| 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 5.5 (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 | * User-defined commands are read into usertable. |
| 39 | */ |
| 40 | |
| 41 | #include "less.h" |
| 42 | #include "cmd.h" |
| 43 | |
| 44 | /* |
| 45 | * Command table is ordered roughly according to expected |
| 46 | * frequency of use, so the common commands are near the beginning. |
| 47 | */ |
| 48 | static char cmdtable[] = |
| 49 | { |
| 50 | '\r',0, A_F_LINE, |
| 51 | '\n',0, A_F_LINE, |
| 52 | 'e',0, A_F_LINE, |
| 53 | 'j',0, A_F_LINE, |
| 54 | CONTROL('E'),0, A_F_LINE, |
| 55 | CONTROL('N'),0, A_F_LINE, |
| 56 | 'k',0, A_B_LINE, |
| 57 | 'y',0, A_B_LINE, |
| 58 | CONTROL('Y'),0, A_B_LINE, |
| 59 | CONTROL('K'),0, A_B_LINE, |
| 60 | CONTROL('P'),0, A_B_LINE, |
| 61 | 'd',0, A_F_SCROLL, |
| 62 | CONTROL('D'),0, A_F_SCROLL, |
| 63 | 'u',0, A_B_SCROLL, |
| 64 | CONTROL('U'),0, A_B_SCROLL, |
| 65 | ' ',0, A_F_SCREEN, |
| 66 | 'f',0, A_F_SCREEN, |
| 67 | CONTROL('F'),0, A_F_SCREEN, |
| 68 | CONTROL('V'),0, A_F_SCREEN, |
| 69 | 'b',0, A_B_SCREEN, |
| 70 | CONTROL('B'),0, A_B_SCREEN, |
| 71 | CONTROL('['),'v',0, A_B_SCREEN, |
| 72 | 'R',0, A_FREPAINT, |
| 73 | 'r',0, A_REPAINT, |
| 74 | CONTROL('R'),0, A_REPAINT, |
| 75 | CONTROL('L'),0, A_REPAINT, |
| 76 | 'g',0, A_GOLINE, |
| 77 | '<',0, A_GOLINE, |
| 78 | CONTROL('['),'<',0, A_GOLINE, |
| 79 | 'p',0, A_PERCENT, |
| 80 | '%',0, A_PERCENT, |
| 81 | 'G',0, A_GOEND, |
| 82 | CONTROL('['),'>',0, A_GOEND, |
| 83 | '>',0, A_GOEND, |
| 84 | |
| 85 | '0',0, A_DIGIT, |
| 86 | '1',0, A_DIGIT, |
| 87 | '2',0, A_DIGIT, |
| 88 | '3',0, A_DIGIT, |
| 89 | '4',0, A_DIGIT, |
| 90 | '5',0, A_DIGIT, |
| 91 | '6',0, A_DIGIT, |
| 92 | '7',0, A_DIGIT, |
| 93 | '8',0, A_DIGIT, |
| 94 | '9',0, A_DIGIT, |
| 95 | |
| 96 | '=',0, A_STAT, |
| 97 | CONTROL('G'),0, A_STAT, |
| 98 | '/',0, A_F_SEARCH, |
| 99 | '?',0, A_B_SEARCH, |
| 100 | 'n',0, A_AGAIN_SEARCH, |
| 101 | 'm',0, A_SETMARK, |
| 102 | '\'',0, A_GOMARK, |
| 103 | CONTROL('X'),CONTROL('X'),0, A_GOMARK, |
| 104 | 'E',0, A_EXAMINE, |
| 105 | ':','e',0, A_EXAMINE, |
| 106 | CONTROL('X'),CONTROL('V'),0, A_EXAMINE, |
| 107 | 'N',0, A_NEXT_FILE, |
| 108 | 'P',0, A_PREV_FILE, |
| 109 | ':','n',0, A_NEXT_FILE, |
| 110 | ':','p',0, A_PREV_FILE, |
| 111 | '-',0, A_TOGGLE_OPTION, |
| 112 | '_',0, A_DISP_OPTION, |
| 113 | 'v',0, A_VISUAL, |
| 114 | '!',0, A_SHELL, |
| 115 | '+',0, A_FIRSTCMD, |
| 116 | |
| 117 | 'H',0, A_HELP, |
| 118 | 'h',0, A_HELP, |
| 119 | 'q',0, A_QUIT, |
| 120 | ':','q',0, A_QUIT, |
| 121 | 'Z','Z',0, A_QUIT |
| 122 | }; |
| 123 | |
| 124 | char *cmdendtable = cmdtable + sizeof(cmdtable); |
| 125 | |
| 126 | static char usertable[MAX_USERCMD]; |
| 127 | char *userendtable = usertable; |
| 128 | |
| 129 | static char kbuf[MAX_CMDLEN+1]; |
| 130 | static char *kp = kbuf; |
| 131 | |
| 132 | /* |
| 133 | * Decode a command character and return the associated action. |
| 134 | */ |
| 135 | public int |
| 136 | cmd_decode(c) |
| 137 | int c; |
| 138 | { |
| 139 | register int action = A_INVALID; |
| 140 | |
| 141 | /* |
| 142 | * Append the new command character to the command string in kbuf. |
| 143 | */ |
| 144 | *kp++ = c; |
| 145 | *kp = '\0'; |
| 146 | |
| 147 | /* |
| 148 | * Look first for any user-defined commands. |
| 149 | */ |
| 150 | action = cmd_search(usertable, userendtable); |
| 151 | /* |
| 152 | * If didn't find user-defined command, |
| 153 | * try the normal default commands. |
| 154 | */ |
| 155 | if (action == A_INVALID) |
| 156 | action = cmd_search(cmdtable, cmdendtable); |
| 157 | |
| 158 | if (action != A_PREFIX) |
| 159 | /* |
| 160 | * This is not a prefix character. |
| 161 | */ |
| 162 | noprefix(); |
| 163 | |
| 164 | return (action); |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Indicate that we're not in a prefix command |
| 169 | * by resetting the command buffer pointer. |
| 170 | */ |
| 171 | public void |
| 172 | noprefix() |
| 173 | { |
| 174 | kp = kbuf; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * Search a command table for the current command string (in kbuf). |
| 179 | */ |
| 180 | static int |
| 181 | cmd_search(table, endtable) |
| 182 | char *table; |
| 183 | char *endtable; |
| 184 | { |
| 185 | register char *p; |
| 186 | register char *q; |
| 187 | |
| 188 | for (p = table, q = kbuf; p < endtable; p++, q++) |
| 189 | { |
| 190 | if (*p == *q) |
| 191 | { |
| 192 | /* |
| 193 | * Current characters match. |
| 194 | * If we're at the end of the string, we've found it. |
| 195 | * Return the action code, which is the character |
| 196 | * after the null at the end of the string |
| 197 | * in the command table. |
| 198 | */ |
| 199 | if (*p == '\0') |
| 200 | return (p[1]); |
| 201 | } else if (*q == '\0') |
| 202 | { |
| 203 | /* |
| 204 | * Hit the end of the user's command, |
| 205 | * but not the end of the string in the command table. |
| 206 | * The user's command is incomplete. |
| 207 | */ |
| 208 | return (A_PREFIX); |
| 209 | } else |
| 210 | { |
| 211 | /* |
| 212 | * Not a match. |
| 213 | * Skip ahead to the next command in the |
| 214 | * command table, and reset the pointer |
| 215 | * to the user's command. |
| 216 | */ |
| 217 | while (*p++ != '\0') ; |
| 218 | q = kbuf-1; |
| 219 | } |
| 220 | } |
| 221 | /* |
| 222 | * No match found in the entire command table. |
| 223 | */ |
| 224 | return (A_INVALID); |
| 225 | } |
| 226 | |
| 227 | /* |
| 228 | * Initialize the user command table. |
| 229 | */ |
| 230 | public void |
| 231 | init_cmd() |
| 232 | { |
| 233 | char *homedir; |
| 234 | int f; |
| 235 | int n; |
| 236 | char filename[MAXPATHLEN]; |
| 237 | extern char *getenv(); |
| 238 | |
| 239 | /* |
| 240 | * Try to open "$HOME/.less" |
| 241 | * If we can't, return without doing anything. |
| 242 | */ |
| 243 | homedir = getenv("HOME"); |
| 244 | if (homedir == NULL) |
| 245 | return; |
| 246 | (void)sprintf(filename, "%s/%s", homedir, ".less"); |
| 247 | f = open(filename, O_RDONLY); |
| 248 | if (f < 0) |
| 249 | return; |
| 250 | |
| 251 | /* |
| 252 | * Read the file into the user table. |
| 253 | * {{ Minimal error checking is done here. |
| 254 | * A garbage .less file will produce strange results. |
| 255 | * To avoid a large amount of error checking code here, we |
| 256 | * rely on the lesskey program to generate a good .less file. }} |
| 257 | */ |
| 258 | n = read(f, (char *)usertable, MAX_USERCMD); |
| 259 | if (n < 3 || usertable[n-2] != '\0') |
| 260 | { |
| 261 | /* |
| 262 | * Several error cases are lumped together here: |
| 263 | * - Cannot read user file (n < 0). |
| 264 | * - User file is too short (a valid file must |
| 265 | * have at least 3 chars: one char command string, |
| 266 | * the terminating null byte, and the action byte). |
| 267 | * - The final entry in the user file is bad (it |
| 268 | * doesn't have a null byte in the proper place). |
| 269 | * Many other error cases are not caught, such as |
| 270 | * invalid format in any except the last entry, |
| 271 | * invalid action codes, command strings too long, etc. |
| 272 | */ |
| 273 | error("invalid user key file"); |
| 274 | n = 0; |
| 275 | } |
| 276 | userendtable = usertable + n; |
| 277 | close(f); |
| 278 | } |