1 /*
2 * hash.c
3 *
4 * Manage hash tables.
5 *
6 * The following functions are visible:
7 *
8 * char *mystrdup(char *); Make space and copy string
9 * Entry **newHashTable(); Create and return initialized hash table
10 * Entry *hash_add(Entry **, char *, Entry *)
11 * Entry *hash_get(Entry **, char *)
12 *
13 * SOFTWARE RIGHTS
14 *
15 * We reserve no LEGAL rights to the Purdue Compiler Construction Tool
16 * Set (PCCTS) -- PCCTS is in the public domain. An individual or
17 * company may do whatever they wish with source code distributed with
18 * PCCTS or the code generated by PCCTS, including the incorporation of
19 * PCCTS, or its output, into commerical software.
20 *
21 * We encourage users to develop software with PCCTS. However, we do ask
22 * that credit is given to us for developing PCCTS. By "credit",
23 * we mean that if you incorporate our source code into one of your
24 * programs (commercial product, research project, or otherwise) that you
25 * acknowledge this fact somewhere in the documentation, research report,
26 * etc... If you like PCCTS and have developed a nice tool with the
27 * output, please mention that you developed it using PCCTS. In
28 * addition, we ask that this header remain intact in our source code.
29 * As long as these guidelines are kept, we expect to continue enhancing
30 * this system and expect to make other tools available as they are
31 * completed.
32 *
33 * ANTLR 1.33
34 * Terence Parr
35 * Parr Research Corporation
36 * with Purdue University and AHPCRC, University of Minnesota
37 * 1989-2001
38 */
39
40 #include <stdio.h>
41 #include "pcctscfg.h"
42 #include "hash.h"
43
44 #ifdef __USE_PROTOS
45 #include <stdlib.h>
46 #else
47 #ifdef VAXC
48 #include <stdlib.h>
49 #else
50 #include <malloc.h>
51 #endif
52 #endif
53 #include <string.h>
54
55 #define StrSame 0
56
57 #define fatal(err) \
58 {fprintf(stderr, "%s(%d):", __FILE__, __LINE__); \
59 fprintf(stderr, " %s\n", err); exit(PCCTS_EXIT_FAILURE);}
60 #define require(expr, err) {if ( !(expr) ) fatal(err);}
61
62 static unsigned size = HashTableSize;
63 static char *strings = NULL;
64 static char *strp;
65 static unsigned strsize = StrTableSize;
66
67 /* create the hash table and string table for terminals (string table only once) */
68 Entry **
69 #ifdef __USE_PROTOS
newHashTable(void)70 newHashTable( void )
71 #else
72 newHashTable( )
73 #endif
74 {
75 Entry **table;
76
77 table = (Entry **) calloc(size, sizeof(Entry *));
78 require( table != NULL, "cannot allocate hash table");
79 if ( strings == NULL )
80 {
81 strings = (char *) calloc(strsize, sizeof(char));
82 require( strings != NULL, "cannot allocate string table");
83 strp = strings;
84 }
85 return table;
86 }
87
88 void
89 #ifdef __USE_PROTOS
killHashTable(Entry ** table)90 killHashTable( Entry **table )
91 #else
92 killHashTable( table )
93 Entry **table;
94 #endif
95 {
96 /* for now, just free table, forget entries */
97 free( (char *) table ); /* MR10 cast */
98 }
99
100 /* Given a table, add 'rec' with key 'key' (add to front of list). return ptr to entry */
101 Entry *
102 #ifdef __USE_PROTOS
hash_add(Entry ** table,char * key,Entry * rec)103 hash_add( Entry **table, char *key, Entry *rec )
104 #else
105 hash_add( table, key, rec )
106 Entry **table;
107 char *key;
108 Entry *rec;
109 #endif
110 {
111 unsigned h=0;
112 char *p=key;
113 require(table!=NULL && key!=NULL && rec!=NULL, "add: invalid addition");
114
115 Hash(p,h,size);
116 rec->next = table[h]; /* Add to singly-linked list */
117 table[h] = rec;
118 return rec;
119 }
120
121 /* Return ptr to 1st entry found in table under key (return NULL if none found) */
122 Entry *
123 #ifdef __USE_PROTOS
hash_get(Entry ** table,char * key)124 hash_get( Entry **table, char *key )
125 #else
126 hash_get( table, key )
127 Entry **table;
128 char *key;
129 #endif
130 {
131 unsigned h=0;
132 char *p=key;
133 Entry *q;
134 /* require(table!=NULL && key!=NULL, "get: invalid table and/or key");*/
135 if ( !(table!=NULL && key!=NULL) ) *((char *) 34) = 3;
136
137 Hash(p,h,size);
138 for (q = table[h]; q != NULL; q = q->next)
139 {
140 if ( strcmp(key, q->str) == StrSame ) return( q );
141 }
142 return( NULL );
143 }
144
145 #ifdef DEBUG_HASH
146 void
147 #ifdef __USE_PROTOS
hashStat(Entry ** table)148 hashStat( Entry **table )
149 #else
150 hashStat( table )
151 Entry **table;
152 #endif
153 {
154 static unsigned short count[20];
155 int i,n=0,low=0, hi=0;
156 Entry **p;
157 float avg=0.0;
158
159 for (i=0; i<20; i++) count[i] = 0;
160 for (p=table; p<&(table[size]); p++)
161 {
162 Entry *q = *p;
163 int len;
164
165 if ( q != NULL && low==0 ) low = p-table;
166 len = 0;
167 if ( q != NULL ) fprintf(stderr, "[%d]", p-table);
168 while ( q != NULL )
169 {
170 len++;
171 n++;
172 fprintf(stderr, " %s", q->str);
173 q = q->next;
174 if ( q == NULL ) fprintf(stderr, "\n");
175 }
176 count[len]++;
177 if ( *p != NULL ) hi = p-table;
178 }
179
180 fprintf(stderr, "Storing %d recs used %d hash positions out of %d\n",
181 n, size-count[0], size);
182 fprintf(stderr, "%f %% utilization\n",
183 ((float)(size-count[0]))/((float)size));
184 for (i=0; i<20; i++)
185 {
186 if ( count[i] != 0 )
187 {
188 avg += (((float)(i*count[i]))/((float)n)) * i;
189 fprintf(stderr, "Bucket len %d == %d (%f %% of recs)\n",
190 i, count[i], ((float)(i*count[i]))/((float)n));
191 }
192 }
193 fprintf(stderr, "Avg bucket length %f\n", avg);
194 fprintf(stderr, "Range of hash function: %d..%d\n", low, hi);
195 }
196 #endif
197
198 /* Add a string to the string table and return a pointer to it.
199 * Bump the pointer into the string table to next avail position.
200 */
201 char *
202 #ifdef __USE_PROTOS
mystrdup(char * s)203 mystrdup( char *s )
204 #else
205 mystrdup( s )
206 char *s;
207 #endif
208 {
209 char *start=strp;
210 require(s!=NULL, "mystrdup: NULL string");
211
212 while ( *s != '\0' )
213 {
214 require( strp <= &(strings[strsize-2]),
215 "string table overflow\nIncrease StrTableSize in hash.h and recompile hash.c\n");
216 *strp++ = *s++;
217 }
218 *strp++ = '\0';
219
220 return( start );
221 }
222