1 /* 2 * Copyright (c) 1988 Mark Nudleman 3 * Copyright (c) 1988, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * %sccs.include.redist.c% 7 */ 8 9 #ifndef lint 10 static char sccsid[] = "@(#)decode.c 8.1 (Berkeley) 06/06/93"; 11 #endif /* not lint */ 12 13 /* 14 * Routines to decode user commands. 15 * 16 * This is all table driven. 17 * A command table is a sequence of command descriptors. 18 * Each command descriptor is a sequence of bytes with the following format: 19 * <c1><c2>...<cN><0><action> 20 * The characters c1,c2,...,cN are the command string; that is, 21 * the characters which the user must type. 22 * It is terminated by a null <0> byte. 23 * The byte after the null byte is the action code associated 24 * with the command string. 25 * 26 * The default commands are described by cmdtable. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/file.h> 31 #include <stdio.h> 32 #include <less.h> 33 34 /* 35 * Command table is ordered roughly according to expected 36 * frequency of use, so the common commands are near the beginning. 37 */ 38 #define CONTROL(c) ((c)&037) 39 40 static char cmdtable[] = { 41 '\r',0, A_F_LINE, 42 '\n',0, A_F_LINE, 43 'j',0, A_F_LINE, 44 'k',0, A_B_LINE, 45 'd',0, A_F_SCROLL, 46 CONTROL('D'),0, A_F_SCROLL, 47 'u',0, A_B_SCROLL, 48 CONTROL('U'),0, A_B_SCROLL, 49 ' ',0, A_F_SCREEN, 50 'f',0, A_F_SCREEN, 51 CONTROL('F'),0, A_F_SCREEN, 52 'b',0, A_B_SCREEN, 53 CONTROL('B'),0, A_B_SCREEN, 54 'R',0, A_FREPAINT, 55 'r',0, A_REPAINT, 56 CONTROL('L'),0, A_REPAINT, 57 'g',0, A_GOLINE, 58 'p',0, A_PERCENT, 59 '%',0, A_PERCENT, 60 'G',0, A_GOEND, 61 '0',0, A_DIGIT, 62 '1',0, A_DIGIT, 63 '2',0, A_DIGIT, 64 '3',0, A_DIGIT, 65 '4',0, A_DIGIT, 66 '5',0, A_DIGIT, 67 '6',0, A_DIGIT, 68 '7',0, A_DIGIT, 69 '8',0, A_DIGIT, 70 '9',0, A_DIGIT, 71 72 '=',0, A_STAT, 73 CONTROL('G'),0, A_STAT, 74 '/',0, A_F_SEARCH, 75 '?',0, A_B_SEARCH, 76 'n',0, A_AGAIN_SEARCH, 77 'm',0, A_SETMARK, 78 '\'',0, A_GOMARK, 79 'E',0, A_EXAMINE, 80 'N',0, A_NEXT_FILE, 81 ':','n',0, A_NEXT_FILE, 82 'P',0, A_PREV_FILE, 83 ':','p',0, A_PREV_FILE, 84 'v',0, A_VISUAL, 85 86 'h',0, A_HELP, 87 'q',0, A_QUIT, 88 ':','q',0, A_QUIT, 89 ':','t',0, A_TAGFILE, 90 ':', 'a', 0, A_FILE_LIST, 91 'Z','Z',0, A_QUIT, 92 }; 93 94 char *cmdendtable = cmdtable + sizeof(cmdtable); 95 96 #define MAX_CMDLEN 16 97 98 static char kbuf[MAX_CMDLEN+1]; 99 static char *kp = kbuf; 100 101 /* 102 * Indicate that we're not in a prefix command 103 * by resetting the command buffer pointer. 104 */ 105 noprefix() 106 { 107 kp = kbuf; 108 } 109 110 /* 111 * Decode a command character and return the associated action. 112 */ 113 cmd_decode(c) 114 int c; 115 { 116 register int action = A_INVALID; 117 118 /* 119 * Append the new command character to the command string in kbuf. 120 */ 121 *kp++ = c; 122 *kp = '\0'; 123 124 action = cmd_search(cmdtable, cmdendtable); 125 126 /* This is not a prefix character. */ 127 if (action != A_PREFIX) 128 noprefix(); 129 return(action); 130 } 131 132 /* 133 * Search a command table for the current command string (in kbuf). 134 */ 135 cmd_search(table, endtable) 136 char *table; 137 char *endtable; 138 { 139 register char *p, *q; 140 141 for (p = table, q = kbuf; p < endtable; p++, q++) { 142 if (*p == *q) { 143 /* 144 * Current characters match. 145 * If we're at the end of the string, we've found it. 146 * Return the action code, which is the character 147 * after the null at the end of the string 148 * in the command table. 149 */ 150 if (*p == '\0') 151 return(p[1]); 152 } 153 else if (*q == '\0') { 154 /* 155 * Hit the end of the user's command, 156 * but not the end of the string in the command table. 157 * The user's command is incomplete. 158 */ 159 return(A_PREFIX); 160 } else { 161 /* 162 * Not a match. 163 * Skip ahead to the next command in the 164 * command table, and reset the pointer 165 * to the user's command. 166 */ 167 while (*p++ != '\0'); 168 q = kbuf-1; 169 } 170 } 171 /* 172 * No match found in the entire command table. 173 */ 174 return(A_INVALID); 175 } 176