| 1 | /* |
| 2 | * Copyright (c) 1988 Mark Nudleman |
| 3 | * Copyright (c) 1988 Regents of the University of California. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms are permitted |
| 7 | * provided that the above copyright notice and this paragraph are |
| 8 | * duplicated in all such forms and that any documentation, |
| 9 | * advertising materials, and other materials related to such |
| 10 | * distribution and use acknowledge that the software was developed |
| 11 | * by Mark Nudleman and the University of California, Berkeley. The |
| 12 | * name of Mark Nudleman or the |
| 13 | * University may not be used to endorse or promote products derived |
| 14 | * from this software without specific prior written permission. |
| 15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
| 17 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 18 | */ |
| 19 | |
| 20 | #ifndef lint |
| 21 | static char sccsid[] = "@(#)decode.c 5.7 (Berkeley) %G%"; |
| 22 | #endif /* not lint */ |
| 23 | |
| 24 | /* |
| 25 | * Routines to decode user commands. |
| 26 | * |
| 27 | * This is all table driven. |
| 28 | * A command table is a sequence of command descriptors. |
| 29 | * Each command descriptor is a sequence of bytes with the following format: |
| 30 | * <c1><c2>...<cN><0><action> |
| 31 | * The characters c1,c2,...,cN are the command string; that is, |
| 32 | * the characters which the user must type. |
| 33 | * It is terminated by a null <0> byte. |
| 34 | * The byte after the null byte is the action code associated |
| 35 | * with the command string. |
| 36 | * |
| 37 | * The default commands are described by cmdtable. |
| 38 | */ |
| 39 | |
| 40 | #include <sys/param.h> |
| 41 | #include <sys/file.h> |
| 42 | #include <stdio.h> |
| 43 | #include <less.h> |
| 44 | |
| 45 | /* |
| 46 | * Command table is ordered roughly according to expected |
| 47 | * frequency of use, so the common commands are near the beginning. |
| 48 | */ |
| 49 | #define CONTROL(c) ((c)&037) |
| 50 | |
| 51 | static char cmdtable[] = { |
| 52 | '\r',0, A_F_LINE, |
| 53 | '\n',0, A_F_LINE, |
| 54 | 'j',0, A_F_LINE, |
| 55 | 'k',0, A_B_LINE, |
| 56 | 'd',0, A_F_SCROLL, |
| 57 | CONTROL('D'),0, A_F_SCROLL, |
| 58 | 'u',0, A_B_SCROLL, |
| 59 | CONTROL('U'),0, A_B_SCROLL, |
| 60 | ' ',0, A_F_SCREEN, |
| 61 | 'f',0, A_F_SCREEN, |
| 62 | CONTROL('F'),0, A_F_SCREEN, |
| 63 | 'b',0, A_B_SCREEN, |
| 64 | CONTROL('B'),0, A_B_SCREEN, |
| 65 | 'R',0, A_FREPAINT, |
| 66 | 'r',0, A_REPAINT, |
| 67 | CONTROL('L'),0, A_REPAINT, |
| 68 | 'g',0, A_GOLINE, |
| 69 | 'p',0, A_PERCENT, |
| 70 | '%',0, A_PERCENT, |
| 71 | 'G',0, A_GOEND, |
| 72 | '0',0, A_DIGIT, |
| 73 | '1',0, A_DIGIT, |
| 74 | '2',0, A_DIGIT, |
| 75 | '3',0, A_DIGIT, |
| 76 | '4',0, A_DIGIT, |
| 77 | '5',0, A_DIGIT, |
| 78 | '6',0, A_DIGIT, |
| 79 | '7',0, A_DIGIT, |
| 80 | '8',0, A_DIGIT, |
| 81 | '9',0, A_DIGIT, |
| 82 | |
| 83 | '=',0, A_STAT, |
| 84 | CONTROL('G'),0, A_STAT, |
| 85 | '/',0, A_F_SEARCH, |
| 86 | '?',0, A_B_SEARCH, |
| 87 | 'n',0, A_AGAIN_SEARCH, |
| 88 | 'm',0, A_SETMARK, |
| 89 | '\'',0, A_GOMARK, |
| 90 | 'E',0, A_EXAMINE, |
| 91 | 'N',0, A_NEXT_FILE, |
| 92 | ':','n',0, A_NEXT_FILE, |
| 93 | 'P',0, A_PREV_FILE, |
| 94 | ':','p',0, A_PREV_FILE, |
| 95 | 'v',0, A_VISUAL, |
| 96 | |
| 97 | 'h',0, A_HELP, |
| 98 | 'q',0, A_QUIT, |
| 99 | ':','q',0, A_QUIT, |
| 100 | ':','t',0, A_TAGFILE, |
| 101 | ':', 'a', 0, A_FILE_LIST, |
| 102 | 'Z','Z',0, A_QUIT, |
| 103 | }; |
| 104 | |
| 105 | char *cmdendtable = cmdtable + sizeof(cmdtable); |
| 106 | |
| 107 | #define MAX_CMDLEN 16 |
| 108 | |
| 109 | static char kbuf[MAX_CMDLEN+1]; |
| 110 | static char *kp = kbuf; |
| 111 | |
| 112 | /* |
| 113 | * Indicate that we're not in a prefix command |
| 114 | * by resetting the command buffer pointer. |
| 115 | */ |
| 116 | noprefix() |
| 117 | { |
| 118 | kp = kbuf; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Decode a command character and return the associated action. |
| 123 | */ |
| 124 | cmd_decode(c) |
| 125 | int c; |
| 126 | { |
| 127 | register int action = A_INVALID; |
| 128 | |
| 129 | /* |
| 130 | * Append the new command character to the command string in kbuf. |
| 131 | */ |
| 132 | *kp++ = c; |
| 133 | *kp = '\0'; |
| 134 | |
| 135 | action = cmd_search(cmdtable, cmdendtable); |
| 136 | |
| 137 | /* This is not a prefix character. */ |
| 138 | if (action != A_PREFIX) |
| 139 | noprefix(); |
| 140 | return(action); |
| 141 | } |
| 142 | |
| 143 | /* |
| 144 | * Search a command table for the current command string (in kbuf). |
| 145 | */ |
| 146 | static |
| 147 | cmd_search(table, endtable) |
| 148 | char *table; |
| 149 | char *endtable; |
| 150 | { |
| 151 | register char *p, *q; |
| 152 | |
| 153 | for (p = table, q = kbuf; p < endtable; p++, q++) { |
| 154 | if (*p == *q) { |
| 155 | /* |
| 156 | * Current characters match. |
| 157 | * If we're at the end of the string, we've found it. |
| 158 | * Return the action code, which is the character |
| 159 | * after the null at the end of the string |
| 160 | * in the command table. |
| 161 | */ |
| 162 | if (*p == '\0') |
| 163 | return(p[1]); |
| 164 | } |
| 165 | else if (*q == '\0') { |
| 166 | /* |
| 167 | * Hit the end of the user's command, |
| 168 | * but not the end of the string in the command table. |
| 169 | * The user's command is incomplete. |
| 170 | */ |
| 171 | return(A_PREFIX); |
| 172 | } else { |
| 173 | /* |
| 174 | * Not a match. |
| 175 | * Skip ahead to the next command in the |
| 176 | * command table, and reset the pointer |
| 177 | * to the user's command. |
| 178 | */ |
| 179 | while (*p++ != '\0'); |
| 180 | q = kbuf-1; |
| 181 | } |
| 182 | } |
| 183 | /* |
| 184 | * No match found in the entire command table. |
| 185 | */ |
| 186 | return(A_INVALID); |
| 187 | } |