Commit | Line | Data |
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28c97a66 | 1 | static char sccsid[] = "@(#)fio.c 4.2 %G%"; |
c2e9dc00 BJ |
2 | /* |
3 | * sdb - a symbolic debugger for unix - source file access routines. | |
4 | */ | |
5 | #include "head.h" | |
6 | #include <stdio.h> | |
7 | ||
8 | /* | |
9 | * These procedures manage the source files examined by sdb, | |
10 | * providing access to lines by number and utilities for printing | |
11 | * and scrolling. One file is kept open by these routines, and | |
12 | * line index tables are maintained for all files which have been | |
13 | * ``current'' at any time so far. This makes line access trivial, | |
14 | * since the location of each line in the files is known, | |
15 | * although we get ``burned'' if the file is changed. | |
16 | * SHOULD WATCH THE MODTIME OF FILES AND REINDEX IF IT CHANGES. | |
17 | */ | |
18 | ||
19 | /* | |
20 | * Structure for files which have been ``indexed''. | |
21 | * Contains a pointer to the file name, a pointer to an | |
22 | * array of seek pointers for the lines in the file, | |
23 | * and a next link in a chain of these for all files we have indexed, | |
24 | * The currently open file is cinfo->; the chain of active files is finfo. | |
25 | */ | |
26 | struct finfo { | |
27 | char *name; /* name of this file w/o common pfx */ | |
28 | off_t *lines; /* array of seek pointers */ | |
29 | /* line i stretches from lines[i-1] to lines[i] - 1, if first line is 1 */ | |
30 | int nlines; /* number of lines in file */ | |
31 | /* lines array actually has nlines+1 elements, so last line is bracketed */ | |
32 | struct finfo *next; /* link in chain of known files */ | |
33 | } *finfo, *cfile; | |
34 | FILE *FIO; /* current open file (only 1 now) */ | |
35 | char fibuf[BUFSIZ]; | |
36 | /* | |
37 | * We use stdio when first reading the file, but thereafter | |
38 | * use our own routines, because we want to be able | |
39 | * to read backwards efficiently and avoid a tell() system | |
40 | * call on each line. Fseekpt remebers where we are in the current | |
41 | * file. | |
42 | */ | |
43 | off_t fseekpt; | |
44 | ||
45 | /* | |
46 | * Make ``name'' the current source file, if it isn't already. | |
47 | * If we have never seen this file before, then we create a finfo | |
48 | * structure for it indexing the lines (this requires reading the | |
49 | * entire file and building an index, but is well worth it since | |
50 | * we otherwise have to brute force search the files all the time.) | |
51 | */ | |
52 | finit(name) | |
53 | char *name; | |
54 | { | |
55 | char buf[BUFSIZ]; | |
56 | register off_t *lp; | |
57 | ||
58 | if (cfile && !strcmp(cfile->name, name)) | |
59 | return; /* its already current, do nothing */ | |
60 | /* IT WOULD BE BETTER TO HAVE A COUPLE OF FILE DESCRIPTORS, LRU */ | |
61 | if (FIO) { | |
62 | fclose(FIO); | |
63 | FIO = NULL; | |
64 | } | |
65 | /* | |
66 | * Paste the given name onto the common prefix (directory path) | |
67 | * to form the full name of the file to be opened. | |
68 | */ | |
69 | strcpy(fp, name); | |
70 | if ((FIO = fopen(filework, "r")) == NULL) { | |
71 | nolines = 1; | |
72 | perror(filework); | |
73 | return; | |
74 | } | |
75 | setbuf(FIO, fibuf); | |
76 | fseekpt = -BUFSIZ; /* putatively illegal */ | |
77 | strcpy(curfile, name); | |
78 | /* | |
79 | * See if we have alread indexed this file. | |
80 | * If so, nothing much to do. | |
81 | */ | |
82 | for (cfile = finfo; cfile; cfile = cfile->next) | |
83 | if (!strcmp(cfile->name, name)) | |
84 | return; | |
85 | /* | |
86 | * Create a structure for this (new) file. | |
87 | * Lines array grows 100 lines at a time. | |
88 | * 1 extra so last line is bracketed. | |
89 | */ | |
90 | cfile = (struct finfo *)sbrk(sizeof (struct finfo)); | |
91 | lp = cfile->lines = (off_t *)sbrk(101 * sizeof (off_t)); | |
92 | *lp++ = 0; /* line 1 starts at 0 ... */ | |
93 | cfile->nlines = 0; | |
94 | /* IT WOULD PROBABLY BE FASTER TO JUST USE GETC AND LOOK FOR \n */ | |
95 | while (fgets(buf, sizeof buf, FIO)) { | |
96 | if ((++cfile->nlines % 100) == 0) | |
97 | sbrk(100 * sizeof (off_t)); | |
98 | /* | |
99 | * Mark end of the cfile->nlines'th line | |
100 | */ | |
101 | lp[0] = lp[-1] + strlen(buf); | |
102 | lp++; | |
103 | } | |
104 | if (cfile->nlines == 0) { | |
105 | printf("%s: no lines in file\n", filework); | |
106 | cfile = 0; | |
107 | return; | |
108 | } | |
109 | /* | |
110 | * Allocate space for the name, making sure to leave the | |
111 | * break on a word boundary. | |
112 | * IT WOULD BE MUCH BETTER TO USE MALLOC AND REALLOC IN SDB. | |
113 | */ | |
114 | sbrk(lp + ((strlen(name)+sizeof(off_t)-1)&~(sizeof(off_t)-1))); | |
115 | strcpy(cfile->name = (char *)lp, name); | |
116 | cfile->next = finfo; | |
117 | finfo = cfile; | |
118 | } | |
119 | ||
120 | /* | |
121 | * Get the current line (fline) into fbuf | |
122 | */ | |
123 | fgetline() | |
124 | { | |
125 | register off_t *op = &cfile->lines[fline-1]; | |
126 | int o, n; | |
127 | ||
128 | n = op[1] - op[0]; | |
129 | fbuf[n] = 0; | |
130 | /* | |
131 | * Case 1. Line begins in current buffer. | |
132 | * | |
133 | * Compute the number of characters into the buffer where | |
134 | * the line starts. If this offset plus its length is greater | |
135 | * than BUFSIZ, then this line splits across a buffer boundary | |
136 | * so take the rest of this buffer and the first part of the next. | |
137 | * Otherwise just take a chunk of this buffer. | |
138 | */ | |
139 | if (*op >= fseekpt && *op < fseekpt + BUFSIZ) { | |
140 | case1: | |
141 | o = op[0] - fseekpt; | |
142 | if (o + n > BUFSIZ) { | |
143 | strncpy(fbuf, fibuf+o, BUFSIZ-o); | |
144 | fseekpt += BUFSIZ; | |
145 | read(fileno(FIO), fibuf, BUFSIZ); | |
146 | strncpy(fbuf+BUFSIZ-o, fibuf, n-(BUFSIZ-o)); | |
147 | } else | |
148 | strncpy(fbuf, fibuf+o, n); | |
149 | return; | |
150 | } | |
151 | /* | |
152 | * Case 2. Line ends in current buffer. | |
153 | * | |
154 | * If the line ends in this buffer (but doesn't begin in | |
155 | * it or else we would have had case 1) take the beginning | |
156 | * part of the buffer (end of the line) and then back up and | |
157 | * get the rest of the line from the end of the previous block. | |
158 | */ | |
159 | if (op[1]-1 >= fseekpt && op[1] <= fseekpt+BUFSIZ) { | |
160 | o = op[1] - fseekpt; | |
161 | strncpy(fbuf+n-o, fibuf, o); | |
162 | fseekpt -= BUFSIZ; | |
163 | lseek(fileno(FIO), fseekpt, 0); | |
164 | read(fileno(FIO), fibuf, BUFSIZ); | |
165 | strncpy(fbuf, fibuf+op[0]-fseekpt, n-o); | |
166 | return; | |
167 | } | |
168 | /* | |
169 | * Case 3. Line not in current buffer at all. | |
170 | * | |
171 | * Read in the buffer where the line starts and then go | |
172 | * back and handle as case 1. | |
173 | */ | |
174 | fseekpt = (op[0] / BUFSIZ) * BUFSIZ; | |
175 | lseek(fileno(FIO), fseekpt, 0); | |
176 | read(fileno(FIO), fibuf, BUFSIZ); | |
177 | goto case1; | |
178 | } | |
179 | ||
180 | /* | |
181 | * Advance current line, end-around (like for / search). | |
182 | */ | |
183 | fnext() | |
184 | { | |
185 | ||
186 | if (cfile == 0) | |
187 | return; | |
188 | if (fline == cfile->nlines) { | |
189 | fline = 1; | |
190 | } else | |
191 | fline++; | |
192 | fgetline(); | |
193 | } | |
194 | ||
195 | /* | |
196 | * Retreat the current line, end around. | |
197 | */ | |
198 | fprev() | |
199 | { | |
200 | ||
201 | if (cfile == 0) | |
202 | return; | |
203 | if (fline == 1) | |
204 | fline = cfile->nlines; | |
205 | else | |
206 | fline--; | |
207 | fgetline(); | |
208 | } | |
209 | ||
210 | /* | |
211 | * Print the current line. | |
212 | */ | |
213 | fprint() | |
214 | { | |
215 | register char *p; | |
216 | ||
217 | if (cfile == 0) { | |
218 | error("No lines in file"); | |
219 | return; | |
220 | } | |
221 | printf("%d: %s", fline, fbuf); | |
222 | } | |
223 | ||
224 | /* | |
225 | * Make line `num' current. | |
226 | */ | |
227 | ffind(num) | |
228 | register int num; | |
229 | { | |
230 | ||
231 | if (cfile == 0) | |
232 | return; | |
233 | if (num > cfile->nlines) | |
234 | error("Not that many lines in file"); | |
235 | else if (num <= 0) | |
236 | error("Zero or negative line?"); | |
237 | else { | |
238 | fline = num; | |
239 | fgetline(); | |
240 | } | |
241 | } | |
242 | ||
243 | /* | |
244 | * Go back n lines. | |
245 | */ | |
246 | fback(n) | |
247 | { | |
248 | int i; | |
249 | ||
250 | if (cfile == 0) | |
251 | return (0); | |
252 | if (n > fline - 1) | |
253 | n = fline - 1; | |
254 | fline -= n; | |
255 | fgetline(); | |
256 | return (n); | |
257 | } | |
258 | ||
259 | /* | |
260 | * Go forwards n lines. | |
261 | */ | |
262 | fforward(n) | |
263 | int n; | |
264 | { | |
265 | register int fnext; | |
266 | ||
267 | if (cfile == 0) | |
268 | return(0); | |
269 | if (fline + n > cfile->nlines) | |
270 | n = cfile->nlines - fline; | |
271 | fline += n; | |
272 | fgetline(); | |
273 | return (n); | |
274 | } | |
275 | ||
276 | /* | |
277 | * Print (upto) n lines, returning number printed. | |
278 | */ | |
279 | fprintn(n) | |
280 | int n; | |
281 | { | |
282 | register int i; | |
283 | ||
284 | if (cfile == 0) { | |
285 | error("No lines in file"); | |
286 | return (0); | |
287 | } | |
288 | for (i = 1; i <= n; i++) { | |
289 | fprint(); | |
290 | if (fline == cfile->nlines || i == n) | |
291 | return(i); | |
292 | fnext(); | |
293 | } | |
294 | return (n); | |
295 | } |