Commit | Line | Data |
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2791ff57 | 1 | /*- |
eb035710 KB |
2 | * Copyright (c) 1980, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
2791ff57 KB |
4 | * |
5 | * %sccs.include.proprietary.c% | |
6 | */ | |
7 | ||
8 | #ifndef lint | |
eb035710 | 9 | static char sccsid[] = "@(#)ex_tagio.c 8.1 (Berkeley) %G%"; |
2791ff57 | 10 | #endif /* not lint */ |
b2e575b2 JB |
11 | |
12 | /* | |
13 | * These routines are for faster tag lookup. They support the binary | |
14 | * search used in tagfind() instead of the linear search. The speedup | |
15 | * is quite noticable looking for a tag at the end of a long tags | |
16 | * file. Define FASTTAG in the Makefile to use these routines. | |
17 | */ | |
b2e575b2 | 18 | #ifdef FASTTAG |
b2e575b2 | 19 | |
5a6c967e | 20 | #ifndef vms |
b2e575b2 | 21 | #include <sys/file.h> |
5a6c967e CH |
22 | #else |
23 | #include <file.h> | |
24 | #endif | |
b2e575b2 JB |
25 | #include "ex.h" |
26 | ||
27 | static long offset = -1; | |
28 | static long block = -1; | |
29 | static int bcnt = 0; | |
30 | static int b_size = MAXBSIZE; | |
31 | static char *ibuf; | |
32 | ||
33 | topen(file, buf) | |
34 | char *file, *buf; | |
35 | { | |
36 | int fd; | |
37 | struct stat statb; | |
38 | ||
39 | offset = -1; | |
40 | block = -1; | |
41 | if ((fd = open(file, O_RDONLY, 0)) < 0) | |
42 | return(-1); | |
43 | if (fstat(fd, &statb) < 0) { | |
44 | (void)close(fd); | |
45 | return(-1); | |
46 | } | |
47 | ibuf = buf; | |
48 | b_size = statb.st_blksize; | |
49 | return(fd); | |
50 | } | |
51 | ||
52 | tseek(fd, off) | |
53 | int fd; | |
54 | long off; | |
55 | { | |
56 | int nblock; | |
57 | ||
58 | nblock = off / b_size * b_size; | |
59 | offset = off % b_size; | |
60 | if (nblock == block) | |
61 | return(0); | |
62 | block = nblock; | |
63 | if (lseek(fd, nblock, L_SET) < 0) | |
64 | return(-1); | |
65 | if ((bcnt = read(fd, ibuf, b_size)) < 0) | |
66 | return(-1); | |
67 | return(0); | |
68 | } | |
69 | ||
70 | tgets(buf, cnt, fd) | |
71 | register char *buf; | |
72 | int cnt; | |
73 | int fd; | |
74 | { | |
75 | register char *cp; | |
76 | register cc; | |
77 | ||
78 | cc = offset; | |
79 | if (cc == -1) { | |
80 | if ((bcnt = read(fd, ibuf, b_size)) <= 0) | |
81 | return (NULL); | |
82 | cc = 0; | |
83 | block = 0; | |
84 | } | |
85 | if (bcnt == 0) /* EOF */ | |
86 | return(NULL); | |
87 | cp = ibuf + cc; | |
88 | while (--cnt > 0) { | |
89 | if (++cc > bcnt) { | |
fa104d3b | 90 | block += b_size; |
b2e575b2 JB |
91 | if ((bcnt = read(fd, ibuf, b_size)) <= 0) { |
92 | offset = cc; | |
93 | return (NULL); | |
94 | } | |
b2e575b2 JB |
95 | cp = ibuf; |
96 | cc = 1; | |
97 | } | |
98 | if ((*buf++ = *cp++) == '\n') | |
99 | break; | |
100 | } | |
101 | *--buf = NULL; | |
102 | offset = cc; | |
103 | return(1); | |
104 | } | |
105 | ||
106 | tclose(fd) | |
107 | int fd; | |
108 | { | |
109 | (void)close(fd); | |
110 | offset = -1; | |
111 | block = -1; | |
112 | bcnt = 0; | |
113 | } | |
114 | #endif |