Commit | Line | Data |
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15637ed4 RG |
1 | /* |
2 | * Ascii magic -- file types that we know based on keywords | |
3 | * that can appear anywhere in the file. | |
4 | * | |
5 | * Copyright (c) Ian F. Darwin, 1987. | |
6 | * Written by Ian F. Darwin. | |
7 | * | |
8 | * This software is not subject to any license of the American Telephone | |
9 | * and Telegraph Company or of the Regents of the University of California. | |
10 | * | |
11 | * Permission is granted to anyone to use this software for any purpose on | |
12 | * any computer system, and to alter it and redistribute it freely, subject | |
13 | * to the following restrictions: | |
14 | * | |
15 | * 1. The author is not responsible for the consequences of use of this | |
16 | * software, no matter how awful, even if they arise from flaws in it. | |
17 | * | |
18 | * 2. The origin of this software must not be misrepresented, either by | |
19 | * explicit claim or by omission. Since few users ever read sources, | |
20 | * credits must appear in the documentation. | |
21 | * | |
22 | * 3. Altered versions must be plainly marked as such, and must not be | |
23 | * misrepresented as being the original software. Since few users | |
24 | * ever read sources, credits must appear in the documentation. | |
25 | * | |
26 | * 4. This notice may not be removed or altered. | |
27 | */ | |
28 | ||
29 | #include <stdio.h> | |
286a6f32 | 30 | #include <string.h> |
15637ed4 | 31 | #include <ctype.h> |
286a6f32 C |
32 | #include <stdlib.h> |
33 | #include <unistd.h> | |
15637ed4 RG |
34 | #include "file.h" |
35 | #include "names.h" | |
36 | ||
37 | #ifndef lint | |
38 | static char *moduleid = | |
286a6f32 | 39 | "@(#)ascmagic.c,v 1.2 1993/06/10 00:38:04 jtc Exp"; |
15637ed4 RG |
40 | #endif /* lint */ |
41 | ||
15637ed4 RG |
42 | /* an optimisation over plain strcmp() */ |
43 | #define STREQ(a, b) (*(a) == *(b) && strcmp((a), (b)) == 0) | |
44 | ||
286a6f32 C |
45 | int |
46 | ascmagic(buf, nbytes) | |
47 | unsigned char *buf; | |
48 | int nbytes; /* size actually read */ | |
15637ed4 | 49 | { |
286a6f32 C |
50 | int i, isblock, has_escapes = 0; |
51 | unsigned char *s; | |
52 | char nbuf[HOWMANY+1]; /* one extra for terminating '\0' */ | |
53 | char *token; | |
15637ed4 | 54 | register struct names *p; |
15637ed4 RG |
55 | |
56 | /* these are easy, do them first */ | |
57 | ||
58 | /* | |
286a6f32 | 59 | * for troff, look for . + letter + letter or .\"; |
15637ed4 RG |
60 | * this must be done to disambiguate tar archives' ./file |
61 | * and other trash from real troff input. | |
62 | */ | |
286a6f32 C |
63 | if (*buf == '.') { |
64 | unsigned char *tp = buf + 1; | |
65 | ||
66 | while (isascii(*tp) && isspace(*tp)) | |
67 | ++tp; /* skip leading whitespace */ | |
68 | if ((isascii(*tp) && (isalnum(*tp) || *tp=='\\') && | |
69 | isascii(*(tp+1)) && (isalnum(*(tp+1)) || *tp=='"'))) { | |
70 | ckfputs("troff or preprocessor input text", stdout); | |
71 | return 1; | |
72 | } | |
15637ed4 RG |
73 | } |
74 | if ((*buf == 'c' || *buf == 'C') && | |
75 | isascii(*(buf + 1)) && isspace(*(buf + 1))) { | |
76 | ckfputs("fortran program text", stdout); | |
77 | return 1; | |
78 | } | |
79 | ||
80 | /* look for tokens from names.h - this is expensive! */ | |
286a6f32 C |
81 | /* make a copy of the buffer here because strtok() will destroy it */ |
82 | s = (unsigned char*) memcpy(nbuf, buf, HOWMANY); | |
83 | has_escapes = (memchr(s, '\033', HOWMANY) != NULL); | |
84 | while ((token = strtok((char*)s, " \t\n\r\f")) != NULL) { | |
15637ed4 RG |
85 | s = NULL; /* make strtok() keep on tokin' */ |
86 | for (p = names; p < names + NNAMES; p++) { | |
87 | if (STREQ(p->name, token)) { | |
88 | ckfputs(types[p->type], stdout); | |
286a6f32 C |
89 | if (has_escapes) |
90 | ckfputs(" (with escape sequences)", | |
91 | stdout); | |
15637ed4 RG |
92 | return 1; |
93 | } | |
94 | } | |
95 | } | |
96 | ||
97 | switch (is_tar(buf)) { | |
98 | case 1: | |
99 | ckfputs("tar archive", stdout); | |
100 | return 1; | |
101 | case 2: | |
102 | ckfputs("POSIX tar archive", stdout); | |
103 | return 1; | |
104 | } | |
105 | ||
286a6f32 C |
106 | if (i = is_compress(buf, &isblock)) { |
107 | if (zflag) { | |
108 | unsigned char *newbuf; | |
109 | int newsize; | |
110 | ||
111 | if (newsize = uncompress(buf, &newbuf, nbytes)) { | |
112 | tryit(newbuf, newsize); | |
113 | free(newbuf); | |
114 | } | |
115 | printf(" (%scompressed data - %d bits)", | |
116 | isblock ? "block " : "", i); | |
117 | } | |
118 | else printf("%scompressed data - %d bits", | |
119 | isblock ? "block " : "", i); | |
120 | return 1; | |
121 | } | |
122 | ||
15637ed4 RG |
123 | for (i = 0; i < nbytes; i++) { |
124 | if (!isascii(*(buf+i))) | |
125 | return 0; /* not all ascii */ | |
15637ed4 RG |
126 | } |
127 | ||
128 | /* all else fails, but it is ascii... */ | |
286a6f32 C |
129 | ckfputs("ascii text", stdout); |
130 | if (has_escapes) { | |
131 | ckfputs(" (with escape sequences)", stdout); | |
132 | } | |
15637ed4 RG |
133 | return 1; |
134 | } | |
135 | ||
136 |