The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_lex.c

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    1 /*-
    2  * Mach Operating System
    3  * Copyright (c) 1991,1990 Carnegie Mellon University
    4  * All Rights Reserved.
    5  *
    6  * Permission to use, copy, modify and distribute this software and its
    7  * documentation is hereby granted, provided that both the copyright
    8  * notice and this permission notice appear in all copies of the
    9  * software, derivative works or modified versions, and any portions
   10  * thereof, and that both notices appear in supporting documentation.
   11  *
   12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
   13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   15  *
   16  * Carnegie Mellon requests users of this software to return to
   17  *
   18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   19  *  School of Computer Science
   20  *  Carnegie Mellon University
   21  *  Pittsburgh PA 15213-3890
   22  *
   23  * any improvements or extensions that they make and grant Carnegie the
   24  * rights to redistribute these changes.
   25  */
   26 /*
   27  *      Author: David B. Golub, Carnegie Mellon University
   28  *      Date:   7/90
   29  */
   30 /*
   31  * Lexical analyzer.
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD: stable/9/sys/ddb/db_lex.c 174914 2007-12-26 09:33:19Z rwatson $");
   36 
   37 #include <sys/param.h>
   38 #include <sys/libkern.h>
   39 
   40 #include <ddb/ddb.h>
   41 #include <ddb/db_lex.h>
   42 
   43 static char     db_line[DB_MAXLINE];
   44 static char *   db_lp, *db_endlp;
   45 
   46 static int      db_lex(void);
   47 static void     db_flush_line(void);
   48 static int      db_read_char(void);
   49 static void     db_unread_char(int);
   50 
   51 int
   52 db_read_line()
   53 {
   54         int     i;
   55 
   56         i = db_readline(db_line, sizeof(db_line));
   57         if (i == 0)
   58             return (0); /* EOI */
   59         db_lp = db_line;
   60         db_endlp = db_lp + i;
   61         return (i);
   62 }
   63 
   64 /*
   65  * Simulate a line of input into DDB.
   66  */
   67 void
   68 db_inject_line(const char *command)
   69 {
   70 
   71         strlcpy(db_line, command, sizeof(db_line));
   72         db_lp = db_line;
   73         db_endlp = db_lp + strlen(command);
   74 }
   75 
   76 /*
   77  * In rare cases, we may want to pull the remainder of the line input
   78  * verbatim, rather than lexing it.  For example, when assigning literal
   79  * values associated with scripts.  In that case, return a static pointer to
   80  * the current location in the input buffer.  The caller must be aware that
   81  * the contents are not stable if other lex/input calls are made.
   82  */
   83 char *
   84 db_get_line(void)
   85 {
   86 
   87         return (db_lp);
   88 }
   89 
   90 static void
   91 db_flush_line()
   92 {
   93         db_lp = db_line;
   94         db_endlp = db_line;
   95 }
   96 
   97 static int      db_look_char = 0;
   98 
   99 static int
  100 db_read_char()
  101 {
  102         int     c;
  103 
  104         if (db_look_char != 0) {
  105             c = db_look_char;
  106             db_look_char = 0;
  107         }
  108         else if (db_lp >= db_endlp)
  109             c = -1;
  110         else
  111             c = *db_lp++;
  112         return (c);
  113 }
  114 
  115 static void
  116 db_unread_char(c)
  117         int c;
  118 {
  119         db_look_char = c;
  120 }
  121 
  122 static int      db_look_token = 0;
  123 
  124 void
  125 db_unread_token(t)
  126         int     t;
  127 {
  128         db_look_token = t;
  129 }
  130 
  131 int
  132 db_read_token()
  133 {
  134         int     t;
  135 
  136         if (db_look_token) {
  137             t = db_look_token;
  138             db_look_token = 0;
  139         }
  140         else
  141             t = db_lex();
  142         return (t);
  143 }
  144 
  145 db_expr_t       db_tok_number;
  146 char    db_tok_string[TOK_STRING_SIZE];
  147 
  148 db_expr_t       db_radix = 16;
  149 
  150 void
  151 db_flush_lex()
  152 {
  153         db_flush_line();
  154         db_look_char = 0;
  155         db_look_token = 0;
  156 }
  157 
  158 static int
  159 db_lex()
  160 {
  161         int     c;
  162 
  163         c = db_read_char();
  164         while (c <= ' ' || c > '~') {
  165             if (c == '\n' || c == -1)
  166                 return (tEOL);
  167             c = db_read_char();
  168         }
  169 
  170         if (c >= '' && c <= '9') {
  171             /* number */
  172             int r, digit = 0;
  173 
  174             if (c > '')
  175                 r = db_radix;
  176             else {
  177                 c = db_read_char();
  178                 if (c == 'O' || c == 'o')
  179                     r = 8;
  180                 else if (c == 'T' || c == 't')
  181                     r = 10;
  182                 else if (c == 'X' || c == 'x')
  183                     r = 16;
  184                 else {
  185                     r = db_radix;
  186                     db_unread_char(c);
  187                 }
  188                 c = db_read_char();
  189             }
  190             db_tok_number = 0;
  191             for (;;) {
  192                 if (c >= '' && c <= ((r == 8) ? '7' : '9'))
  193                     digit = c - '';
  194                 else if (r == 16 && ((c >= 'A' && c <= 'F') ||
  195                                      (c >= 'a' && c <= 'f'))) {
  196                     if (c >= 'a')
  197                         digit = c - 'a' + 10;
  198                     else if (c >= 'A')
  199                         digit = c - 'A' + 10;
  200                 }
  201                 else
  202                     break;
  203                 db_tok_number = db_tok_number * r + digit;
  204                 c = db_read_char();
  205             }
  206             if ((c >= '' && c <= '9') ||
  207                 (c >= 'A' && c <= 'Z') ||
  208                 (c >= 'a' && c <= 'z') ||
  209                 (c == '_'))
  210             {
  211                 db_error("Bad character in number\n");
  212                 db_flush_lex();
  213                 return (tEOF);
  214             }
  215             db_unread_char(c);
  216             return (tNUMBER);
  217         }
  218         if ((c >= 'A' && c <= 'Z') ||
  219             (c >= 'a' && c <= 'z') ||
  220             c == '_' || c == '\\')
  221         {
  222             /* string */
  223             char *cp;
  224 
  225             cp = db_tok_string;
  226             if (c == '\\') {
  227                 c = db_read_char();
  228                 if (c == '\n' || c == -1)
  229                     db_error("Bad escape\n");
  230             }
  231             *cp++ = c;
  232             while (1) {
  233                 c = db_read_char();
  234                 if ((c >= 'A' && c <= 'Z') ||
  235                     (c >= 'a' && c <= 'z') ||
  236                     (c >= '' && c <= '9') ||
  237                     c == '_' || c == '\\' || c == ':' || c == '.')
  238                 {
  239                     if (c == '\\') {
  240                         c = db_read_char();
  241                         if (c == '\n' || c == -1)
  242                             db_error("Bad escape\n");
  243                     }
  244                     *cp++ = c;
  245                     if (cp == db_tok_string+sizeof(db_tok_string)) {
  246                         db_error("String too long\n");
  247                         db_flush_lex();
  248                         return (tEOF);
  249                     }
  250                     continue;
  251                 }
  252                 else {
  253                     *cp = '\0';
  254                     break;
  255                 }
  256             }
  257             db_unread_char(c);
  258             return (tIDENT);
  259         }
  260 
  261         switch (c) {
  262             case '+':
  263                 return (tPLUS);
  264             case '-':
  265                 return (tMINUS);
  266             case '.':
  267                 c = db_read_char();
  268                 if (c == '.')
  269                     return (tDOTDOT);
  270                 db_unread_char(c);
  271                 return (tDOT);
  272             case '*':
  273                 return (tSTAR);
  274             case '/':
  275                 return (tSLASH);
  276             case '=':
  277                 return (tEQ);
  278             case '%':
  279                 return (tPCT);
  280             case '#':
  281                 return (tHASH);
  282             case '(':
  283                 return (tLPAREN);
  284             case ')':
  285                 return (tRPAREN);
  286             case ',':
  287                 return (tCOMMA);
  288             case '"':
  289                 return (tDITTO);
  290             case '$':
  291                 return (tDOLLAR);
  292             case '!':
  293                 return (tEXCL);
  294             case ';':
  295                 return (tSEMI);
  296             case '<':
  297                 c = db_read_char();
  298                 if (c == '<')
  299                     return (tSHIFT_L);
  300                 db_unread_char(c);
  301                 break;
  302             case '>':
  303                 c = db_read_char();
  304                 if (c == '>')
  305                     return (tSHIFT_R);
  306                 db_unread_char(c);
  307                 break;
  308             case -1:
  309                 return (tEOF);
  310         }
  311         db_printf("Bad character\n");
  312         db_flush_lex();
  313         return (tEOF);
  314 }

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