usr/src/tools/cscope-fast/lookup.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*      Copyright (c) 1988 AT&T */
  23 /*        All Rights Reserved   */
  24
  25
  26 /*
  27  * Copyright (c) 1999 by Sun Microsystems, Inc.
  28  * All rights reserved.
  29  */
  30
  31 #pragma ident   "%Z%%M% %I%     %E% SMI"
  32
  33 /*
  34  *      cscope - interactive C symbol cross-reference
  35  *
  36  *      keyword look-up routine for the C symbol scanner
  37  */
  38
  39 #include "global.h"
  40
  41 /* keyword text for fast testing of keywords in the scanner */
  42 char    externtext[] = "extern";
  43 char    typedeftext[] = "typedef";
  44
  45 /*
  46  * This keyword table is also used for keyword text compression.  Keywords
  47  * with an index less than the numeric value of a space are replaced with the
  48  * control character corresponding to the index, so they cannot be moved
  49  * without changing the database file version and adding compatibility code
  50  * for old databases.
  51  */
  52 struct  keystruct keyword[] = {
  53         { "#define",    ' ',    MISC,   NULL }, /* must be table entry 0 */
  54                                                 /* for old databases */
  55         { "#include",   ' ',    MISC,   NULL }, /* must be table entry 1 */
  56         { "break",      '\0',   FLOW,   NULL }, /* rarely in cross-reference */
  57         { "case",       ' ',    FLOW,   NULL },
  58         { "char",       ' ',    DECL,   NULL },
  59         { "continue",   '\0',   FLOW,   NULL }, /* rarely in cross-reference */
  60         { "default",    '\0',   FLOW,   NULL }, /* rarely in cross-reference */
  61         { "#define",    ' ',    MISC,   NULL }, /* must be table entry 7 */
  62         { "double",     ' ',    DECL,   NULL },
  63         { "\t",         '\0',   MISC,   NULL }, /* must be table entry 9 */
  64         { "\n",         '\0',   MISC,   NULL }, /* must be table entry 10 */
  65         { "else",       ' ',    FLOW,   NULL },
  66         { "enum",       ' ',    DECL,   NULL },
  67         { externtext,   ' ',    DECL,   NULL },
  68         { "float",      ' ',    DECL,   NULL },
  69         { "for",        '(',    FLOW,   NULL },
  70         { "goto",       ' ',    FLOW,   NULL },
  71         { "if",         '(',    FLOW,   NULL },
  72         { "int",        ' ',    DECL,   NULL },
  73         { "long",       ' ',    DECL,   NULL },
  74         { "register",   ' ',    DECL,   NULL },
  75         { "return",     '\0',   FLOW,   NULL },
  76         { "short",      ' ',    DECL,   NULL },
  77         { "sizeof",     '\0',   MISC,   NULL },
  78         { "static",     ' ',    DECL,   NULL },
  79         { "struct",     ' ',    DECL,   NULL },
  80         { "switch",     '(',    FLOW,   NULL },
  81         { typedeftext,  ' ',    DECL,   NULL },
  82         { "union",      ' ',    DECL,   NULL },
  83         { "unsigned",   ' ',    DECL,   NULL },
  84         { "void",       ' ',    DECL,   NULL },
  85         { "while",      '(',    FLOW,   NULL },
  86
  87         /* these keywords are not compressed */
  88         { "auto",       ' ',    DECL,   NULL },
  89         { "do",         ' ',    FLOW,   NULL },
  90         { "fortran",    ' ',    DECL,   NULL },
  91         { "const",      ' ',    DECL,   NULL },
  92         { "signed",     ' ',    DECL,   NULL },
  93         { "volatile",   ' ',    DECL,   NULL },
  94 };
  95
  96 #define KEYWORDS        (sizeof (keyword) / sizeof (struct keystruct))
  97
  98 #define HASHMOD (KEYWORDS * 2 + 1)
  99
 100 static  struct  keystruct *hashtab[HASHMOD]; /* pointer table */
 101
 102 /* put the keywords into the symbol table */
 103
 104 void
 105 initsymtab(void)
 106 {
 107         int     i, j;
 108         struct  keystruct *p;
 109
 110         for (i = 1; i < KEYWORDS; ++i) {
 111                 p = &keyword[i];
 112                 j = hash(p->text) % HASHMOD;
 113                 p->next = hashtab[j];
 114                 hashtab[j] = p;
 115         }
 116 }
 117
 118 /* see if this identifier is a keyword */
 119
 120 struct keystruct *
 121 lookup(char *ident)
 122 {
 123         struct  keystruct *p;
 124         int     c;
 125
 126         /* look up the identifier in the keyword table */
 127         for (p = hashtab[hash(ident) % HASHMOD]; p != NULL; p = p->next) {
 128                 if (strequal(ident, p->text)) {
 129                         if (compress == YES && (c = p - keyword) < ' ') {
 130                                 ident[0] = c;   /* compress the keyword */
 131                         }
 132                         return (p);
 133                 }
 134         }
 135         /* this is an identifier */
 136         return (NULL);
 137 }
 138
 139 /* form hash value for string */
 140
 141 int
 142 hash(char *s)
 143 {
 144         unsigned i;
 145
 146         for (i = 0; *s != '\0'; )
 147                 i += *s++;      /* += is faster than <<= for cscope */
 148         return (i);
 149 }