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1.1 root 1: /* @(#)sno3.c 1.1 */
2: #include "sno.h"
3:
4: /*
5: * sno3
6: */
7:
8:
9: int
10: bextend (str, last)
11: struct node *str, *last;
12: {
13: register struct node *a, *s;
14: register int b;
15: struct node *cc;
16: int c, d;
17:
18: s = str;
19: if ((cc = s->p1) == 0)
20: goto bad;
21: b = d = 0;
22: a = s->p2;
23: if (a == 0) {
24: a = cc;
25: goto eb2;
26: }
27: eb1:
28: if (a == last)
29: goto bad;
30: a = a->p1;
31: eb2:
32: d++;
33: c = class (a->ch);
34: if (c == 1) { /* rp */
35: if (b == 0)
36: goto bad;
37: b--;
38: goto eb3;
39: }
40: if (c == 2) { /* lp */
41: b++;
42: goto eb1;
43: }
44: eb3:
45: if (b == 0) {
46: s->p2= a;
47: return (d);
48: }
49: goto eb1;
50: bad:
51: return (0);
52: }
53:
54: int
55: ubextend (str, last)
56: struct node *str, *last;
57: {
58: register struct node *a, *b, *s;
59:
60: s = str;
61: a = s->p1;
62: if (a == 0)
63: goto bad;
64: b = s->p2;
65: if (b == 0)
66: goto good;
67: if (b == last)
68: goto bad;
69: a = b->p1;
70: good:
71: s->p2 = a;
72: return (1);
73: bad:
74: return (0);
75: }
76:
77: struct node *
78: search (arg, r)
79: struct node *arg, *r;
80: {
81: struct node *list, *back, *str,
82: *etc, *next, *last, *base, *e;
83: register struct node *a, *b, *var;
84: int c, d;
85:
86: a = arg->p2;
87: list = base = salloc();
88: last = next = 0;
89: goto badv1;
90: badvanc:
91: a = a->p1;
92: if (a->typ == 0) {
93: list->p1 = 0;
94: if (rfail == 1) {
95: a = 0;
96: goto fail;
97: }
98: list = base;
99: if (r == 0)
100: next = last = 0;
101: else {
102: next = r->p1;
103: last = r->p2;
104: }
105: goto adv1;
106: }
107: b = salloc();
108: list->p1 = b;
109: list = b;
110: badv1:
111: list->p2 = back = salloc();
112: back->p1 = last;
113: b = a->p2;
114: c = a->typ;
115: list->typ = c;
116: if (c < 2) {
117: back->p2 = eval (b, 1);
118: goto badvanc;
119: }
120: last = list;
121: str = salloc();
122: etc = salloc();
123: back->p2 = var = salloc();
124: var->typ = b->typ;
125: var->p1 = str;
126: var->p2 = etc;
127: e = b->p1;
128: if (e == 0)
129: etc->p1 = 0;
130: else
131: etc->p1 = eval (e, 0);
132: e = b->p2;
133: if (e == 0)
134: etc->p2 = 0;
135: else {
136: e = eval (e, 1);
137: etc->p2 = (struct node *) strbin (e);
138: delete (e);
139: }
140: goto badvanc;
141:
142: retard:
143: a = back->p1;
144: if (a == 0) {
145: rfail = 1;
146: goto fail;
147: }
148: list = a;
149: back = list->p2;
150: var = back->p2;
151: str = var->p1;
152: etc = var->p2;
153: if (etc->p2)
154: goto retard;
155: if (var->typ == 1) {
156: if (bextend (str, last) == 0)
157: goto retard;
158: goto adv0;
159: }
160: if (ubextend (str, last) == 0)
161: goto retard;
162: adv0:
163: a = str->p2;
164: adv01:
165: if (a == last)
166: next = 0;
167: else
168: next = a->p1;
169: advanc:
170: a = list->p1;
171: if (a == 0) {
172: a = salloc();
173: if (r == 0) {
174: a->p1 = a->p2 = 0;
175: goto fail;
176: }
177: b = r->p1;
178: a->p1 = b;
179: if (next == 0) {
180: a->p2 = r->p2;
181: goto fail;
182: }
183: while (1) {
184: e = b->p1;
185: if (e == next) {
186: a->p2 = b;
187: goto fail;
188: }
189: b = e;
190: }
191: }
192: list = a;
193: adv1:
194: back = list->p2;
195: var = back->p2;
196: d = list->typ;
197: if (d < 2) {
198: if (var == 0)
199: goto advanc;
200: if (next == 0)
201: goto retard;
202: a = next;
203: b = var->p1;
204: e = var->p2;
205: while (1) {
206: if (a->ch != b->ch)
207: goto retard;
208: if (b == e)
209: goto adv01;
210: if (a == last)
211: goto retard;
212: a = a->p1;
213: b = b->p1;
214: }
215: }
216: str = var->p1;
217: etc = var->p2;
218: str->p1 = next;
219: str->p2 = 0;
220: c = (int) etc->p2;
221: if (var->typ == 1) {
222: d = bextend (str, last);
223: if (d == 0)
224: goto retard;
225: if (c == 0)
226: goto adv0;
227: while (1) {
228: c -= d;
229: if (c == 0)
230: goto adv0;
231: if (c < 0)
232: goto retard;
233: d = bextend (str, last);
234: if (d == 0)
235: goto retard;
236: }
237: }
238: if (c == 0) {
239: if (d==3 && next!=0) {
240: str->p2 = last;
241: goto adv0;
242: }
243: goto advanc;
244: }
245: while (c--)
246: if (ubextend (str, last) == 0)
247: goto retard;
248: goto adv0;
249:
250: fail:
251: list = base;
252: goto f1;
253: fadv:
254: sfree (back);
255: b = list->p1;
256: sfree (list);
257: if (b == 0)
258: return (a);
259: list = b;
260: f1:
261: back = list->p2;
262: var = back->p2;
263: if (list->typ < 2) {
264: delete (var);
265: goto fadv;
266: }
267: str = var->p1;
268: etc = var->p2;
269: if (a != 0 && etc->p1 != 0) {
270: if (str->p2 == 0) {
271: sfree (str);
272: str = 0;
273: }
274: assign (etc->p1, copy (str));
275: }
276: if (str)
277: sfree (str);
278: sfree (etc);
279: sfree (var);
280: goto fadv;
281: }
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