projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 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 |