1 /* $NetBSD: decode.c,v 1.5 2003/10/13 14:34:25 agc Exp $ */
2
3 /*
4 * Copyright (c) 1988 Mark Nudelman
5 * Copyright (c) 1988, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 #ifndef lint
35 #if 0
36 static char sccsid[] = "@(#)decode.c 8.1 (Berkeley) 6/6/93";
37 #else
38 __RCSID("$NetBSD: decode.c,v 1.5 2003/10/13 14:34:25 agc Exp $");
39 #endif
40 #endif /* not lint */
41
42 /*
43 * Routines to decode user commands.
44 *
45 * This is all table driven.
46 * A command table is a sequence of command descriptors.
47 * Each command descriptor is a sequence of bytes with the following format:
48 * <c1><c2>...<cN><0><action>
49 * The characters c1,c2,...,cN are the command string; that is,
50 * the characters which the user must type.
51 * It is terminated by a null <0> byte.
52 * The byte after the null byte is the action code associated
53 * with the command string.
54 *
55 * The default commands are described by cmdtable.
56 */
57
58 #include <sys/param.h>
59 #include <sys/file.h>
60 #include <stdio.h>
61
62 #include "less.h"
63 #include "extern.h"
64
65 /*
66 * Command table is ordered roughly according to expected
67 * frequency of use, so the common commands are near the beginning.
68 */
69 #define CONTROL(c) ((c)&037)
70
71 static char cmdtable[] = {
72 '\r',0, A_F_LINE,
73 '\n',0, A_F_LINE,
74 'j',0, A_F_LINE,
75 'k',0, A_B_LINE,
76 'd',0, A_F_SCROLL,
77 CONTROL('D'),0, A_F_SCROLL,
78 'u',0, A_B_SCROLL,
79 CONTROL('U'),0, A_B_SCROLL,
80 ' ',0, A_F_SCREEN,
81 'f',0, A_F_SCREEN,
82 CONTROL('F'),0, A_F_SCREEN,
83 'b',0, A_B_SCREEN,
84 CONTROL('B'),0, A_B_SCREEN,
85 'R',0, A_FREPAINT,
86 'r',0, A_REPAINT,
87 CONTROL('L'),0, A_REPAINT,
88 'g',0, A_GOLINE,
89 'p',0, A_PERCENT,
90 '%',0, A_PERCENT,
91 'G',0, A_GOEND,
92 '0',0, A_DIGIT,
93 '1',0, A_DIGIT,
94 '2',0, A_DIGIT,
95 '3',0, A_DIGIT,
96 '4',0, A_DIGIT,
97 '5',0, A_DIGIT,
98 '6',0, A_DIGIT,
99 '7',0, A_DIGIT,
100 '8',0, A_DIGIT,
101 '9',0, A_DIGIT,
102
103 '=',0, A_STAT,
104 CONTROL('G'),0, A_STAT,
105 '/',0, A_F_SEARCH,
106 '?',0, A_B_SEARCH,
107 'n',0, A_AGAIN_SEARCH,
108 'm',0, A_SETMARK,
109 '\'',0, A_GOMARK,
110 'E',0, A_EXAMINE,
111 'N',0, A_NEXT_FILE,
112 ':','n',0, A_NEXT_FILE,
113 'P',0, A_PREV_FILE,
114 ':','p',0, A_PREV_FILE,
115 'v',0, A_VISUAL,
116
117 'h',0, A_HELP,
118 'q',0, A_QUIT,
119 ':','q',0, A_QUIT,
120 ':','t',0, A_TAGFILE,
121 ':', 'a', 0, A_FILE_LIST,
122 'Z','Z',0, A_QUIT,
123 };
124
125 char *cmdendtable = cmdtable + sizeof(cmdtable);
126
127 #define MAX_CMDLEN 16
128
129 static char kbuf[MAX_CMDLEN+1];
130 static char *kp = kbuf;
131
132 /*
133 * Indicate that we're not in a prefix command
134 * by resetting the command buffer pointer.
135 */
136 void
noprefix()137 noprefix()
138 {
139 kp = kbuf;
140 }
141
142 /*
143 * Decode a command character and return the associated action.
144 */
145 int
cmd_decode(c)146 cmd_decode(c)
147 int c;
148 {
149 int action = A_INVALID;
150
151 /*
152 * Append the new command character to the command string in kbuf.
153 */
154 *kp++ = c;
155 *kp = '\0';
156
157 action = cmd_search(cmdtable, cmdendtable);
158
159 /* This is not a prefix character. */
160 if (action != A_PREFIX)
161 noprefix();
162 return(action);
163 }
164
165 /*
166 * Search a command table for the current command string (in kbuf).
167 */
168 int
cmd_search(table,endtable)169 cmd_search(table, endtable)
170 char *table;
171 char *endtable;
172 {
173 char *p, *q;
174
175 for (p = table, q = kbuf; p < endtable; p++, q++) {
176 if (*p == *q) {
177 /*
178 * Current characters match.
179 * If we're at the end of the string, we've found it.
180 * Return the action code, which is the character
181 * after the null at the end of the string
182 * in the command table.
183 */
184 if (*p == '\0')
185 return(p[1]);
186 }
187 else if (*q == '\0') {
188 /*
189 * Hit the end of the user's command,
190 * but not the end of the string in the command table.
191 * The user's command is incomplete.
192 */
193 return(A_PREFIX);
194 } else {
195 /*
196 * Not a match.
197 * Skip ahead to the next command in the
198 * command table, and reset the pointer
199 * to the user's command.
200 */
201 while (*p++ != '\0');
202 q = kbuf-1;
203 }
204 }
205 /*
206 * No match found in the entire command table.
207 */
208 return(A_INVALID);
209 }
210