Annotation of src/usr.bin/less/ifile.c, Revision 1.4
1.1 etheisen 1: /*
1.4 ! millert 2: * Copyright (C) 1984-2002 Mark Nudelman
1.1 etheisen 3: *
1.4 ! millert 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.
1.1 etheisen 6: *
1.4 ! millert 7: * For more information about less, or for information on how to
! 8: * contact the author, see the README file.
1.1 etheisen 9: */
10:
11:
12: /*
13: * An IFILE represents an input file.
14: *
15: * It is actually a pointer to an ifile structure,
16: * but is opaque outside this module.
17: * Ifile structures are kept in a linked list in the order they
18: * appear on the command line.
19: * Any new file which does not already appear in the list is
20: * inserted after the current file.
21: */
22:
23: #include "less.h"
24:
25: extern IFILE curr_ifile;
26:
27: struct ifile {
28: struct ifile *h_next; /* Links for command line list */
29: struct ifile *h_prev;
30: char *h_filename; /* Name of the file */
31: void *h_filestate; /* File state (used in ch.c) */
32: int h_index; /* Index within command line list */
1.4 ! millert 33: int h_hold; /* Hold count */
! 34: char h_opened; /* Has this ifile been opened? */
1.1 etheisen 35: struct scrpos h_scrpos; /* Saved position within the file */
36: };
37:
38: /*
39: * Convert an IFILE (external representation)
40: * to a struct file (internal representation), and vice versa.
41: */
42: #define int_ifile(h) ((struct ifile *)(h))
43: #define ext_ifile(h) ((IFILE)(h))
44:
45: /*
46: * Anchor for linked list.
47: */
1.4 ! millert 48: static struct ifile anchor = { &anchor, &anchor, NULL, NULL, 0, 0, '\0',
! 49: { NULL_POSITION, 0 } };
1.1 etheisen 50: static int ifiles = 0;
51:
52: static void
53: incr_index(p, incr)
1.4 ! millert 54: register struct ifile *p;
1.1 etheisen 55: int incr;
56: {
57: for (; p != &anchor; p = p->h_next)
58: p->h_index += incr;
59: }
60:
1.4 ! millert 61: /*
! 62: * Link an ifile into the ifile list.
! 63: */
1.1 etheisen 64: static void
65: link_ifile(p, prev)
66: struct ifile *p;
67: struct ifile *prev;
68: {
69: /*
70: * Link into list.
71: */
72: if (prev == NULL)
73: prev = &anchor;
74: p->h_next = prev->h_next;
75: p->h_prev = prev;
76: prev->h_next->h_prev = p;
77: prev->h_next = p;
78: /*
79: * Calculate index for the new one,
80: * and adjust the indexes for subsequent ifiles in the list.
81: */
82: p->h_index = prev->h_index + 1;
83: incr_index(p->h_next, 1);
84: ifiles++;
85: }
86:
1.4 ! millert 87: /*
! 88: * Unlink an ifile from the ifile list.
! 89: */
1.1 etheisen 90: static void
91: unlink_ifile(p)
92: struct ifile *p;
93: {
94: p->h_next->h_prev = p->h_prev;
95: p->h_prev->h_next = p->h_next;
96: incr_index(p->h_next, -1);
97: ifiles--;
98: }
99:
100: /*
101: * Allocate a new ifile structure and stick a filename in it.
102: * It should go after "prev" in the list
103: * (or at the beginning of the list if "prev" is NULL).
104: * Return a pointer to the new ifile structure.
105: */
106: static struct ifile *
107: new_ifile(filename, prev)
108: char *filename;
109: struct ifile *prev;
110: {
1.4 ! millert 111: register struct ifile *p;
1.1 etheisen 112:
113: /*
114: * Allocate and initialize structure.
115: */
116: p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
117: p->h_filename = save(filename);
118: p->h_scrpos.pos = NULL_POSITION;
119: p->h_opened = 0;
1.4 ! millert 120: p->h_hold = 0;
! 121: p->h_filestate = NULL;
1.1 etheisen 122: link_ifile(p, prev);
123: return (p);
124: }
125:
126: /*
127: * Delete an existing ifile structure.
128: */
129: public void
130: del_ifile(h)
131: IFILE h;
132: {
1.4 ! millert 133: register struct ifile *p;
1.1 etheisen 134:
135: if (h == NULL_IFILE)
136: return;
137: /*
138: * If the ifile we're deleting is the currently open ifile,
139: * move off it.
140: */
1.4 ! millert 141: unmark(h);
1.1 etheisen 142: if (h == curr_ifile)
143: curr_ifile = getoff_ifile(curr_ifile);
144: p = int_ifile(h);
145: unlink_ifile(p);
146: free(p->h_filename);
147: free(p);
148: }
149:
150: /*
151: * Get the ifile after a given one in the list.
152: */
153: public IFILE
154: next_ifile(h)
155: IFILE h;
156: {
1.4 ! millert 157: register struct ifile *p;
1.1 etheisen 158:
159: p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
160: if (p->h_next == &anchor)
161: return (NULL_IFILE);
162: return (ext_ifile(p->h_next));
163: }
164:
165: /*
166: * Get the ifile before a given one in the list.
167: */
168: public IFILE
169: prev_ifile(h)
170: IFILE h;
171: {
1.4 ! millert 172: register struct ifile *p;
1.1 etheisen 173:
174: p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
175: if (p->h_prev == &anchor)
176: return (NULL_IFILE);
177: return (ext_ifile(p->h_prev));
178: }
179:
180: /*
181: * Return a different ifile from the given one.
182: */
183: public IFILE
184: getoff_ifile(ifile)
185: IFILE ifile;
186: {
187: IFILE newifile;
188:
189: if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
190: return (newifile);
191: if ((newifile = next_ifile(ifile)) != NULL_IFILE)
192: return (newifile);
193: return (NULL_IFILE);
194: }
195:
196: /*
197: * Return the number of ifiles.
198: */
199: public int
200: nifile()
201: {
202: return (ifiles);
203: }
204:
205: /*
206: * Find an ifile structure, given a filename.
207: */
208: static struct ifile *
209: find_ifile(filename)
210: char *filename;
211: {
1.4 ! millert 212: register struct ifile *p;
1.1 etheisen 213:
214: for (p = anchor.h_next; p != &anchor; p = p->h_next)
215: if (strcmp(filename, p->h_filename) == 0)
216: return (p);
217: return (NULL);
218: }
219:
220: /*
221: * Get the ifile associated with a filename.
222: * If the filename has not been seen before,
223: * insert the new ifile after "prev" in the list.
224: */
225: public IFILE
226: get_ifile(filename, prev)
227: char *filename;
228: IFILE prev;
229: {
1.4 ! millert 230: register struct ifile *p;
1.1 etheisen 231:
232: if ((p = find_ifile(filename)) == NULL)
233: p = new_ifile(filename, int_ifile(prev));
234: return (ext_ifile(p));
235: }
236:
237: /*
238: * Get the filename associated with a ifile.
239: */
240: public char *
241: get_filename(ifile)
242: IFILE ifile;
243: {
244: if (ifile == NULL)
245: return (NULL);
246: return (int_ifile(ifile)->h_filename);
247: }
248:
249: /*
250: * Get the index of the file associated with a ifile.
251: */
252: public int
253: get_index(ifile)
254: IFILE ifile;
255: {
256: return (int_ifile(ifile)->h_index);
257: }
258:
259: /*
260: * Save the file position to be associated with a given file.
261: */
262: public void
263: store_pos(ifile, scrpos)
264: IFILE ifile;
265: struct scrpos *scrpos;
266: {
267: int_ifile(ifile)->h_scrpos = *scrpos;
268: }
269:
270: /*
271: * Recall the file position associated with a file.
272: * If no position has been associated with the file, return NULL_POSITION.
273: */
274: public void
275: get_pos(ifile, scrpos)
276: IFILE ifile;
277: struct scrpos *scrpos;
278: {
279: *scrpos = int_ifile(ifile)->h_scrpos;
280: }
281:
282: /*
283: * Mark the ifile as "opened".
284: */
285: public void
286: set_open(ifile)
287: IFILE ifile;
288: {
289: int_ifile(ifile)->h_opened = 1;
290: }
291:
292: /*
293: * Return whether the ifile has been opened previously.
294: */
295: public int
296: opened(ifile)
297: IFILE ifile;
298: {
299: return (int_ifile(ifile)->h_opened);
300: }
301:
1.4 ! millert 302: public void
! 303: hold_ifile(ifile, incr)
! 304: IFILE ifile;
! 305: int incr;
! 306: {
! 307: int_ifile(ifile)->h_hold += incr;
! 308: }
! 309:
! 310: public int
! 311: held_ifile(ifile)
! 312: IFILE ifile;
! 313: {
! 314: return (int_ifile(ifile)->h_hold);
! 315: }
! 316:
1.1 etheisen 317: public void *
318: get_filestate(ifile)
319: IFILE ifile;
320: {
321: return (int_ifile(ifile)->h_filestate);
322: }
323:
324: public void
325: set_filestate(ifile, filestate)
326: IFILE ifile;
327: void *filestate;
328: {
329: int_ifile(ifile)->h_filestate = filestate;
330: }
331:
332: #if 0
333: public void
334: if_dump()
335: {
1.4 ! millert 336: register struct ifile *p;
1.1 etheisen 337:
338: for (p = anchor.h_next; p != &anchor; p = p->h_next)
339: {
340: printf("%x: %d. <%s> pos %d,%x\n",
341: p, p->h_index, p->h_filename,
342: p->h_scrpos.ln, p->h_scrpos.pos);
343: ch_dump(p->h_filestate);
344: }
345: }
346: #endif
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