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15637ed4 RG |
1 | /* |
2 | * regsub | |
3 | * | |
4 | * Copyright (c) 1986 by University of Toronto. | |
5 | * Written by Henry Spencer. Not derived from licensed software. | |
6 | * | |
7 | * Permission is granted to anyone to use this software for any | |
8 | * purpose on any computer system, and to redistribute it freely, | |
9 | * subject to the following restrictions: | |
10 | * | |
11 | * 1. The author is not responsible for the consequences of use of | |
12 | * this software, no matter how awful, even if they arise | |
13 | * from defects in it. | |
14 | * | |
15 | * 2. The origin of this software must not be misrepresented, either | |
16 | * by explicit claim or by omission. | |
17 | * | |
18 | * 3. Altered versions must be plainly marked as such, and must not | |
19 | * be misrepresented as being the original software. | |
20 | */ | |
21 | #include <regexp.h> | |
22 | #include <stdio.h> | |
23 | #include <string.h> | |
24 | #include "regmagic.h" | |
25 | ||
26 | #ifndef CHARBITS | |
27 | #define UCHARAT(p) ((int)*(unsigned char *)(p)) | |
28 | #else | |
29 | #define UCHARAT(p) ((int)*(p)&CHARBITS) | |
30 | #endif | |
31 | ||
32 | /* | |
33 | - regsub - perform substitutions after a regexp match | |
34 | */ | |
35 | void | |
36 | regsub(prog, source, dest) | |
37 | const regexp *prog; | |
38 | const char *source; | |
39 | char *dest; | |
40 | { | |
41 | register char *src; | |
42 | register char *dst; | |
43 | register char c; | |
44 | register int no; | |
45 | register int len; | |
46 | extern char *strncpy(); | |
47 | ||
48 | if (prog == NULL || source == NULL || dest == NULL) { | |
49 | regerror("NULL parm to regsub"); | |
50 | return; | |
51 | } | |
52 | if (UCHARAT(prog->program) != MAGIC) { | |
53 | regerror("damaged regexp fed to regsub"); | |
54 | return; | |
55 | } | |
56 | ||
57 | src = (char *)source; | |
58 | dst = dest; | |
59 | while ((c = *src++) != '\0') { | |
60 | if (c == '&') | |
61 | no = 0; | |
62 | else if (c == '\\' && '0' <= *src && *src <= '9') | |
63 | no = *src++ - '0'; | |
64 | else | |
65 | no = -1; | |
66 | if (no < 0) { /* Ordinary character. */ | |
67 | if (c == '\\' && (*src == '\\' || *src == '&')) | |
68 | c = *src++; | |
69 | *dst++ = c; | |
70 | } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) { | |
71 | len = prog->endp[no] - prog->startp[no]; | |
72 | (void) strncpy(dst, prog->startp[no], len); | |
73 | dst += len; | |
74 | if (len != 0 && *(dst-1) == '\0') { /* strncpy hit NUL. */ | |
75 | regerror("damaged match string"); | |
76 | return; | |
77 | } | |
78 | } | |
79 | } | |
80 | *dst++ = '\0'; | |
81 | } |