diff options
| -rw-r--r-- | usr.bin/cmp/regular.c | 66 |
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); +} |
