1 /*
2 * Copyright (C) 1984-2017 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11 /*
12 * An IFILE represents an input file.
13 *
14 * It is actually a pointer to an ifile structure,
15 * but is opaque outside this module.
16 * Ifile structures are kept in a linked list in the order they
17 * appear on the command line.
18 * Any new file which does not already appear in the list is
19 * inserted after the current file.
20 */
21
22 #include "less.h"
23
24 extern IFILE curr_ifile;
25
26 struct ifile {
27 struct ifile *h_next; /* Links for command line list */
28 struct ifile *h_prev;
29 char *h_filename; /* Name of the file */
30 void *h_filestate; /* File state (used in ch.c) */
31 int h_index; /* Index within command line list */
32 int h_hold; /* Hold count */
33 char h_opened; /* Has this ifile been opened? */
34 struct scrpos h_scrpos; /* Saved position within the file */
35 void *h_altpipe; /* Alt pipe */
36 char *h_altfilename; /* Alt filename */
37 };
38
39 /*
40 * Convert an IFILE (external representation)
41 * to a struct file (internal representation), and vice versa.
42 */
43 #define int_ifile(h) ((struct ifile *)(h))
44 #define ext_ifile(h) ((IFILE)(h))
45
46 /*
47 * Anchor for linked list.
48 */
49 static struct ifile anchor = { &anchor, &anchor, NULL, NULL, 0, 0, '\0',
50 { NULL_POSITION, 0 } };
51 static int ifiles = 0;
52
53 static void
incr_index(p,incr)54 incr_index(p, incr)
55 struct ifile *p;
56 int incr;
57 {
58 for (; p != &anchor; p = p->h_next)
59 p->h_index += incr;
60 }
61
62 /*
63 * Link an ifile into the ifile list.
64 */
65 static void
link_ifile(p,prev)66 link_ifile(p, prev)
67 struct ifile *p;
68 struct ifile *prev;
69 {
70 /*
71 * Link into list.
72 */
73 if (prev == NULL)
74 prev = &anchor;
75 p->h_next = prev->h_next;
76 p->h_prev = prev;
77 prev->h_next->h_prev = p;
78 prev->h_next = p;
79 /*
80 * Calculate index for the new one,
81 * and adjust the indexes for subsequent ifiles in the list.
82 */
83 p->h_index = prev->h_index + 1;
84 incr_index(p->h_next, 1);
85 ifiles++;
86 }
87
88 /*
89 * Unlink an ifile from the ifile list.
90 */
91 static void
unlink_ifile(p)92 unlink_ifile(p)
93 struct ifile *p;
94 {
95 p->h_next->h_prev = p->h_prev;
96 p->h_prev->h_next = p->h_next;
97 incr_index(p->h_next, -1);
98 ifiles--;
99 }
100
101 /*
102 * Allocate a new ifile structure and stick a filename in it.
103 * It should go after "prev" in the list
104 * (or at the beginning of the list if "prev" is NULL).
105 * Return a pointer to the new ifile structure.
106 */
107 static struct ifile *
new_ifile(filename,prev)108 new_ifile(filename, prev)
109 char *filename;
110 struct ifile *prev;
111 {
112 struct ifile *p;
113
114 /*
115 * Allocate and initialize structure.
116 */
117 p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
118 p->h_filename = save(filename);
119 p->h_scrpos.pos = NULL_POSITION;
120 p->h_opened = 0;
121 p->h_hold = 0;
122 p->h_filestate = NULL;
123 link_ifile(p, prev);
124 return (p);
125 }
126
127 /*
128 * Delete an existing ifile structure.
129 */
130 public void
del_ifile(h)131 del_ifile(h)
132 IFILE h;
133 {
134 struct ifile *p;
135
136 if (h == NULL_IFILE)
137 return;
138 /*
139 * If the ifile we're deleting is the currently open ifile,
140 * move off it.
141 */
142 unmark(h);
143 if (h == curr_ifile)
144 curr_ifile = getoff_ifile(curr_ifile);
145 p = int_ifile(h);
146 unlink_ifile(p);
147 free(p->h_filename);
148 free(p);
149 }
150
151 /*
152 * Get the ifile after a given one in the list.
153 */
154 public IFILE
next_ifile(h)155 next_ifile(h)
156 IFILE h;
157 {
158 struct ifile *p;
159
160 p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
161 if (p->h_next == &anchor)
162 return (NULL_IFILE);
163 return (ext_ifile(p->h_next));
164 }
165
166 /*
167 * Get the ifile before a given one in the list.
168 */
169 public IFILE
prev_ifile(h)170 prev_ifile(h)
171 IFILE h;
172 {
173 struct ifile *p;
174
175 p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
176 if (p->h_prev == &anchor)
177 return (NULL_IFILE);
178 return (ext_ifile(p->h_prev));
179 }
180
181 /*
182 * Return a different ifile from the given one.
183 */
184 public IFILE
getoff_ifile(ifile)185 getoff_ifile(ifile)
186 IFILE ifile;
187 {
188 IFILE newifile;
189
190 if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
191 return (newifile);
192 if ((newifile = next_ifile(ifile)) != NULL_IFILE)
193 return (newifile);
194 return (NULL_IFILE);
195 }
196
197 /*
198 * Return the number of ifiles.
199 */
200 public int
nifile()201 nifile()
202 {
203 return (ifiles);
204 }
205
206 /*
207 * Find an ifile structure, given a filename.
208 */
209 static struct ifile *
find_ifile(filename)210 find_ifile(filename)
211 char *filename;
212 {
213 struct ifile *p;
214
215 for (p = anchor.h_next; p != &anchor; p = p->h_next)
216 if (strcmp(filename, p->h_filename) == 0)
217 return (p);
218 return (NULL);
219 }
220
221 /*
222 * Get the ifile associated with a filename.
223 * If the filename has not been seen before,
224 * insert the new ifile after "prev" in the list.
225 */
226 public IFILE
get_ifile(filename,prev)227 get_ifile(filename, prev)
228 char *filename;
229 IFILE prev;
230 {
231 struct ifile *p;
232
233 if ((p = find_ifile(filename)) == NULL)
234 p = new_ifile(filename, int_ifile(prev));
235 return (ext_ifile(p));
236 }
237
238 /*
239 * Get the filename associated with a ifile.
240 */
241 public char *
get_filename(ifile)242 get_filename(ifile)
243 IFILE ifile;
244 {
245 if (ifile == NULL)
246 return (NULL);
247 return (int_ifile(ifile)->h_filename);
248 }
249
250 /*
251 * Get the index of the file associated with a ifile.
252 */
253 public int
get_index(ifile)254 get_index(ifile)
255 IFILE ifile;
256 {
257 return (int_ifile(ifile)->h_index);
258 }
259
260 /*
261 * Save the file position to be associated with a given file.
262 */
263 public void
store_pos(ifile,scrpos)264 store_pos(ifile, scrpos)
265 IFILE ifile;
266 struct scrpos *scrpos;
267 {
268 int_ifile(ifile)->h_scrpos = *scrpos;
269 }
270
271 /*
272 * Recall the file position associated with a file.
273 * If no position has been associated with the file, return NULL_POSITION.
274 */
275 public void
get_pos(ifile,scrpos)276 get_pos(ifile, scrpos)
277 IFILE ifile;
278 struct scrpos *scrpos;
279 {
280 *scrpos = int_ifile(ifile)->h_scrpos;
281 }
282
283 /*
284 * Mark the ifile as "opened".
285 */
286 public void
set_open(ifile)287 set_open(ifile)
288 IFILE ifile;
289 {
290 int_ifile(ifile)->h_opened = 1;
291 }
292
293 /*
294 * Return whether the ifile has been opened previously.
295 */
296 public int
opened(ifile)297 opened(ifile)
298 IFILE ifile;
299 {
300 return (int_ifile(ifile)->h_opened);
301 }
302
303 public void
hold_ifile(ifile,incr)304 hold_ifile(ifile, incr)
305 IFILE ifile;
306 int incr;
307 {
308 int_ifile(ifile)->h_hold += incr;
309 }
310
311 public int
held_ifile(ifile)312 held_ifile(ifile)
313 IFILE ifile;
314 {
315 return (int_ifile(ifile)->h_hold);
316 }
317
318 public void *
get_filestate(ifile)319 get_filestate(ifile)
320 IFILE ifile;
321 {
322 return (int_ifile(ifile)->h_filestate);
323 }
324
325 public void
set_filestate(ifile,filestate)326 set_filestate(ifile, filestate)
327 IFILE ifile;
328 void *filestate;
329 {
330 int_ifile(ifile)->h_filestate = filestate;
331 }
332
333 public void
set_altpipe(ifile,p)334 set_altpipe(ifile, p)
335 IFILE ifile;
336 void *p;
337 {
338 int_ifile(ifile)->h_altpipe = p;
339 }
340
341 public void *
get_altpipe(ifile)342 get_altpipe(ifile)
343 IFILE ifile;
344 {
345 return (int_ifile(ifile)->h_altpipe);
346 }
347
348 public void
set_altfilename(ifile,altfilename)349 set_altfilename(ifile, altfilename)
350 IFILE ifile;
351 char *altfilename;
352 {
353 struct ifile *p = int_ifile(ifile);
354 if (p->h_altfilename != NULL)
355 free(p->h_altfilename);
356 p->h_altfilename = altfilename;
357 }
358
359 public char *
get_altfilename(ifile)360 get_altfilename(ifile)
361 IFILE ifile;
362 {
363 return (int_ifile(ifile)->h_altfilename);
364 }
365
366 #if 0
367 public void
368 if_dump()
369 {
370 struct ifile *p;
371
372 for (p = anchor.h_next; p != &anchor; p = p->h_next)
373 {
374 printf("%x: %d. <%s> pos %d,%x\n",
375 p, p->h_index, p->h_filename,
376 p->h_scrpos.ln, p->h_scrpos.pos);
377 ch_dump(p->h_filestate);
378 }
379 }
380 #endif
381