1 #include "e.h"
2 #include "y.tab.h"
3 #include <ctype.h>
4 #include <errno.h>
5 
6 Infile	infile[10];
7 Infile	*curfile = infile;
8 
9 #define	MAXSRC	50
10 Src	src[MAXSRC];	/* input source stack */
11 Src	*srcp	= src;
12 
13 extern int getarg(char *);
14 extern	void eprint(void);
15 
16 void pushsrc(int type, char *ptr)	/* new input source */
17 {
18 	if (++srcp >= src + MAXSRC)
19 		ERROR "inputs nested too deep" FATAL;
20 	srcp->type = type;
21 	srcp->sp = ptr;
22 	if (dbg > 1) {
23 		printf("\n%3d ", srcp - src);
24 		switch (srcp->type) {
25 		case File:
26 			printf("push file %s\n", ((Infile *)ptr)->fname);
27 			break;
28 		case Macro:
29 			printf("push macro <%s>\n", ptr);
30 			break;
31 		case Char:
32 			printf("push char <%c>\n", *ptr);
33 			break;
34 		case String:
35 			printf("push string <%s>\n", ptr);
36 			break;
37 		case Free:
38 			printf("push free <%s>\n", ptr);
39 			break;
40 		default:
41 			ERROR "pushed bad type %d\n", srcp->type FATAL;
42 		}
43 	}
44 }
45 
46 void popsrc(void)	/* restore an old one */
47 {
48 	if (srcp <= src)
49 		ERROR "too many inputs popped" FATAL;
50 	if (dbg > 1) {
51 		printf("%3d ", srcp - src);
52 		switch (srcp->type) {
53 		case File:
54 			printf("pop file\n");
55 			break;
56 		case Macro:
57 			printf("pop macro\n");
58 			break;
59 		case Char:
60 			printf("pop char <%c>\n", *srcp->sp);
61 			break;
62 		case String:
63 			printf("pop string\n");
64 			break;
65 		case Free:
66 			printf("pop free\n");
67 			break;
68 		default:
69 			ERROR "pop weird input %d\n", srcp->type FATAL;
70 		}
71 	}
72 	srcp--;
73 }
74 
75 Arg	args[10];	/* argument frames */
76 Arg	*argfp = args;	/* frame pointer */
77 int	argcnt;		/* number of arguments seen so far */
78 
79 void dodef(tbl *stp)	/* collect args and switch input to defn */
80 {
81 	int i, len;
82 	char *p;
83 	Arg *ap;
84 
85 	ap = argfp+1;
86 	if (ap >= args+10)
87 		ERROR "more than arguments\n" FATAL;
88 	argcnt = 0;
89 	if (input() != '(')
90 		ERROR "disaster in dodef\n"FATAL;
91 	if (ap->argval == 0)
92 		ap->argval = malloc(1000);
93 	for (p = ap->argval; (len = getarg(p)) != -1; p += len) {
94 		ap->argstk[argcnt++] = p;
95 		if (input() == ')')
96 			break;
97 	}
98 	for (i = argcnt; i < MAXARGS; i++)
99 		ap->argstk[i] = "";
100 	if (dbg)
101 		for (i = 0; i < argcnt; i++)
102 			printf("arg %d.%d = <%s>\n", ap-args, i+1, ap->argstk[i]);
103 	argfp = ap;
104 	pushsrc(Macro, stp->cval);
105 }
106 
107 int
108 getarg(char *p)	/* pick up single argument, store in p, return length */
109 {
110 	int n, c, npar;
111 
112 	n = npar = 0;
113 	for ( ;; ) {
114 		c = input();
115 		if (c == EOF)
116 			ERROR "end of file in getarg!\n" FATAL;
117 		if (npar == 0 && (c == ',' || c == ')'))
118 			break;
119 		if (c == '"')	/* copy quoted stuff intact */
120 			do {
121 				*p++ = c;
122 				n++;
123 			} while ((c = input()) != '"' && c != EOF);
124 		else if (c == '(')
125 			npar++;
126 		else if (c == ')')
127 			npar--;
128 		n++;
129 		*p++ = c;
130 	}
131 	*p = 0;
132 	unput(c);
133 	return(n + 1);
134 }
135 
136 #define	PBSIZE	2000
137 char	pbuf[PBSIZE];		/* pushback buffer */
138 char	*pb	= pbuf-1;	/* next pushed back character */
139 
140 char	ebuf[200];		/* collect input here for error reporting */
141 char	*ep	= ebuf;
142 
143 int
144 input(void)
145 {
146 	register int c = 0;
147 
148   loop:
149 	switch (srcp->type) {
150 	case File:
151 		c = getc(curfile->fin);
152 		if (c == EOF) {
153 			if (curfile == infile)
154 				break;
155 			if (curfile->fin != stdin) {
156 				fclose(curfile->fin);
157 				free(curfile->fname);	/* assumes allocated */
158 			}
159 			curfile--;
160 			printf(".lf %d %s\n", curfile->lineno, curfile->fname);
161 			popsrc();
162 			goto loop;
163 		}
164 		if (c == '\n')
165 			curfile->lineno++;
166 		break;
167 	case Char:
168 		if (pb >= pbuf) {
169 			c = *pb--;
170 			popsrc();
171 			break;
172 		} else {	/* can't happen? */
173 			popsrc();
174 			goto loop;
175 		}
176 	case String:
177 		c = *srcp->sp++;
178 		if (c == '\0') {
179 			popsrc();
180 			goto loop;
181 		} else {
182 			if (*srcp->sp == '\0')	/* empty, so pop */
183 				popsrc();
184 			break;
185 		}
186 	case Macro:
187 		c = *srcp->sp++;
188 		if (c == '\0') {
189 			if (--argfp < args)
190 				ERROR "argfp underflow" FATAL;
191 			popsrc();
192 			goto loop;
193 		} else if (c == '$' && isdigit(*srcp->sp)) {
194 			int n = 0;
195 			while (isdigit(*srcp->sp))
196 				n = 10 * n + *srcp->sp++ - '0';
197 			if (n > 0 && n <= MAXARGS)
198 				pushsrc(String, argfp->argstk[n-1]);
199 			goto loop;
200 		}
201 		break;
202 	case Free:	/* free string */
203 		free(srcp->sp);
204 		popsrc();
205 		goto loop;
206 	}
207 	if (ep >= ebuf + sizeof ebuf)
208 		ep = ebuf;
209 	*ep++ = c;
210 	return c;
211 }
212 
213 int
214 unput(int c)
215 {
216 	if (++pb >= pbuf + sizeof pbuf)
217 		ERROR "pushback overflow\n"FATAL;
218 	if (--ep < ebuf)
219 		ep = ebuf + sizeof(ebuf) - 1;
220 	*pb = c;
221 	pushsrc(Char, pb);
222 	return c;
223 }
224 
225 void pbstr(char *s)
226 {
227 	pushsrc(String, s);
228 }
229 
230 void error(int die, char *s)
231 {
232 	extern char *cmdname;
233 
234 	if (synerr)
235 		return;
236 	fprintf(stderr, "%s: ", cmdname);
237 	fprintf(stderr, s);
238 	if (errno > 0)
239 		perror("???");
240 	if (curfile->fin)
241 		fprintf(stderr, " near %s:%d",
242 			curfile->fname, curfile->lineno+1);
243 	fprintf(stderr, "\n");
244 	eprint();
245 	synerr = 1;
246 	errno = 0;
247 	if (die) {
248 		if (dbg)
249 			abort();
250 		else
251 			exit(1);
252 	}
253 }
254 
255 void yyerror(char *s)
256 {
257 	error(0, s);	/* temporary */
258 }
259 
260 char errbuf[200];
261 
262 void eprint(void)	/* try to print context around error */
263 {
264 	char *p, *q;
265 
266 	if (ep == ebuf)
267 		return;				/* no context */
268 	p = ep - 1;
269 	if (p > ebuf && *p == '\n')
270 		p--;
271 	for ( ; p >= ebuf && *p != '\n'; p--)
272 		;
273 	while (*p == '\n')
274 		p++;
275 	fprintf(stderr, " context is\n\t");
276 	for (q=ep-1; q>=p && *q!=' ' && *q!='\t' && *q!='\n'; q--)
277 		;
278 	while (p < q)
279 		putc(*p++, stderr);
280 	fprintf(stderr, " >>> ");
281 	while (p < ep)
282 		putc(*p++, stderr);
283 	fprintf(stderr, " <<< ");
284 	while (pb >= pbuf)
285 		putc(*pb--, stderr);
286 	if (curfile->fin)
287 		fgets(ebuf, sizeof ebuf, curfile->fin);
288 	fprintf(stderr, "%s", ebuf);
289 	pbstr("\n.EN\n");	/* safety first */
290 	ep = ebuf;
291 }