contrib/less/linenum.c

12  * Code to handle displaying line numbers.
14  * Finding the line number of a given file position is rather tricky.
20  * So we use the function add_lnum to cache line numbers.
22  * line numbers when we run out of space in our table.  A line
24  * other line numbers.   For example, we'd rather keep lines
29  * The function currline() returns the line number of a given
31  * to cache the line number.  Therefore currline is occasionally
32  * called to make sure we cache line numbers often enough.
38  * Structure to keep track of a line number and the associated file position.
39  * A doubly-linked circular list of line numbers is kept ordered by line number.
47 	LINENUM line;			/* Line number */
50  * "gap" needs some explanation: the gap of any particular line number
53  * gap of a line number is the gap which would be introduced if this
54  * line number were deleted.  It is used to decide which one to replace
58 #define	NPOOL	200			/* Size of line number pool */
73  * Initialize the line number structures.
97 	anchor.line = 1;
119  * Add a new line number to the cache.
121  * FIRST character in the specified line.
139 		if (p->line == linenum)
170 	new->line = linenum;
209  * line number, print a message to tell the user what we're doing.
214 	ierror("Calculating line numbers", NULL_PARG);
245  * Turn off line numbers because the user has interrupted
246  * a lengthy line number calculation.
253 		 * We were displaying line numbers, so need to repaint.
261  * Find the line number associated with a given position.
274 		 * We're not using line numbers.
284 		 * Beginning of file is always line number 1.
295 		return (p->line);
299 	 * We start at the line we just found and start
320 		for (linenum = p->line, cpos = p->pos;  cpos < pos;  linenum++)
339 		 * If the given position is not at the start of a line,
340 		 * make sure we return the correct line number.
352 		for (linenum = p->line, cpos = p->pos;  cpos > pos;  linenum--)
376  * Find the position of a given line number.
394 	 * Find the entry nearest to the line number we want.
396 	for (p = anchor.next;  p != &anchor && p->line < linenum;  p = p->next)
398 	if (p->line == linenum)
402 	if (p == &anchor || linenum - p->prev->line < p->line - linenum)
410 		for (clinenum = p->line, cpos = p->pos;  clinenum < linenum;  clinenum++)
428 		for (clinenum = p->line, cpos = p->pos;  clinenum > linenum;  clinenum--)
448  * Return the line number of the "current" line.
449  * The argument "where" tells which line is to be considered
450  * the "current" line (e.g. TOP, BOTTOM, MIDDLE, etc).