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1.1 etheisen 1: /*
1.5 millert 2: * Copyright (C) 1984-2002 Mark Nudelman
1.1 etheisen 3: *
1.5 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: *
1.5 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: * Routines to manipulate the "line buffer".
14: * The line buffer holds a line of output as it is being built
15: * in preparation for output to the screen.
16: */
17:
18: #include "less.h"
19:
1.5 millert 20: #define IS_CONT(c) (((c) & 0xC0) == 0x80)
21:
22: public char *linebuf = NULL; /* Buffer which holds the current output line */
23: static char *attr = NULL; /* Extension of linebuf to hold attributes */
24: public int size_linebuf = 0; /* Size of line buffer (and attr buffer) */
25:
26: public int cshift; /* Current left-shift of output line buffer */
27: public int hshift; /* Desired left-shift of output line buffer */
28: public int tabstops[TABSTOP_MAX] = { 0 }; /* Custom tabstops */
29: public int ntabstops = 1; /* Number of tabstops */
30: public int tabdefault = 8; /* Default repeated tabstops */
1.1 etheisen 31:
32: static int curr; /* Index into linebuf */
33: static int column; /* Printable length, accounting for
34: backspaces, etc. */
35: static int overstrike; /* Next char should overstrike previous char */
1.5 millert 36: static int last_overstrike = AT_NORMAL;
1.1 etheisen 37: static int is_null_line; /* There is no current line */
1.5 millert 38: static int lmargin; /* Left margin */
39: static int hilites; /* Number of hilites in this line */
1.1 etheisen 40: static char pendc;
41: static POSITION pendpos;
1.5 millert 42: static char *end_ansi_chars;
1.1 etheisen 43:
44: static int do_append();
45:
46: extern int bs_mode;
47: extern int linenums;
48: extern int ctldisp;
49: extern int twiddle;
50: extern int binattr;
1.5 millert 51: extern int status_col;
1.1 etheisen 52: extern int auto_wrap, ignaw;
53: extern int bo_s_width, bo_e_width;
54: extern int ul_s_width, ul_e_width;
55: extern int bl_s_width, bl_e_width;
56: extern int so_s_width, so_e_width;
57: extern int sc_width, sc_height;
1.5 millert 58: extern int utf_mode;
59: extern POSITION start_attnpos;
60: extern POSITION end_attnpos;
61:
62: /*
63: * Initialize from environment variables.
64: */
65: public void
66: init_line()
67: {
68: end_ansi_chars = lgetenv("LESSANSIENDCHARS");
69: if (end_ansi_chars == NULL || *end_ansi_chars == '\0')
70: end_ansi_chars = "m";
71: linebuf = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
72: attr = (char *) ecalloc(LINEBUF_SIZE, sizeof(char));
73: size_linebuf = LINEBUF_SIZE;
74: }
75:
76: /*
77: * Expand the line buffer.
78: */
79: static int
80: expand_linebuf()
81: {
82: int new_size = size_linebuf + LINEBUF_SIZE;
83: char *new_buf = (char *) calloc(new_size, sizeof(char));
84: char *new_attr = (char *) calloc(new_size, sizeof(char));
85: if (new_buf == NULL || new_attr == NULL)
86: {
87: if (new_attr != NULL)
88: free(new_attr);
89: if (new_buf != NULL)
90: free(new_buf);
91: return 1;
92: }
93: memcpy(new_buf, linebuf, size_linebuf * sizeof(char));
94: memcpy(new_attr, attr, size_linebuf * sizeof(char));
95: free(attr);
96: free(linebuf);
97: linebuf = new_buf;
98: attr = new_attr;
99: size_linebuf = new_size;
100: return 0;
101: }
1.1 etheisen 102:
103: /*
104: * Rewind the line buffer.
105: */
106: public void
107: prewind()
108: {
109: curr = 0;
110: column = 0;
111: overstrike = 0;
112: is_null_line = 0;
113: pendc = '\0';
1.5 millert 114: lmargin = 0;
115: if (status_col)
116: lmargin += 1;
117: #if HILITE_SEARCH
118: hilites = 0;
119: #endif
1.1 etheisen 120: }
121:
122: /*
123: * Insert the line number (of the given position) into the line buffer.
124: */
125: public void
126: plinenum(pos)
127: POSITION pos;
128: {
1.5 millert 129: register LINENUM linenum = 0;
130: register int i;
131:
132: if (linenums == OPT_ONPLUS)
133: {
134: /*
135: * Get the line number and put it in the current line.
136: * {{ Note: since find_linenum calls forw_raw_line,
137: * it may seek in the input file, requiring the caller
138: * of plinenum to re-seek if necessary. }}
139: * {{ Since forw_raw_line modifies linebuf, we must
140: * do this first, before storing anything in linebuf. }}
141: */
142: linenum = find_linenum(pos);
143: }
1.1 etheisen 144:
145: /*
1.5 millert 146: * Display a status column if the -J option is set.
1.1 etheisen 147: */
1.5 millert 148: if (status_col)
149: {
150: linebuf[curr] = ' ';
151: if (start_attnpos != NULL_POSITION &&
152: pos >= start_attnpos && pos < end_attnpos)
153: attr[curr] = AT_STANDOUT;
154: else
155: attr[curr] = 0;
156: curr++;
157: column++;
158: }
1.1 etheisen 159: /*
1.5 millert 160: * Display the line number at the start of each line
161: * if the -N option is set.
1.1 etheisen 162: */
1.5 millert 163: if (linenums == OPT_ONPLUS)
164: {
165: char buf[INT_STRLEN_BOUND(pos) + 2];
166: int n;
1.1 etheisen 167:
1.5 millert 168: linenumtoa(linenum, buf, sizeof(buf));
169: n = strlen(buf);
170: if (n < MIN_LINENUM_WIDTH)
171: n = MIN_LINENUM_WIDTH;
1.6 ! millert 172: snprintf(linebuf+curr, size_linebuf-curr, "%*s ", n, buf);
1.5 millert 173: n++; /* One space after the line number. */
174: for (i = 0; i < n; i++)
175: attr[curr+i] = AT_NORMAL;
176: curr += n;
177: column += n;
178: lmargin += n;
179: }
1.1 etheisen 180:
181: /*
1.5 millert 182: * Append enough spaces to bring us to the lmargin.
1.1 etheisen 183: */
1.5 millert 184: while (column < lmargin)
1.1 etheisen 185: {
186: linebuf[curr] = ' ';
187: attr[curr++] = AT_NORMAL;
188: column++;
1.5 millert 189: }
190: }
191:
192: /*
193: * Determine how many characters are required to shift N columns.
194: */
195: static int
196: shift_chars(s, len)
197: char *s;
198: int len;
199: {
200: char *p = s;
201:
202: /*
203: * Each char counts for one column, except ANSI color escape
204: * sequences use no columns since they don't move the cursor.
205: */
206: while (*p != '\0' && len > 0)
207: {
208: if (*p++ != ESC)
209: {
210: len--;
211: } else
212: {
213: while (*p != '\0')
214: {
215: if (is_ansi_end(*p++))
216: break;
217: }
218: }
219: }
220: return (p - s);
221: }
222:
223: /*
224: * Determine how many characters are required to shift N columns (UTF version).
225: * {{ FIXME: what about color escape sequences in UTF mode? }}
226: */
227: static int
228: utf_shift_chars(s, len)
229: char *s;
230: int len;
231: {
232: int ulen = 0;
233:
234: while (*s != '\0' && len > 0)
235: {
236: if (!IS_CONT(*s))
237: len--;
238: s++;
239: ulen++;
240: }
241: while (IS_CONT(*s))
242: {
243: s++;
244: ulen++;
245: }
246: return (ulen);
247: }
248:
249: /*
250: * Shift the input line left.
251: * This means discarding N printable chars at the start of the buffer.
252: */
253: static void
254: pshift(shift)
255: int shift;
256: {
257: int i;
258: int nchars;
259:
260: if (shift > column - lmargin)
261: shift = column - lmargin;
262: if (shift > curr - lmargin)
263: shift = curr - lmargin;
264:
265: if (utf_mode)
266: nchars = utf_shift_chars(linebuf + lmargin, shift);
267: else
268: nchars = shift_chars(linebuf + lmargin, shift);
269: if (nchars > curr)
270: nchars = curr;
271: for (i = 0; i < curr - nchars; i++)
272: {
273: linebuf[lmargin + i] = linebuf[lmargin + i + nchars];
274: attr[lmargin + i] = attr[lmargin + i + nchars];
275: }
276: curr -= nchars;
277: column -= shift;
278: cshift += shift;
1.1 etheisen 279: }
280:
281: /*
282: * Return the printing width of the start (enter) sequence
283: * for a given character attribute.
284: */
1.5 millert 285: static int
1.1 etheisen 286: attr_swidth(a)
287: int a;
288: {
289: switch (a)
290: {
291: case AT_BOLD: return (bo_s_width);
292: case AT_UNDERLINE: return (ul_s_width);
293: case AT_BLINK: return (bl_s_width);
294: case AT_STANDOUT: return (so_s_width);
295: }
296: return (0);
297: }
298:
299: /*
300: * Return the printing width of the end (exit) sequence
301: * for a given character attribute.
302: */
1.5 millert 303: static int
1.1 etheisen 304: attr_ewidth(a)
305: int a;
306: {
307: switch (a)
308: {
309: case AT_BOLD: return (bo_e_width);
310: case AT_UNDERLINE: return (ul_e_width);
311: case AT_BLINK: return (bl_e_width);
312: case AT_STANDOUT: return (so_e_width);
313: }
314: return (0);
315: }
316:
317: /*
318: * Return the printing width of a given character and attribute,
319: * if the character were added to the current position in the line buffer.
320: * Adding a character with a given attribute may cause an enter or exit
321: * attribute sequence to be inserted, so this must be taken into account.
322: */
323: static int
324: pwidth(c, a)
325: int c;
326: int a;
327: {
1.5 millert 328: register int w;
329:
330: if (utf_mode && IS_CONT(c))
331: return (0);
1.1 etheisen 332:
333: if (c == '\b')
334: /*
335: * Backspace moves backwards one position.
336: */
337: return (-1);
338:
339: if (control_char(c))
340: /*
341: * Control characters do unpredicatable things,
342: * so we don't even try to guess; say it doesn't move.
343: * This can only happen if the -r flag is in effect.
344: */
345: return (0);
346:
347: /*
348: * Other characters take one space,
349: * plus the width of any attribute enter/exit sequence.
350: */
351: w = 1;
352: if (curr > 0 && attr[curr-1] != a)
353: w += attr_ewidth(attr[curr-1]);
354: if (a && (curr == 0 || attr[curr-1] != a))
355: w += attr_swidth(a);
356: return (w);
357: }
358:
359: /*
360: * Delete the previous character in the line buffer.
361: */
362: static void
363: backc()
364: {
365: curr--;
366: column -= pwidth(linebuf[curr], attr[curr]);
367: }
368:
369: /*
1.5 millert 370: * Are we currently within a recognized ANSI escape sequence?
371: */
372: static int
373: in_ansi_esc_seq()
374: {
375: int i;
376:
377: /*
378: * Search backwards for either an ESC (which means we ARE in a seq);
379: * or an end char (which means we're NOT in a seq).
380: */
381: for (i = curr-1; i >= 0; i--)
382: {
383: if (linebuf[i] == ESC)
384: return (1);
385: if (is_ansi_end(linebuf[i]))
386: return (0);
387: }
388: return (0);
389: }
390:
391: /*
392: * Is a character the end of an ANSI escape sequence?
393: */
394: public int
395: is_ansi_end(c)
396: char c;
397: {
398: return (strchr(end_ansi_chars, c) != NULL);
399: }
400:
401: /*
1.1 etheisen 402: * Append a character and attribute to the line buffer.
403: */
1.5 millert 404: #define STORE_CHAR(c,a,pos) \
405: do { if (store_char((c),(a),(pos))) return (1); else curr++; } while (0)
406:
1.1 etheisen 407: static int
1.5 millert 408: store_char(c, a, pos)
1.1 etheisen 409: int c;
410: int a;
411: POSITION pos;
412: {
1.5 millert 413: register int w;
1.1 etheisen 414:
1.5 millert 415: if (a != AT_NORMAL)
416: last_overstrike = a;
1.1 etheisen 417: #if HILITE_SEARCH
418: if (is_hilited(pos, pos+1, 0))
1.5 millert 419: {
1.1 etheisen 420: /*
421: * This character should be highlighted.
422: * Override the attribute passed in.
423: */
424: a = AT_STANDOUT;
1.5 millert 425: hilites++;
426: }
1.1 etheisen 427: #endif
1.5 millert 428: if (ctldisp == OPT_ONPLUS && in_ansi_esc_seq())
429: w = 0;
430: else
431: w = pwidth(c, a);
432: if (ctldisp != OPT_ON && column + w + attr_ewidth(a) > sc_width)
1.1 etheisen 433: /*
434: * Won't fit on screen.
435: */
436: return (1);
437:
1.5 millert 438: if (curr >= size_linebuf-2)
439: {
1.1 etheisen 440: /*
441: * Won't fit in line buffer.
1.5 millert 442: * Try to expand it.
1.1 etheisen 443: */
1.5 millert 444: if (expand_linebuf())
445: return (1);
446: }
1.1 etheisen 447:
448: /*
449: * Special handling for "magic cookie" terminals.
450: * If an attribute enter/exit sequence has a printing width > 0,
451: * and the sequence is adjacent to a space, delete the space.
452: * We just mark the space as invisible, to avoid having too
453: * many spaces deleted.
454: * {{ Note that even if the attribute width is > 1, we
455: * delete only one space. It's not worth trying to do more.
456: * It's hardly worth doing this much. }}
457: */
458: if (curr > 0 && a != AT_NORMAL &&
459: linebuf[curr-1] == ' ' && attr[curr-1] == AT_NORMAL &&
460: attr_swidth(a) > 0)
461: {
462: /*
463: * We are about to append an enter-attribute sequence
464: * just after a space. Delete the space.
465: */
466: attr[curr-1] = AT_INVIS;
467: column--;
468: } else if (curr > 0 && attr[curr-1] != AT_NORMAL &&
469: attr[curr-1] != AT_INVIS && c == ' ' && a == AT_NORMAL &&
470: attr_ewidth(attr[curr-1]) > 0)
471: {
472: /*
473: * We are about to append a space just after an
474: * exit-attribute sequence. Delete the space.
475: */
476: a = AT_INVIS;
477: column--;
478: }
479: /* End of magic cookie handling. */
480:
481: linebuf[curr] = c;
482: attr[curr] = a;
483: column += w;
484: return (0);
485: }
486:
487: /*
1.5 millert 488: * Append a tab to the line buffer.
489: * Store spaces to represent the tab.
490: */
491: #define STORE_TAB(a,pos) \
492: do { if (store_tab((a),(pos))) return (1); } while (0)
493:
494: static int
495: store_tab(attr, pos)
496: int attr;
497: POSITION pos;
498: {
499: int to_tab = column + cshift - lmargin;
500: int i;
501:
502: if (ntabstops < 2 || to_tab >= tabstops[ntabstops-1])
503: to_tab = tabdefault -
504: ((to_tab - tabstops[ntabstops-1]) % tabdefault);
505: else
506: {
507: for (i = ntabstops - 2; i >= 0; i--)
508: if (to_tab >= tabstops[i])
509: break;
510: to_tab = tabstops[i+1] - to_tab;
511: }
512:
513: do {
514: STORE_CHAR(' ', attr, pos);
515: } while (--to_tab > 0);
516: return 0;
517: }
518:
519: /*
1.1 etheisen 520: * Append a character to the line buffer.
521: * Expand tabs into spaces, handle underlining, boldfacing, etc.
522: * Returns 0 if ok, 1 if couldn't fit in buffer.
523: */
524: public int
525: pappend(c, pos)
1.5 millert 526: register int c;
1.1 etheisen 527: POSITION pos;
528: {
1.5 millert 529: int r;
530:
1.1 etheisen 531: if (pendc)
532: {
533: if (do_append(pendc, pendpos))
534: /*
535: * Oops. We've probably lost the char which
536: * was in pendc, since caller won't back up.
537: */
538: return (1);
539: pendc = '\0';
540: }
541:
542: if (c == '\r' && bs_mode == BS_SPECIAL)
543: {
544: /*
545: * Don't put the CR into the buffer until we see
546: * the next char. If the next char is a newline,
547: * discard the CR.
548: */
549: pendc = c;
550: pendpos = pos;
551: return (0);
552: }
553:
1.5 millert 554: r = do_append(c, pos);
555: /*
556: * If we need to shift the line, do it.
557: * But wait until we get to at least the middle of the screen,
558: * so shifting it doesn't affect the chars we're currently
559: * pappending. (Bold & underline can get messed up otherwise.)
560: */
561: if (cshift < hshift && column > sc_width / 2)
562: {
563: linebuf[curr] = '\0';
564: pshift(hshift - cshift);
565: }
566: return (r);
1.1 etheisen 567: }
568:
1.5 millert 569: #define IS_UTF8_4BYTE(c) ( ((c) & 0xf8) == 0xf0 )
570: #define IS_UTF8_3BYTE(c) ( ((c) & 0xf0) == 0xe0 )
571: #define IS_UTF8_2BYTE(c) ( ((c) & 0xe0) == 0xc0 )
572: #define IS_UTF8_TRAIL(c) ( ((c) & 0xc0) == 0x80 )
573:
1.1 etheisen 574: static int
575: do_append(c, pos)
576: int c;
577: POSITION pos;
578: {
1.5 millert 579: register char *s;
580: register int a;
1.1 etheisen 581:
1.5 millert 582: #define STOREC(c,a) \
583: if ((c) == '\t') STORE_TAB((a),pos); else STORE_CHAR((c),(a),pos)
1.1 etheisen 584:
1.5 millert 585: if (c == '\b')
586: {
587: switch (bs_mode)
588: {
589: case BS_NORMAL:
590: STORE_CHAR(c, AT_NORMAL, pos);
591: break;
592: case BS_CONTROL:
593: goto do_control_char;
594: case BS_SPECIAL:
595: if (curr == 0)
596: break;
597: backc();
598: overstrike = 1;
599: break;
600: }
601: } else if (overstrike)
1.1 etheisen 602: {
603: /*
604: * Overstrike the character at the current position
605: * in the line buffer. This will cause either
606: * underline (if a "_" is overstruck),
607: * bold (if an identical character is overstruck),
608: * or just deletion of the character in the buffer.
609: */
1.5 millert 610: overstrike--;
611: if (utf_mode && IS_UTF8_4BYTE(c) && curr > 2 && (char)c == linebuf[curr-3])
612: {
613: backc();
614: backc();
615: backc();
616: STORE_CHAR(linebuf[curr], AT_BOLD, pos);
617: overstrike = 3;
618: } else if (utf_mode && (IS_UTF8_3BYTE(c) || (overstrike==2 && IS_UTF8_TRAIL(c))) && curr > 1 && (char)c == linebuf[curr-2])
619: {
620: backc();
621: backc();
622: STORE_CHAR(linebuf[curr], AT_BOLD, pos);
623: overstrike = 2;
624: } else if (utf_mode && curr > 0 && (IS_UTF8_2BYTE(c) || (overstrike==1 && IS_UTF8_TRAIL(c))) && (char)c == linebuf[curr-1])
625: {
626: backc();
627: STORE_CHAR(linebuf[curr], AT_BOLD, pos);
628: overstrike = 1;
629: } else if (utf_mode && curr > 0 && IS_UTF8_TRAIL(c) && attr[curr-1] == AT_UNDERLINE)
630: {
631: STOREC(c, AT_UNDERLINE);
632: } else if ((char)c == linebuf[curr])
633: {
634: /*
635: * Overstriking a char with itself means make it bold.
636: * But overstriking an underscore with itself is
637: * ambiguous. It could mean make it bold, or
638: * it could mean make it underlined.
639: * Use the previous overstrike to resolve it.
640: */
641: if (c == '_' && last_overstrike != AT_NORMAL)
642: STOREC(c, last_overstrike);
643: else
644: STOREC(c, AT_BOLD);
645: } else if (c == '_')
646: {
647: if (utf_mode)
648: {
649: int i;
650: for (i = 0; i < 5; i++)
651: {
652: if (curr <= i || !IS_CONT(linebuf[curr-i]))
653: break;
654: attr[curr-i-1] = AT_UNDERLINE;
655: }
656: }
1.1 etheisen 657: STOREC(linebuf[curr], AT_UNDERLINE);
1.5 millert 658: } else if (linebuf[curr] == '_')
659: {
660: if (utf_mode)
661: {
662: if (IS_UTF8_2BYTE(c))
663: overstrike = 1;
664: else if (IS_UTF8_3BYTE(c))
665: overstrike = 2;
666: else if (IS_UTF8_4BYTE(c))
667: overstrike = 3;
668: }
1.1 etheisen 669: STOREC(c, AT_UNDERLINE);
1.5 millert 670: } else if (control_char(c))
1.1 etheisen 671: goto do_control_char;
672: else
673: STOREC(c, AT_NORMAL);
1.5 millert 674: } else if (c == '\t')
1.1 etheisen 675: {
1.5 millert 676: /*
677: * Expand a tab into spaces.
678: */
1.1 etheisen 679: switch (bs_mode)
680: {
681: case BS_CONTROL:
682: goto do_control_char;
1.5 millert 683: case BS_NORMAL:
1.1 etheisen 684: case BS_SPECIAL:
1.5 millert 685: STORE_TAB(AT_NORMAL, pos);
1.1 etheisen 686: break;
687: }
688: } else if (control_char(c))
689: {
690: do_control_char:
1.5 millert 691: if (ctldisp == OPT_ON || (ctldisp == OPT_ONPLUS && c == ESC))
1.1 etheisen 692: {
693: /*
694: * Output as a normal character.
695: */
1.5 millert 696: STORE_CHAR(c, AT_NORMAL, pos);
1.1 etheisen 697: } else
698: {
699: /*
700: * Convert to printable representation.
701: */
702: s = prchar(c);
703: a = binattr;
704:
705: /*
706: * Make sure we can get the entire representation
707: * of the character on this line.
708: */
709: if (column + (int) strlen(s) +
710: attr_swidth(a) + attr_ewidth(a) > sc_width)
711: return (1);
712:
713: for ( ; *s != 0; s++)
1.5 millert 714: STORE_CHAR(*s, a, pos);
1.1 etheisen 715: }
716: } else
717: {
718: STOREC(c, AT_NORMAL);
719: }
720:
721: return (0);
722: }
723:
724: /*
725: * Terminate the line in the line buffer.
726: */
727: public void
728: pdone(endline)
729: int endline;
730: {
731: if (pendc && (pendc != '\r' || !endline))
732: /*
733: * If we had a pending character, put it in the buffer.
734: * But discard a pending CR if we are at end of line
735: * (that is, discard the CR in a CR/LF sequence).
736: */
737: (void) do_append(pendc, pendpos);
738:
739: /*
1.5 millert 740: * Make sure we've shifted the line, if we need to.
741: */
742: if (cshift < hshift)
743: pshift(hshift - cshift);
744:
745: /*
1.1 etheisen 746: * Add a newline if necessary,
747: * and append a '\0' to the end of the line.
748: */
1.5 millert 749: if (column < sc_width || !auto_wrap || ignaw || ctldisp == OPT_ON)
1.1 etheisen 750: {
751: linebuf[curr] = '\n';
752: attr[curr] = AT_NORMAL;
753: curr++;
754: }
755: linebuf[curr] = '\0';
756: attr[curr] = AT_NORMAL;
1.5 millert 757:
758: #if HILITE_SEARCH
759: if (status_col && hilites > 0)
760: {
761: linebuf[0] = '*';
762: attr[0] = AT_STANDOUT;
763: }
764: #endif
765: /*
766: * If we are done with this line, reset the current shift.
767: */
768: if (endline)
769: cshift = 0;
1.1 etheisen 770: }
771:
772: /*
773: * Get a character from the current line.
774: * Return the character as the function return value,
775: * and the character attribute in *ap.
776: */
777: public int
778: gline(i, ap)
1.5 millert 779: register int i;
780: register int *ap;
1.1 etheisen 781: {
782: char *s;
783:
784: if (is_null_line)
785: {
786: /*
787: * If there is no current line, we pretend the line is
788: * either "~" or "", depending on the "twiddle" flag.
789: */
1.5 millert 790: *ap = AT_BOLD;
1.1 etheisen 791: s = (twiddle) ? "~\n" : "\n";
792: return (s[i]);
793: }
794:
795: *ap = attr[i];
796: return (linebuf[i] & 0377);
797: }
798:
799: /*
800: * Indicate that there is no current line.
801: */
802: public void
803: null_line()
804: {
805: is_null_line = 1;
1.5 millert 806: cshift = 0;
1.1 etheisen 807: }
808:
809: /*
810: * Analogous to forw_line(), but deals with "raw lines":
811: * lines which are not split for screen width.
812: * {{ This is supposed to be more efficient than forw_line(). }}
813: */
814: public POSITION
815: forw_raw_line(curr_pos, linep)
816: POSITION curr_pos;
817: char **linep;
818: {
1.5 millert 819: register int n;
820: register int c;
1.1 etheisen 821: POSITION new_pos;
822:
823: if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
824: (c = ch_forw_get()) == EOI)
825: return (NULL_POSITION);
826:
1.5 millert 827: n = 0;
1.1 etheisen 828: for (;;)
829: {
830: if (c == '\n' || c == EOI)
831: {
832: new_pos = ch_tell();
833: break;
834: }
1.5 millert 835: if (n >= size_linebuf-1)
1.1 etheisen 836: {
1.5 millert 837: if (expand_linebuf())
838: {
839: /*
840: * Overflowed the input buffer.
841: * Pretend the line ended here.
842: */
843: new_pos = ch_tell() - 1;
844: break;
845: }
1.1 etheisen 846: }
1.5 millert 847: linebuf[n++] = c;
1.1 etheisen 848: c = ch_forw_get();
849: }
1.5 millert 850: linebuf[n] = '\0';
1.1 etheisen 851: if (linep != NULL)
852: *linep = linebuf;
853: return (new_pos);
854: }
855:
856: /*
857: * Analogous to back_line(), but deals with "raw lines".
858: * {{ This is supposed to be more efficient than back_line(). }}
859: */
860: public POSITION
861: back_raw_line(curr_pos, linep)
862: POSITION curr_pos;
863: char **linep;
864: {
1.5 millert 865: register int n;
866: register int c;
1.1 etheisen 867: POSITION new_pos;
868:
869: if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
870: ch_seek(curr_pos-1))
871: return (NULL_POSITION);
872:
1.5 millert 873: n = size_linebuf;
874: linebuf[--n] = '\0';
1.1 etheisen 875: for (;;)
876: {
877: c = ch_back_get();
878: if (c == '\n')
879: {
880: /*
881: * This is the newline ending the previous line.
882: * We have hit the beginning of the line.
883: */
884: new_pos = ch_tell() + 1;
885: break;
886: }
887: if (c == EOI)
888: {
889: /*
890: * We have hit the beginning of the file.
891: * This must be the first line in the file.
892: * This must, of course, be the beginning of the line.
893: */
894: new_pos = ch_zero();
895: break;
896: }
1.5 millert 897: if (n <= 0)
1.1 etheisen 898: {
1.5 millert 899: int old_size_linebuf = size_linebuf;
900: char *fm;
901: char *to;
902: if (expand_linebuf())
903: {
904: /*
905: * Overflowed the input buffer.
906: * Pretend the line ended here.
907: */
908: new_pos = ch_tell() + 1;
909: break;
910: }
1.1 etheisen 911: /*
1.5 millert 912: * Shift the data to the end of the new linebuf.
1.1 etheisen 913: */
1.5 millert 914: for (fm = linebuf + old_size_linebuf,
915: to = linebuf + size_linebuf;
916: fm >= linebuf; fm--, to--)
917: *to = *fm;
918: n = size_linebuf - old_size_linebuf;
1.1 etheisen 919: }
1.5 millert 920: linebuf[--n] = c;
1.1 etheisen 921: }
922: if (linep != NULL)
1.5 millert 923: *linep = &linebuf[n];
1.1 etheisen 924: return (new_pos);
925: }