNK);
+ err(ERR_EXIT, "remmap %s", file1);
+ }
+ e1 = m1 + MMAP_CHUNK;
+ }
+ if (++p2 == e2) {
+ off2 += MMAP_CHUNK;
+ if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
+ munmap(m1, MMAP_CHUNK);
+ err(ERR_EXIT, "remmap %s", file2);
+ }
+ e2 = m2 + MMAP_CHUNK;
+ }
}
+ munmap(m1, MMAP_CHUNK);
+ munmap(m2, MMAP_CHUNK);
if (len1 != len2)
eofmsg (len1 > len2 ? file2 : file1);
if (dfound)
exit(DIFF_EXIT);
}
+
+static u_char *
+remmap(mem, fd, offset)
+ u_char *mem;
+ int fd;
+ off_t offset;
+{
+ if (mem != NULL)
+ munmap(mem, MMAP_CHUNK);
+ mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
+ if (mem == MAP_FAILED)
+ return (NULL);
+ madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
+ return (mem);
+}
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