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+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
+ * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+/*
+ * HISTORY
+ * $Log: db_lex.c,v $
+ * Revision 1.1 1992/03/25 21:45:13 pace
+ * Initial revision
+ *
+ * Revision 2.3 91/02/05 17:06:36 mrt
+ * Changed to new Mach copyright
+ * [91/01/31 16:18:20 mrt]
+ *
+ * Revision 2.2 90/08/27 21:51:10 dbg
+ * Add 'dotdot' token.
+ * [90/08/22 dbg]
+ *
+ * Allow backslash to quote any character into an identifier.
+ * Allow colon in identifier for symbol table qualification.
+ * [90/08/16 dbg]
+ * Reduce lint.
+ * [90/08/07 dbg]
+ * Created.
+ * [90/07/25 dbg]
+ *
+ */
+/*
+ * Author: David B. Golub, Carnegie Mellon University
+ * Date: 7/90
+ */
+/*
+ * Lexical analyzer.
+ */
+#include <ddb/db_lex.h>
+
+char db_line[120];
+char * db_lp, *db_endlp;
+
+int
+db_read_line()
+{
+ int i;
+
+ i = db_readline(db_line, sizeof(db_line));
+ if (i == 0)
+ return (0); /* EOI */
+ db_lp = db_line;
+ db_endlp = db_lp + i;
+ return (i);
+}
+
+void
+db_flush_line()
+{
+ db_lp = db_line;
+ db_endlp = db_line;
+}
+
+int db_look_char = 0;
+
+int
+db_read_char()
+{
+ int c;
+
+ if (db_look_char != 0) {
+ c = db_look_char;
+ db_look_char = 0;
+ }
+ else if (db_lp >= db_endlp)
+ c = -1;
+ else
+ c = *db_lp++;
+ return (c);
+}
+
+void
+db_unread_char(c)
+{
+ db_look_char = c;
+}
+
+int db_look_token = 0;
+
+void
+db_unread_token(t)
+ int t;
+{
+ db_look_token = t;
+}
+
+int
+db_read_token()
+{
+ int t;
+
+ if (db_look_token) {
+ t = db_look_token;
+ db_look_token = 0;
+ }
+ else
+ t = db_lex();
+ return (t);
+}
+
+int db_tok_number;
+char db_tok_string[TOK_STRING_SIZE];
+
+int db_radix = 16;
+
+void
+db_flush_lex()
+{
+ db_flush_line();
+ db_look_char = 0;
+ db_look_token = 0;
+}
+
+int
+db_lex()
+{
+ int c;
+
+ c = db_read_char();
+ while (c <= ' ' || c > '~') {
+ if (c == '\n' || c == -1)
+ return (tEOL);
+ c = db_read_char();
+ }
+
+ if (c >= '0' && c <= '9') {
+ /* number */
+ int r, digit;
+
+ if (c > '0')
+ r = db_radix;
+ else {
+ c = db_read_char();
+ if (c == 'O' || c == 'o')
+ r = 8;
+ else if (c == 'T' || c == 't')
+ r = 10;
+ else if (c == 'X' || c == 'x')
+ r = 16;
+ else {
+ r = db_radix;
+ db_unread_char(c);
+ }
+ c = db_read_char();
+ }
+ db_tok_number = 0;
+ for (;;) {
+ if (c >= '0' && c <= ((r == 8) ? '7' : '9'))
+ digit = c - '0';
+ else if (r == 16 && ((c >= 'A' && c <= 'F') ||
+ (c >= 'a' && c <= 'f'))) {
+ if (c >= 'a')
+ digit = c - 'a' + 10;
+ else if (c >= 'A')
+ digit = c - 'A' + 10;
+ }
+ else
+ break;
+ db_tok_number = db_tok_number * r + digit;
+ c = db_read_char();
+ }
+ if ((c >= '0' && c <= '9') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= 'a' && c <= 'z') ||
+ (c == '_'))
+ {
+ db_error("Bad character in number\n");
+ db_flush_lex();
+ return (tEOF);
+ }
+ db_unread_char(c);
+ return (tNUMBER);
+ }
+ if ((c >= 'A' && c <= 'Z') ||
+ (c >= 'a' && c <= 'z') ||
+ c == '_' || c == '\\')
+ {
+ /* string */
+ char *cp;
+
+ cp = db_tok_string;
+ if (c == '\\') {
+ c = db_read_char();
+ if (c == '\n' || c == -1)
+ db_error("Bad escape\n");
+ }
+ *cp++ = c;
+ while (1) {
+ c = db_read_char();
+ if ((c >= 'A' && c <= 'Z') ||
+ (c >= 'a' && c <= 'z') ||
+ (c >= '0' && c <= '9') ||
+ c == '_' || c == '\\' || c == ':')
+ {
+ if (c == '\\') {
+ c = db_read_char();
+ if (c == '\n' || c == -1)
+ db_error("Bad escape\n");
+ }
+ *cp++ = c;
+ if (cp == db_tok_string+sizeof(db_tok_string)) {
+ db_error("String too long\n");
+ db_flush_lex();
+ return (tEOF);
+ }
+ continue;
+ }
+ else {
+ *cp = '\0';
+ break;
+ }
+ }
+ db_unread_char(c);
+ return (tIDENT);
+ }
+
+ switch (c) {
+ case '+':
+ return (tPLUS);
+ case '-':
+ return (tMINUS);
+ case '.':
+ c = db_read_char();
+ if (c == '.')
+ return (tDOTDOT);
+ db_unread_char(c);
+ return (tDOT);
+ case '*':
+ return (tSTAR);
+ case '/':
+ return (tSLASH);
+ case '=':
+ return (tEQ);
+ case '%':
+ return (tPCT);
+ case '#':
+ return (tHASH);
+ case '(':
+ return (tLPAREN);
+ case ')':
+ return (tRPAREN);
+ case ',':
+ return (tCOMMA);
+ case '"':
+ return (tDITTO);
+ case '$':
+ return (tDOLLAR);
+ case '!':
+ return (tEXCL);
+ case '<':
+ c = db_read_char();
+ if (c == '<')
+ return (tSHIFT_L);
+ db_unread_char(c);
+ break;
+ case '>':
+ c = db_read_char();
+ if (c == '>')
+ return (tSHIFT_R);
+ db_unread_char(c);
+ break;
+ case -1:
+ return (tEOF);
+ }
+ db_printf("Bad character\n");
+ db_flush_lex();
+ return (tEOF);
+}
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