1 #include "e.h"
2 #include "y.tab.h"
3 #include <ctype.h>
4 
5 Infile	infile[10];
6 Infile	*curfile = infile;
7 
8 #define	MAXSRC	50
9 Src	src[MAXSRC];	/* input source stack */
10 Src	*srcp	= src;
11 
12 extern int getarg(char *);
13 extern	void eprint(void);
14 
15 void pushsrc(int type, char *ptr)	/* new input source */
16 {
17 	if (++srcp >= src + MAXSRC)
18 		ERROR "inputs nested too deep" FATAL;
19 	srcp->type = type;
20 	srcp->sp = ptr;
21 	if (dbg > 1) {
22 		printf("\n%3ld ", (long)(srcp - src));
23 		switch (srcp->type) {
24 		case File:
25 			printf("push file %s\n", ((Infile *)ptr)->fname);
26 			break;
27 		case Macro:
28 			printf("push macro <%s>\n", ptr);
29 			break;
30 		case Char:
31 			printf("push char <%c>\n", *ptr);
32 			break;
33 		case String:
34 			printf("push string <%s>\n", ptr);
35 			break;
36 		case Free:
37 			printf("push free <%s>\n", ptr);
38 			break;
39 		default:
40 			ERROR "pushed bad type %d\n", srcp->type FATAL;
41 		}
42 	}
43 }
44 
45 void popsrc(void)	/* restore an old one */
46 {
47 	if (srcp <= src)
48 		ERROR "too many inputs popped" FATAL;
49 	if (dbg > 1) {
50 		printf("%3ld ", (long)(srcp - src));
51 		switch (srcp->type) {
52 		case File:
53 			printf("pop file\n");
54 			break;
55 		case Macro:
56 			printf("pop macro\n");
57 			break;
58 		case Char:
59 			printf("pop char <%c>\n", *srcp->sp);
60 			break;
61 		case String:
62 			printf("pop string\n");
63 			break;
64 		case Free:
65 			printf("pop free\n");
66 			break;
67 		default:
68 			ERROR "pop weird input %d\n", srcp->type FATAL;
69 		}
70 	}
71 	srcp--;
72 }
73 
74 Arg	args[10];	/* argument frames */
75 Arg	*argfp = args;	/* frame pointer */
76 int	argcnt;		/* number of arguments seen so far */
77 
78 void dodef(tbl *stp)	/* collect args and switch input to defn */
79 {
80 	int i, len;
81 	char *p;
82 	Arg *ap;
83 
84 	ap = argfp+1;
85 	if (ap >= args+10)
86 		ERROR "more than arguments\n" FATAL;
87 	argcnt = 0;
88 	if (input() != '(')
89 		ERROR "disaster in dodef\n"FATAL;
90 	if (ap->argval == 0)
91 		ap->argval = malloc(1000);
92 	for (p = ap->argval; (len = getarg(p)) != -1; p += len) {
93 		ap->argstk[argcnt++] = p;
94 		if (input() == ')')
95 			break;
96 	}
97 	for (i = argcnt; i < MAXARGS; i++)
98 		ap->argstk[i] = "";
99 	if (dbg)
100 		for (i = 0; i < argcnt; i++)
101 			printf("arg %ld.%d = <%s>\n", (long)(ap-args), i+1, ap->argstk[i]);
102 	argfp = ap;
103 	pushsrc(Macro, stp->cval);
104 }
105 
106 int
107 getarg(char *p)	/* pick up single argument, store in p, return length */
108 {
109 	int n, c, npar;
110 
111 	n = npar = 0;
112 	for ( ;; ) {
113 		c = input();
114 		if (c == EOF)
115 			ERROR "end of file in getarg!\n" FATAL;
116 		if (npar == 0 && (c == ',' || c == ')'))
117 			break;
118 		if (c == '"')	/* copy quoted stuff intact */
119 			do {
120 				*p++ = c;
121 				n++;
122 			} while ((c = input()) != '"' && c != EOF);
123 		else if (c == '(')
124 			npar++;
125 		else if (c == ')')
126 			npar--;
127 		n++;
128 		*p++ = c;
129 	}
130 	*p = 0;
131 	unput(c);
132 	return(n + 1);
133 }
134 
135 #define	PBSIZE	2000
136 char	pbuf[PBSIZE];		/* pushback buffer */
137 char	*pb	= pbuf-1;	/* next pushed back character */
138 
139 char	ebuf[200];		/* collect input here for error reporting */
140 char	*ep	= ebuf;
141 
142 int
143 input(void)
144 {
145 	register int c = 0;
146 
147   loop:
148 	switch (srcp->type) {
149 	case File:
150 		c = getc(curfile->fin);
151 		if (c == EOF) {
152 			if (curfile == infile)
153 				break;
154 			if (curfile->fin != stdin) {
155 				fclose(curfile->fin);
156 				free(curfile->fname);	/* assumes allocated */
157 			}
158 			curfile--;
159 			printf(".lf %d %s\n", curfile->lineno, curfile->fname);
160 			popsrc();
161 			goto loop;
162 		}
163 		if (c == '\n')
164 			curfile->lineno++;
165 		break;
166 	case Char:
167 		if (pb >= pbuf) {
168 			c = *pb--;
169 			popsrc();
170 			break;
171 		} else {	/* can't happen? */
172 			popsrc();
173 			goto loop;
174 		}
175 	case String:
176 		c = *srcp->sp++;
177 		if (c == '\0') {
178 			popsrc();
179 			goto loop;
180 		} else {
181 			if (*srcp->sp == '\0')	/* empty, so pop */
182 				popsrc();
183 			break;
184 		}
185 	case Macro:
186 		c = *srcp->sp++;
187 		if (c == '\0') {
188 			if (--argfp < args)
189 				ERROR "argfp underflow" FATAL;
190 			popsrc();
191 			goto loop;
192 		} else if (c == '$' && isdigit((unsigned char)*srcp->sp)) {
193 			int n = 0;
194 			while (isdigit((unsigned char)*srcp->sp))
195 				n = 10 * n + *srcp->sp++ - '0';
196 			if (n > 0 && n <= MAXARGS)
197 				pushsrc(String, argfp->argstk[n-1]);
198 			goto loop;
199 		}
200 		break;
201 	case Free:	/* free string */
202 		free(srcp->sp);
203 		popsrc();
204 		goto loop;
205 	}
206 	if (ep >= ebuf + sizeof ebuf)
207 		ep = ebuf;
208 	*ep++ = c;
209 	return c;
210 }
211 
212 int
213 unput(int c)
214 {
215 	if (++pb >= pbuf + sizeof pbuf)
216 		ERROR "pushback overflow\n"FATAL;
217 	if (--ep < ebuf)
218 		ep = ebuf + sizeof(ebuf) - 1;
219 	*pb = c;
220 	pushsrc(Char, pb);
221 	return c;
222 }
223 
224 void pbstr(char *s)
225 {
226 	pushsrc(String, s);
227 }
228 
229 void error(int die, char *s)
230 {
231 	extern char *cmdname;
232 
233 	if (synerr)
234 		return;
235 	fprintf(stderr, "%s: %s", cmdname, s);
236 	if (errno > 0)
237 		perror("???");
238 	if (curfile->fin)
239 		fprintf(stderr, " near %s:%d",
240 			curfile->fname, curfile->lineno+1);
241 	fprintf(stderr, "\n");
242 	eprint();
243 	synerr = 1;
244 	errno = 0;
245 	if (die) {
246 		if (dbg)
247 			abort();
248 		else
249 			exit(1);
250 	}
251 }
252 
253 void yyerror(char *s)
254 {
255 	error(0, s);	/* temporary */
256 }
257 
258 char errbuf[2000];
259 
260 void eprint(void)	/* try to print context around error */
261 {
262 	char *p, *q;
263 
264 	if (ep == ebuf)
265 		return;				/* no context */
266 	p = ep - 1;
267 	if (p > ebuf && *p == '\n')
268 		p--;
269 	for ( ; p >= ebuf && *p != '\n'; p--)
270 		;
271 	while (*p == '\n')
272 		p++;
273 	fprintf(stderr, " context is\n\t");
274 	for (q=ep-1; q>=p && *q!=' ' && *q!='\t' && *q!='\n'; q--)
275 		;
276 	while (p < q)
277 		putc(*p++, stderr);
278 	fprintf(stderr, " >>> ");
279 	while (p < ep)
280 		putc(*p++, stderr);
281 	fprintf(stderr, " <<< ");
282 	while (pb >= pbuf)
283 		putc(*pb--, stderr);
284 	if (curfile->fin)
285 		fgets(ebuf, sizeof ebuf, curfile->fin);
286 	fprintf(stderr, "%s", ebuf);
287 	pbstr("\n.EN\n");	/* safety first */
288 	ep = ebuf;
289 }