1 /*
2 * Copyright (C) 1984-2012 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 };
36
37 /*
38 * Convert an IFILE (external representation)
39 * to a struct file (internal representation), and vice versa.
40 */
41 #define int_ifile(h) ((struct ifile *)(h))
42 #define ext_ifile(h) ((IFILE)(h))
43
44 /*
45 * Anchor for linked list.
46 */
47 static struct ifile anchor = { &anchor, &anchor, NULL, NULL, 0, 0, '\0',
48 { NULL_POSITION, 0 } };
49 static int ifiles = 0;
50
51 static void
incr_index(p,incr)52 incr_index(p, incr)
53 register struct ifile *p;
54 int incr;
55 {
56 for (; p != &anchor; p = p->h_next)
57 p->h_index += incr;
58 }
59
60 /*
61 * Link an ifile into the ifile list.
62 */
63 static void
link_ifile(p,prev)64 link_ifile(p, prev)
65 struct ifile *p;
66 struct ifile *prev;
67 {
68 /*
69 * Link into list.
70 */
71 if (prev == NULL)
72 prev = &anchor;
73 p->h_next = prev->h_next;
74 p->h_prev = prev;
75 prev->h_next->h_prev = p;
76 prev->h_next = p;
77 /*
78 * Calculate index for the new one,
79 * and adjust the indexes for subsequent ifiles in the list.
80 */
81 p->h_index = prev->h_index + 1;
82 incr_index(p->h_next, 1);
83 ifiles++;
84 }
85
86 /*
87 * Unlink an ifile from the ifile list.
88 */
89 static void
unlink_ifile(p)90 unlink_ifile(p)
91 struct ifile *p;
92 {
93 p->h_next->h_prev = p->h_prev;
94 p->h_prev->h_next = p->h_next;
95 incr_index(p->h_next, -1);
96 ifiles--;
97 }
98
99 /*
100 * Allocate a new ifile structure and stick a filename in it.
101 * It should go after "prev" in the list
102 * (or at the beginning of the list if "prev" is NULL).
103 * Return a pointer to the new ifile structure.
104 */
105 static struct ifile *
new_ifile(filename,prev)106 new_ifile(filename, prev)
107 char *filename;
108 struct ifile *prev;
109 {
110 register struct ifile *p;
111
112 /*
113 * Allocate and initialize structure.
114 */
115 p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
116 p->h_filename = save(filename);
117 p->h_scrpos.pos = NULL_POSITION;
118 p->h_opened = 0;
119 p->h_hold = 0;
120 p->h_filestate = NULL;
121 link_ifile(p, prev);
122 return (p);
123 }
124
125 /*
126 * Delete an existing ifile structure.
127 */
128 public void
del_ifile(h)129 del_ifile(h)
130 IFILE h;
131 {
132 register struct ifile *p;
133
134 if (h == NULL_IFILE)
135 return;
136 /*
137 * If the ifile we're deleting is the currently open ifile,
138 * move off it.
139 */
140 unmark(h);
141 if (h == curr_ifile)
142 curr_ifile = getoff_ifile(curr_ifile);
143 p = int_ifile(h);
144 unlink_ifile(p);
145 free(p->h_filename);
146 free(p);
147 }
148
149 /*
150 * Get the ifile after a given one in the list.
151 */
152 public IFILE
next_ifile(h)153 next_ifile(h)
154 IFILE h;
155 {
156 register struct ifile *p;
157
158 p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
159 if (p->h_next == &anchor)
160 return (NULL_IFILE);
161 return (ext_ifile(p->h_next));
162 }
163
164 /*
165 * Get the ifile before a given one in the list.
166 */
167 public IFILE
prev_ifile(h)168 prev_ifile(h)
169 IFILE h;
170 {
171 register struct ifile *p;
172
173 p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
174 if (p->h_prev == &anchor)
175 return (NULL_IFILE);
176 return (ext_ifile(p->h_prev));
177 }
178
179 /*
180 * Return a different ifile from the given one.
181 */
182 public IFILE
getoff_ifile(ifile)183 getoff_ifile(ifile)
184 IFILE ifile;
185 {
186 IFILE newifile;
187
188 if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
189 return (newifile);
190 if ((newifile = next_ifile(ifile)) != NULL_IFILE)
191 return (newifile);
192 return (NULL_IFILE);
193 }
194
195 /*
196 * Return the number of ifiles.
197 */
198 public int
nifile()199 nifile()
200 {
201 return (ifiles);
202 }
203
204 /*
205 * Find an ifile structure, given a filename.
206 */
207 static struct ifile *
find_ifile(filename)208 find_ifile(filename)
209 char *filename;
210 {
211 register struct ifile *p;
212
213 for (p = anchor.h_next; p != &anchor; p = p->h_next)
214 if (strcmp(filename, p->h_filename) == 0)
215 return (p);
216 return (NULL);
217 }
218
219 /*
220 * Get the ifile associated with a filename.
221 * If the filename has not been seen before,
222 * insert the new ifile after "prev" in the list.
223 */
224 public IFILE
get_ifile(filename,prev)225 get_ifile(filename, prev)
226 char *filename;
227 IFILE prev;
228 {
229 register struct ifile *p;
230
231 if ((p = find_ifile(filename)) == NULL)
232 p = new_ifile(filename, int_ifile(prev));
233 return (ext_ifile(p));
234 }
235
236 /*
237 * Get the filename associated with a ifile.
238 */
239 public char *
get_filename(ifile)240 get_filename(ifile)
241 IFILE ifile;
242 {
243 if (ifile == NULL)
244 return (NULL);
245 return (int_ifile(ifile)->h_filename);
246 }
247
248 /*
249 * Get the index of the file associated with a ifile.
250 */
251 public int
get_index(ifile)252 get_index(ifile)
253 IFILE ifile;
254 {
255 return (int_ifile(ifile)->h_index);
256 }
257
258 /*
259 * Save the file position to be associated with a given file.
260 */
261 public void
store_pos(ifile,scrpos)262 store_pos(ifile, scrpos)
263 IFILE ifile;
264 struct scrpos *scrpos;
265 {
266 int_ifile(ifile)->h_scrpos = *scrpos;
267 }
268
269 /*
270 * Recall the file position associated with a file.
271 * If no position has been associated with the file, return NULL_POSITION.
272 */
273 public void
get_pos(ifile,scrpos)274 get_pos(ifile, scrpos)
275 IFILE ifile;
276 struct scrpos *scrpos;
277 {
278 *scrpos = int_ifile(ifile)->h_scrpos;
279 }
280
281 /*
282 * Mark the ifile as "opened".
283 */
284 public void
set_open(ifile)285 set_open(ifile)
286 IFILE ifile;
287 {
288 int_ifile(ifile)->h_opened = 1;
289 }
290
291 /*
292 * Return whether the ifile has been opened previously.
293 */
294 public int
opened(ifile)295 opened(ifile)
296 IFILE ifile;
297 {
298 return (int_ifile(ifile)->h_opened);
299 }
300
301 public void
hold_ifile(ifile,incr)302 hold_ifile(ifile, incr)
303 IFILE ifile;
304 int incr;
305 {
306 int_ifile(ifile)->h_hold += incr;
307 }
308
309 public int
held_ifile(ifile)310 held_ifile(ifile)
311 IFILE ifile;
312 {
313 return (int_ifile(ifile)->h_hold);
314 }
315
316 public void *
get_filestate(ifile)317 get_filestate(ifile)
318 IFILE ifile;
319 {
320 return (int_ifile(ifile)->h_filestate);
321 }
322
323 public void
set_filestate(ifile,filestate)324 set_filestate(ifile, filestate)
325 IFILE ifile;
326 void *filestate;
327 {
328 int_ifile(ifile)->h_filestate = filestate;
329 }
330
331 #if 0
332 public void
333 if_dump()
334 {
335 register struct ifile *p;
336
337 for (p = anchor.h_next; p != &anchor; p = p->h_next)
338 {
339 printf("%x: %d. <%s> pos %d,%x\n",
340 p, p->h_index, p->h_filename,
341 p->h_scrpos.ln, p->h_scrpos.pos);
342 ch_dump(p->h_filestate);
343 }
344 }
345 #endif
346