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1 | /*- |
2 | * Copyright (c) 1980 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * %sccs.include.redist.c% | |
252367af | 6 | */ |
d3e5ef98 | 7 | |
72fbef68 | 8 | #ifndef lint |
0fc6e47b KB |
9 | static char sccsid[] = "@(#)tree.c 5.2 (Berkeley) %G%"; |
10 | #endif /* not lint */ | |
d3e5ef98 PK |
11 | |
12 | #include "whoami.h" | |
13 | #include "0.h" | |
14 | ||
15 | /* | |
16 | * TREE SPACE DECLARATIONS | |
17 | */ | |
18 | struct tr { | |
19 | int *tr_low; | |
20 | int *tr_high; | |
21 | } ttab[MAXTREE], *tract; | |
22 | ||
23 | /* | |
24 | * The variable space is the | |
25 | * absolute base of the tree segments. | |
26 | * (exactly the same as ttab[0].tr_low) | |
27 | * Spacep is maintained to point at the | |
28 | * beginning of the next tree slot to | |
29 | * be allocated for use by the grammar. | |
30 | * Spacep is used "extern" by the semantic | |
31 | * actions in pas.y. | |
32 | * The variable tract is maintained to point | |
33 | * at the tree segment out of which we are | |
34 | * allocating (the active segment). | |
35 | */ | |
36 | int *space, *spacep; | |
37 | ||
38 | /* | |
39 | * TREENMAX is the maximum width | |
40 | * in words that any tree node | |
41 | * due to the way in which the parser uses | |
42 | * the pointer spacep. | |
43 | */ | |
44 | #define TREENMAX 6 | |
45 | ||
46 | int trspace[ITREE]; | |
47 | int *space = trspace; | |
48 | int *spacep = trspace; | |
49 | struct tr *tract = ttab; | |
50 | ||
51 | /* | |
52 | * Inittree allocates the first tree slot | |
53 | * and sets up the first segment descriptor. | |
54 | * A lot of this work is actually done statically | |
55 | * above. | |
56 | */ | |
57 | inittree() | |
58 | { | |
59 | ||
60 | ttab[0].tr_low = space; | |
61 | ttab[0].tr_high = &space[ITREE]; | |
62 | } | |
63 | ||
64 | /* | |
65 | * Tree builds the nodes in the | |
66 | * parse tree. It is rarely called | |
67 | * directly, rather calls are made | |
68 | * to tree[12345] which supplies the | |
69 | * first argument to save space in | |
70 | * the code. Tree also guarantees | |
71 | * that spacep points to the beginning | |
72 | * of the next slot it will return, | |
73 | * a property required by the parser | |
74 | * which was always true before we | |
75 | * segmented the tree space. | |
76 | */ | |
b850626e | 77 | /*VARARGS1*/ |
72fbef68 RT |
78 | struct tnode * |
79 | tree(cnt, a) | |
d3e5ef98 PK |
80 | int cnt; |
81 | { | |
82 | register int *p, *q; | |
83 | register int i; | |
84 | ||
85 | i = cnt; | |
86 | p = spacep; | |
87 | q = &a; | |
88 | do | |
89 | *p++ = *q++; | |
90 | while (--i); | |
91 | q = spacep; | |
92 | spacep = p; | |
93 | if (p+TREENMAX >= tract->tr_high) | |
94 | /* | |
95 | * this peek-ahead should | |
96 | * save a great number of calls | |
97 | * to tralloc. | |
98 | */ | |
99 | tralloc(TREENMAX); | |
72fbef68 | 100 | return ((struct tnode *) q); |
d3e5ef98 PK |
101 | } |
102 | ||
103 | /* | |
104 | * Tralloc preallocates enough | |
105 | * space in the tree to allow | |
106 | * the grammar to use the variable | |
107 | * spacep, as it did before the | |
108 | * tree was segmented. | |
109 | */ | |
110 | tralloc(howmuch) | |
111 | { | |
112 | register char *cp; | |
113 | register i; | |
114 | ||
115 | if (spacep + howmuch >= tract->tr_high) { | |
116 | i = TRINC; | |
72fbef68 | 117 | cp = malloc((unsigned) (i * sizeof ( int ))); |
df51413a | 118 | if (cp == 0) { |
d3e5ef98 PK |
119 | yerror("Ran out of memory (tralloc)"); |
120 | pexit(DIED); | |
121 | } | |
72fbef68 | 122 | spacep = (int *) cp; |
d3e5ef98 PK |
123 | tract++; |
124 | if (tract >= &ttab[MAXTREE]) { | |
125 | yerror("Ran out of tree tables"); | |
126 | pexit(DIED); | |
127 | } | |
72fbef68 | 128 | tract->tr_low = (int *) cp; |
d3e5ef98 PK |
129 | tract->tr_high = tract->tr_low+i; |
130 | } | |
131 | } | |
132 | ||
133 | extern int yylacnt; | |
72fbef68 | 134 | extern struct B *bottled; |
d3e5ef98 PK |
135 | #ifdef PXP |
136 | #endif | |
137 | /* | |
138 | * Free up the tree segments | |
139 | * at the end of a block. | |
140 | * If there is scanner lookahead, | |
141 | * i.e. if yylacnt != 0 or there is bottled output, then we | |
142 | * cannot free the tree space. | |
143 | * This happens only when errors | |
144 | * occur and the forward move extends | |
145 | * across "units". | |
146 | */ | |
147 | trfree() | |
148 | { | |
149 | ||
150 | if (yylacnt != 0 || bottled != NIL) | |
151 | return; | |
152 | #ifdef PXP | |
153 | if (needtree()) | |
154 | return; | |
155 | #endif | |
156 | spacep = space; | |
157 | while (tract->tr_low > spacep || tract->tr_high <= spacep) { | |
72fbef68 | 158 | free((char *) tract->tr_low); |
d3e5ef98 PK |
159 | tract->tr_low = NIL; |
160 | tract->tr_high = NIL; | |
161 | tract--; | |
162 | if (tract < ttab) | |
163 | panic("ttab"); | |
164 | } | |
165 | #ifdef PXP | |
166 | packtree(); | |
167 | #endif | |
168 | } | |
169 | ||
170 | /* | |
171 | * Copystr copies a token from | |
172 | * the "token" buffer into the | |
173 | * tree space. | |
174 | */ | |
175 | copystr(token) | |
176 | register char *token; | |
177 | { | |
178 | register char *cp; | |
179 | register int i; | |
180 | ||
181 | i = (strlen(token) + sizeof ( int )) & ~( ( sizeof ( int ) ) - 1 ); | |
182 | tralloc(i / sizeof ( int )); | |
72fbef68 RT |
183 | (void) pstrcpy((char *) spacep, token); |
184 | cp = (char *) spacep; | |
185 | spacep = ((int *) cp + i); | |
d3e5ef98 | 186 | tralloc(TREENMAX); |
72fbef68 | 187 | return ((int) cp); |
d3e5ef98 | 188 | } |