Annotation of src/usr.bin/less/input.c, Revision 1.9
1.1 etheisen 1: /*
1.7 shadchin 2: * Copyright (C) 1984-2012 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: *
1.7 shadchin 7: * For more information, see the README file.
1.1 etheisen 8: */
1.8 nicm 9: /*
10: * Modified for use with illumos.
11: * Copyright 2014 Garrett D'Amore <garrett@damore.org>
12: */
1.1 etheisen 13:
14: /*
1.8 nicm 15: * High level routines dealing with getting lines of input
1.1 etheisen 16: * from the file being viewed.
17: *
18: * When we speak of "lines" here, we mean PRINTABLE lines;
19: * lines processed with respect to the screen width.
20: * We use the term "raw line" to refer to lines simply
21: * delimited by newlines; not processed with respect to screen width.
22: */
23:
24: #include "less.h"
25:
26: extern int squeeze;
27: extern int chopline;
1.4 millert 28: extern int hshift;
29: extern int quit_if_one_screen;
1.6 millert 30: extern volatile sig_atomic_t sigs;
1.4 millert 31: extern int ignore_eoi;
1.5 shadchin 32: extern int status_col;
1.8 nicm 33: extern off_t start_attnpos;
34: extern off_t end_attnpos;
1.1 etheisen 35: extern int hilite_search;
36: extern int size_linebuf;
37:
38: /*
39: * Get the next line.
40: * A "current" position is passed and a "new" position is returned.
41: * The current position is the position of the first character of
42: * a line. The new position is the position of the first character
43: * of the NEXT line. The line obtained is the line starting at curr_pos.
44: */
1.8 nicm 45: off_t
46: forw_line(off_t curr_pos)
1.1 etheisen 47: {
1.8 nicm 48: off_t base_pos;
49: off_t new_pos;
1.9 ! tedu 50: int c;
1.1 etheisen 51: int blankline;
52: int endline;
1.5 shadchin 53: int backchars;
1.1 etheisen 54:
1.5 shadchin 55: get_forw_line:
1.8 nicm 56: if (curr_pos == -1) {
1.1 etheisen 57: null_line();
1.8 nicm 58: return (-1);
1.1 etheisen 59: }
1.5 shadchin 60: if (hilite_search == OPT_ONPLUS || is_filtering() || status_col)
1.4 millert 61: /*
62: * If we are ignoring EOI (command F), only prepare
63: * one line ahead, to avoid getting stuck waiting for
64: * slow data without displaying the data we already have.
65: * If we're not ignoring EOI, we *could* do the same, but
66: * for efficiency we prepare several lines ahead at once.
67: */
1.8 nicm 68: prep_hilite(curr_pos, curr_pos + 3*size_linebuf,
69: ignore_eoi ? 1 : -1);
70: if (ch_seek(curr_pos)) {
1.1 etheisen 71: null_line();
1.8 nicm 72: return (-1);
1.1 etheisen 73: }
74:
1.5 shadchin 75: /*
76: * Step back to the beginning of the line.
77: */
78: base_pos = curr_pos;
1.8 nicm 79: for (;;) {
80: if (ABORT_SIGS()) {
1.5 shadchin 81: null_line();
1.8 nicm 82: return (-1);
1.5 shadchin 83: }
84: c = ch_back_get();
85: if (c == EOI)
86: break;
1.8 nicm 87: if (c == '\n') {
1.5 shadchin 88: (void) ch_forw_get();
89: break;
90: }
91: --base_pos;
92: }
93:
94: /*
95: * Read forward again to the position we should start at.
96: */
1.8 nicm 97: prewind();
1.5 shadchin 98: plinenum(base_pos);
99: (void) ch_seek(base_pos);
100: new_pos = base_pos;
1.8 nicm 101: while (new_pos < curr_pos) {
102: if (ABORT_SIGS()) {
1.5 shadchin 103: null_line();
1.8 nicm 104: return (-1);
1.5 shadchin 105: }
106: c = ch_forw_get();
107: backchars = pappend(c, new_pos);
108: new_pos++;
1.8 nicm 109: if (backchars > 0) {
1.5 shadchin 110: pshift_all();
111: new_pos -= backchars;
112: while (--backchars >= 0)
113: (void) ch_back_get();
114: }
115: }
116: (void) pflushmbc();
117: pshift_all();
1.1 etheisen 118:
1.5 shadchin 119: /*
120: * Read the first character to display.
121: */
1.1 etheisen 122: c = ch_forw_get();
1.8 nicm 123: if (c == EOI) {
1.1 etheisen 124: null_line();
1.8 nicm 125: return (-1);
1.1 etheisen 126: }
127: blankline = (c == '\n' || c == '\r');
128:
1.5 shadchin 129: /*
130: * Read each character in the line and append to the line buffer.
131: */
1.8 nicm 132: for (;;) {
133: if (ABORT_SIGS()) {
1.1 etheisen 134: null_line();
1.8 nicm 135: return (-1);
1.1 etheisen 136: }
1.8 nicm 137: if (c == '\n' || c == EOI) {
1.1 etheisen 138: /*
139: * End of the line.
140: */
1.5 shadchin 141: backchars = pflushmbc();
1.1 etheisen 142: new_pos = ch_tell();
1.8 nicm 143: if (backchars > 0 && !chopline && hshift == 0) {
1.5 shadchin 144: new_pos -= backchars + 1;
145: endline = FALSE;
146: } else
147: endline = TRUE;
1.1 etheisen 148: break;
149: }
1.5 shadchin 150: if (c != '\r')
151: blankline = 0;
1.1 etheisen 152:
153: /*
154: * Append the char to the line and get the next char.
155: */
1.5 shadchin 156: backchars = pappend(c, ch_tell()-1);
1.8 nicm 157: if (backchars > 0) {
1.1 etheisen 158: /*
159: * The char won't fit in the line; the line
160: * is too long to print in the screen width.
161: * End the line here.
162: */
1.8 nicm 163: if (chopline || hshift > 0) {
164: do {
165: if (ABORT_SIGS()) {
1.5 shadchin 166: null_line();
1.8 nicm 167: return (-1);
1.5 shadchin 168: }
1.1 etheisen 169: c = ch_forw_get();
170: } while (c != '\n' && c != EOI);
171: new_pos = ch_tell();
1.4 millert 172: endline = TRUE;
173: quit_if_one_screen = FALSE;
1.8 nicm 174: } else {
1.5 shadchin 175: new_pos = ch_tell() - backchars;
1.4 millert 176: endline = FALSE;
1.1 etheisen 177: }
178: break;
179: }
180: c = ch_forw_get();
181: }
1.5 shadchin 182:
183: pdone(endline, 1);
184:
1.8 nicm 185: if (is_filtered(base_pos)) {
1.5 shadchin 186: /*
187: * We don't want to display this line.
188: * Get the next line.
189: */
190: curr_pos = new_pos;
191: goto get_forw_line;
192: }
193:
194: if (status_col && is_hilited(base_pos, ch_tell()-1, 1, NULL))
195: set_status_col('*');
1.1 etheisen 196:
1.8 nicm 197: if (squeeze && blankline) {
1.1 etheisen 198: /*
199: * This line is blank.
200: * Skip down to the last contiguous blank line
201: * and pretend it is the one which we are returning.
202: */
203: while ((c = ch_forw_get()) == '\n' || c == '\r')
1.8 nicm 204: if (ABORT_SIGS()) {
1.1 etheisen 205: null_line();
1.8 nicm 206: return (-1);
1.1 etheisen 207: }
208: if (c != EOI)
209: (void) ch_back_get();
210: new_pos = ch_tell();
211: }
212:
213: return (new_pos);
214: }
215:
216: /*
217: * Get the previous line.
218: * A "current" position is passed and a "new" position is returned.
219: * The current position is the position of the first character of
220: * a line. The new position is the position of the first character
221: * of the PREVIOUS line. The line obtained is the one starting at new_pos.
222: */
1.8 nicm 223: off_t
224: back_line(off_t curr_pos)
1.1 etheisen 225: {
1.8 nicm 226: off_t new_pos, begin_new_pos, base_pos;
1.1 etheisen 227: int c;
228: int endline;
1.5 shadchin 229: int backchars;
1.1 etheisen 230:
1.5 shadchin 231: get_back_line:
1.8 nicm 232: if (curr_pos == -1 || curr_pos <= ch_zero()) {
1.1 etheisen 233: null_line();
1.8 nicm 234: return (-1);
1.1 etheisen 235: }
1.5 shadchin 236: if (hilite_search == OPT_ONPLUS || is_filtering() || status_col)
1.8 nicm 237: prep_hilite((curr_pos < 3*size_linebuf) ?
238: 0 : curr_pos - 3*size_linebuf, curr_pos, -1);
239: if (ch_seek(curr_pos-1)) {
1.1 etheisen 240: null_line();
1.8 nicm 241: return (-1);
1.1 etheisen 242: }
243:
1.8 nicm 244: if (squeeze) {
1.1 etheisen 245: /*
246: * Find out if the "current" line was blank.
247: */
1.8 nicm 248: (void) ch_forw_get(); /* Skip the newline */
249: c = ch_forw_get(); /* First char of "current" line */
250: (void) ch_back_get(); /* Restore our position */
1.1 etheisen 251: (void) ch_back_get();
252:
1.8 nicm 253: if (c == '\n' || c == '\r') {
1.1 etheisen 254: /*
255: * The "current" line was blank.
256: * Skip over any preceding blank lines,
257: * since we skipped them in forw_line().
258: */
259: while ((c = ch_back_get()) == '\n' || c == '\r')
1.8 nicm 260: if (ABORT_SIGS()) {
1.1 etheisen 261: null_line();
1.8 nicm 262: return (-1);
1.1 etheisen 263: }
1.8 nicm 264: if (c == EOI) {
1.1 etheisen 265: null_line();
1.8 nicm 266: return (-1);
1.1 etheisen 267: }
268: (void) ch_forw_get();
269: }
270: }
271:
272: /*
273: * Scan backwards until we hit the beginning of the line.
274: */
1.8 nicm 275: for (;;) {
276: if (ABORT_SIGS()) {
1.1 etheisen 277: null_line();
1.8 nicm 278: return (-1);
1.1 etheisen 279: }
280: c = ch_back_get();
1.8 nicm 281: if (c == '\n') {
1.1 etheisen 282: /*
283: * This is the newline ending the previous line.
284: * We have hit the beginning of the line.
285: */
1.5 shadchin 286: base_pos = ch_tell() + 1;
1.1 etheisen 287: break;
288: }
1.8 nicm 289: if (c == EOI) {
1.1 etheisen 290: /*
291: * We have hit the beginning of the file.
292: * This must be the first line in the file.
293: * This must, of course, be the beginning of the line.
294: */
1.5 shadchin 295: base_pos = ch_tell();
1.1 etheisen 296: break;
297: }
298: }
299:
300: /*
301: * Now scan forwards from the beginning of this line.
302: * We keep discarding "printable lines" (based on screen width)
303: * until we reach the curr_pos.
304: *
305: * {{ This algorithm is pretty inefficient if the lines
1.8 nicm 306: * are much longer than the screen width,
1.1 etheisen 307: * but I don't know of any better way. }}
308: */
1.5 shadchin 309: new_pos = base_pos;
1.8 nicm 310: if (ch_seek(new_pos)) {
1.1 etheisen 311: null_line();
1.8 nicm 312: return (-1);
1.1 etheisen 313: }
1.4 millert 314: endline = FALSE;
1.5 shadchin 315: prewind();
316: plinenum(new_pos);
1.8 nicm 317: loop:
1.1 etheisen 318: begin_new_pos = new_pos;
319: (void) ch_seek(new_pos);
320:
1.8 nicm 321: do {
1.1 etheisen 322: c = ch_forw_get();
1.8 nicm 323: if (c == EOI || ABORT_SIGS()) {
1.1 etheisen 324: null_line();
1.8 nicm 325: return (-1);
1.1 etheisen 326: }
327: new_pos++;
1.8 nicm 328: if (c == '\n') {
1.5 shadchin 329: backchars = pflushmbc();
1.8 nicm 330: if (backchars > 0 && !chopline && hshift == 0) {
1.5 shadchin 331: backchars++;
332: goto shift;
333: }
1.4 millert 334: endline = TRUE;
1.1 etheisen 335: break;
336: }
1.5 shadchin 337: backchars = pappend(c, ch_tell()-1);
1.8 nicm 338: if (backchars > 0) {
1.1 etheisen 339: /*
340: * Got a full printable line, but we haven't
341: * reached our curr_pos yet. Discard the line
342: * and start a new one.
343: */
1.8 nicm 344: if (chopline || hshift > 0) {
1.4 millert 345: endline = TRUE;
346: quit_if_one_screen = FALSE;
1.1 etheisen 347: break;
348: }
1.5 shadchin 349: shift:
350: pshift_all();
1.8 nicm 351: while (backchars-- > 0) {
1.5 shadchin 352: (void) ch_back_get();
353: new_pos--;
354: }
1.1 etheisen 355: goto loop;
356: }
357: } while (new_pos < curr_pos);
358:
1.5 shadchin 359: pdone(endline, 0);
360:
1.8 nicm 361: if (is_filtered(base_pos)) {
1.5 shadchin 362: /*
363: * We don't want to display this line.
364: * Get the previous line.
365: */
366: curr_pos = begin_new_pos;
367: goto get_back_line;
368: }
369:
1.8 nicm 370: if (status_col && curr_pos > 0 &&
371: is_hilited(base_pos, curr_pos-1, 1, NULL))
1.5 shadchin 372: set_status_col('*');
1.1 etheisen 373:
374: return (begin_new_pos);
1.4 millert 375: }
376:
377: /*
378: * Set attnpos.
379: */
1.8 nicm 380: void
381: set_attnpos(off_t pos)
1.4 millert 382: {
383: int c;
384:
1.8 nicm 385: if (pos != -1) {
1.4 millert 386: if (ch_seek(pos))
387: return;
1.8 nicm 388: for (;;) {
1.4 millert 389: c = ch_forw_get();
390: if (c == EOI)
391: return;
392: if (c != '\n' && c != '\r')
393: break;
394: pos++;
395: }
396: }
397: start_attnpos = pos;
1.8 nicm 398: for (;;) {
1.4 millert 399: c = ch_forw_get();
400: pos++;
401: if (c == EOI || c == '\n' || c == '\r')
402: break;
403: }
404: end_attnpos = pos;
1.1 etheisen 405: }
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