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1.1 ! etheisen 1: /*
! 2: * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
! 3: * All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice in the documentation and/or other materials provided with
! 12: * the distribution.
! 13: *
! 14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
! 15: * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 16: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
! 17: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
! 18: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! 19: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
! 20: * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
! 21: * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
! 22: * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
! 23: * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
! 24: * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
! 25: */
! 26:
! 27:
! 28: /*
! 29: * High level routines dealing with getting lines of input
! 30: * from the file being viewed.
! 31: *
! 32: * When we speak of "lines" here, we mean PRINTABLE lines;
! 33: * lines processed with respect to the screen width.
! 34: * We use the term "raw line" to refer to lines simply
! 35: * delimited by newlines; not processed with respect to screen width.
! 36: */
! 37:
! 38: #include "less.h"
! 39:
! 40: extern int squeeze;
! 41: extern int chopline;
! 42: extern int sigs;
! 43: #if HILITE_SEARCH
! 44: extern int hilite_search;
! 45: extern int size_linebuf;
! 46: #endif
! 47:
! 48: /*
! 49: * Get the next line.
! 50: * A "current" position is passed and a "new" position is returned.
! 51: * The current position is the position of the first character of
! 52: * a line. The new position is the position of the first character
! 53: * of the NEXT line. The line obtained is the line starting at curr_pos.
! 54: */
! 55: public POSITION
! 56: forw_line(curr_pos)
! 57: POSITION curr_pos;
! 58: {
! 59: POSITION new_pos;
! 60: register int c;
! 61: int blankline;
! 62: int endline;
! 63:
! 64: if (curr_pos == NULL_POSITION)
! 65: {
! 66: null_line();
! 67: return (NULL_POSITION);
! 68: }
! 69: #if HILITE_SEARCH
! 70: if (hilite_search == OPT_ONPLUS)
! 71: prep_hilite(curr_pos, curr_pos + 3*size_linebuf);
! 72: #endif
! 73: if (ch_seek(curr_pos))
! 74: {
! 75: null_line();
! 76: return (NULL_POSITION);
! 77: }
! 78:
! 79: prewind();
! 80: plinenum(curr_pos);
! 81: (void) ch_seek(curr_pos);
! 82:
! 83: c = ch_forw_get();
! 84: if (c == EOI)
! 85: {
! 86: null_line();
! 87: return (NULL_POSITION);
! 88: }
! 89: blankline = (c == '\n' || c == '\r');
! 90:
! 91: for (;;)
! 92: {
! 93: if (ABORT_SIGS())
! 94: {
! 95: null_line();
! 96: return (NULL_POSITION);
! 97: }
! 98: if (c == '\n' || c == EOI)
! 99: {
! 100: /*
! 101: * End of the line.
! 102: */
! 103: new_pos = ch_tell();
! 104: endline = 1;
! 105: break;
! 106: }
! 107:
! 108: /*
! 109: * Append the char to the line and get the next char.
! 110: */
! 111: if (pappend(c, ch_tell()-1))
! 112: {
! 113: /*
! 114: * The char won't fit in the line; the line
! 115: * is too long to print in the screen width.
! 116: * End the line here.
! 117: */
! 118: if (chopline)
! 119: {
! 120: do
! 121: {
! 122: c = ch_forw_get();
! 123: } while (c != '\n' && c != EOI);
! 124: new_pos = ch_tell();
! 125: endline = 1;
! 126: } else
! 127: {
! 128: new_pos = ch_tell() - 1;
! 129: endline = 0;
! 130: }
! 131: break;
! 132: }
! 133: c = ch_forw_get();
! 134: }
! 135: pdone(endline);
! 136:
! 137: if (squeeze && blankline)
! 138: {
! 139: /*
! 140: * This line is blank.
! 141: * Skip down to the last contiguous blank line
! 142: * and pretend it is the one which we are returning.
! 143: */
! 144: while ((c = ch_forw_get()) == '\n' || c == '\r')
! 145: if (ABORT_SIGS())
! 146: {
! 147: null_line();
! 148: return (NULL_POSITION);
! 149: }
! 150: if (c != EOI)
! 151: (void) ch_back_get();
! 152: new_pos = ch_tell();
! 153: }
! 154:
! 155: return (new_pos);
! 156: }
! 157:
! 158: /*
! 159: * Get the previous line.
! 160: * A "current" position is passed and a "new" position is returned.
! 161: * The current position is the position of the first character of
! 162: * a line. The new position is the position of the first character
! 163: * of the PREVIOUS line. The line obtained is the one starting at new_pos.
! 164: */
! 165: public POSITION
! 166: back_line(curr_pos)
! 167: POSITION curr_pos;
! 168: {
! 169: POSITION new_pos, begin_new_pos;
! 170: int c;
! 171: int endline;
! 172:
! 173: if (curr_pos == NULL_POSITION || curr_pos <= ch_zero())
! 174: {
! 175: null_line();
! 176: return (NULL_POSITION);
! 177: }
! 178: #if HILITE_SEARCH
! 179: if (hilite_search == OPT_ONPLUS)
! 180: prep_hilite((curr_pos < 3*size_linebuf) ?
! 181: 0 : curr_pos - 3*size_linebuf, curr_pos);
! 182: #endif
! 183: if (ch_seek(curr_pos-1))
! 184: {
! 185: null_line();
! 186: return (NULL_POSITION);
! 187: }
! 188:
! 189: if (squeeze)
! 190: {
! 191: /*
! 192: * Find out if the "current" line was blank.
! 193: */
! 194: (void) ch_forw_get(); /* Skip the newline */
! 195: c = ch_forw_get(); /* First char of "current" line */
! 196: (void) ch_back_get(); /* Restore our position */
! 197: (void) ch_back_get();
! 198:
! 199: if (c == '\n' || c == '\r')
! 200: {
! 201: /*
! 202: * The "current" line was blank.
! 203: * Skip over any preceding blank lines,
! 204: * since we skipped them in forw_line().
! 205: */
! 206: while ((c = ch_back_get()) == '\n' || c == '\r')
! 207: if (ABORT_SIGS())
! 208: {
! 209: null_line();
! 210: return (NULL_POSITION);
! 211: }
! 212: if (c == EOI)
! 213: {
! 214: null_line();
! 215: return (NULL_POSITION);
! 216: }
! 217: (void) ch_forw_get();
! 218: }
! 219: }
! 220:
! 221: /*
! 222: * Scan backwards until we hit the beginning of the line.
! 223: */
! 224: for (;;)
! 225: {
! 226: if (ABORT_SIGS())
! 227: {
! 228: null_line();
! 229: return (NULL_POSITION);
! 230: }
! 231: c = ch_back_get();
! 232: if (c == '\n')
! 233: {
! 234: /*
! 235: * This is the newline ending the previous line.
! 236: * We have hit the beginning of the line.
! 237: */
! 238: new_pos = ch_tell() + 1;
! 239: break;
! 240: }
! 241: if (c == EOI)
! 242: {
! 243: /*
! 244: * We have hit the beginning of the file.
! 245: * This must be the first line in the file.
! 246: * This must, of course, be the beginning of the line.
! 247: */
! 248: new_pos = ch_tell();
! 249: break;
! 250: }
! 251: }
! 252:
! 253: /*
! 254: * Now scan forwards from the beginning of this line.
! 255: * We keep discarding "printable lines" (based on screen width)
! 256: * until we reach the curr_pos.
! 257: *
! 258: * {{ This algorithm is pretty inefficient if the lines
! 259: * are much longer than the screen width,
! 260: * but I don't know of any better way. }}
! 261: */
! 262: if (ch_seek(new_pos))
! 263: {
! 264: null_line();
! 265: return (NULL_POSITION);
! 266: }
! 267: endline = 0;
! 268: loop:
! 269: begin_new_pos = new_pos;
! 270: prewind();
! 271: plinenum(new_pos);
! 272: (void) ch_seek(new_pos);
! 273:
! 274: do
! 275: {
! 276: c = ch_forw_get();
! 277: if (c == EOI || ABORT_SIGS())
! 278: {
! 279: null_line();
! 280: return (NULL_POSITION);
! 281: }
! 282: new_pos++;
! 283: if (c == '\n')
! 284: {
! 285: endline = 1;
! 286: break;
! 287: }
! 288: if (pappend(c, ch_tell()-1))
! 289: {
! 290: /*
! 291: * Got a full printable line, but we haven't
! 292: * reached our curr_pos yet. Discard the line
! 293: * and start a new one.
! 294: */
! 295: if (chopline)
! 296: {
! 297: endline = 1;
! 298: break;
! 299: }
! 300: pdone(0);
! 301: (void) ch_back_get();
! 302: new_pos--;
! 303: goto loop;
! 304: }
! 305: } while (new_pos < curr_pos);
! 306:
! 307: pdone(endline);
! 308:
! 309: return (begin_new_pos);
! 310: }