Import the [now] dual licensed version 3.5.4 of less. It is

distributed under your choice of the GPL or a BSD style license.

Reviewed by:	peter
Obtained from:	http://home.flash.net/~marknu/less/

1 files changed, 521 insertions, 0 deletions

diff --git a/contrib/less/prompt.c b/contrib/less/prompt.c
new file mode 100644
index 0000000..1448021
--- /dev/null
+++ b/contrib/less/prompt.c
@@ -0,0 +1,521 @@
+/*
+ * Copyright (C) 1984-2000  Mark Nudelman
+ *
+ * You may distribute under the terms of either the GNU General Public
+ * License or the Less License, as specified in the README file.
+ *
+ * For more information about less, or for information on how to 
+ * contact the author, see the README file.
+ */
+
+
+/*
+ * Prompting and other messages.
+ * There are three flavors of prompts, SHORT, MEDIUM and LONG,
+ * selected by the -m/-M options.
+ * There is also the "equals message", printed by the = command.
+ * A prompt is a message composed of various pieces, such as the 
+ * name of the file being viewed, the percentage into the file, etc.
+ */
+
+#include "less.h"
+#include "position.h"
+
+extern int pr_type;
+extern int hit_eof;
+extern int new_file;
+extern int sc_width;
+extern int so_s_width, so_e_width;
+extern int linenums;
+extern int hshift;
+extern int sc_height;
+extern int jump_sline;
+extern IFILE curr_ifile;
+#if EDITOR
+extern char *editor;
+extern char *editproto;
+#endif
+
+/*
+ * Prototypes for the three flavors of prompts.
+ * These strings are expanded by pr_expand().
+ */
+static constant char s_proto[] =
+  "?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\\: %x..%t";
+static constant char m_proto[] =
+  "?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
+static constant char M_proto[] =
+  "?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t";
+static constant char e_proto[] =
+  "?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
+static constant char h_proto[] =
+  "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
+
+public char *prproto[3];
+public char constant *eqproto = e_proto;
+public char constant *hproto = h_proto;
+
+static char message[PROMPT_SIZE];
+static char *mp;
+
+/*
+ * Initialize the prompt prototype strings.
+ */
+	public void
+init_prompt()
+{
+	prproto[0] = save(s_proto);
+	prproto[1] = save(m_proto);
+	prproto[2] = save(M_proto);
+	eqproto = save(e_proto);
+	hproto = save(h_proto);
+}
+
+/*
+ * Append a string to the end of the message.
+ */
+	static void
+ap_str(s)
+	char *s;
+{
+	int len;
+
+	len = strlen(s);
+	if (mp + len >= message + PROMPT_SIZE)
+		len = message + PROMPT_SIZE - mp - 1;
+	strncpy(mp, s, len);
+	mp += len;
+	*mp = '\0';
+}
+
+/*
+ * Append a character to the end of the message.
+ */
+	static void
+ap_char(c)
+	char c;
+{
+	char buf[2];
+
+	buf[0] = c;
+	buf[1] = '\0';
+	ap_str(buf);
+}
+
+/*
+ * Append a POSITION (as a decimal integer) to the end of the message.
+ */
+	static void
+ap_pos(pos)
+	POSITION pos;
+{
+	char buf[MAX_PRINT_POSITION];
+
+	sprintf(buf, PR_POSITION, pos);
+	ap_str(buf);
+}
+
+/*
+ * Append an integer to the end of the message.
+ */
+	static void
+ap_int(n)
+	int n;
+{
+	char buf[MAX_PRINT_INT];
+
+	sprintf(buf, "%d", n);
+	ap_str(buf);
+}
+
+/*
+ * Append a question mark to the end of the message.
+ */
+	static void
+ap_quest()
+{
+	ap_str("?");
+}
+
+/*
+ * Return the "current" byte offset in the file.
+ */
+	static POSITION
+curr_byte(where)
+	int where;
+{
+	POSITION pos;
+
+	pos = position(where);
+	while (pos == NULL_POSITION && where >= 0 && where < sc_height)
+		pos = position(++where);
+	if (pos == NULL_POSITION)
+		pos = ch_length();
+	return (pos);
+}
+
+/*
+ * Return the value of a prototype conditional.
+ * A prototype string may include conditionals which consist of a 
+ * question mark followed by a single letter.
+ * Here we decode that letter and return the appropriate boolean value.
+ */
+	static int
+cond(c, where)
+	char c;
+	int where;
+{
+	POSITION len;
+
+	switch (c)
+	{
+	case 'a':	/* Anything in the message yet? */
+		return (mp > message);
+	case 'b':	/* Current byte offset known? */
+		return (curr_byte(where) != NULL_POSITION);
+	case 'c':
+		return (hshift != 0);
+	case 'e':	/* At end of file? */
+		return (hit_eof);
+	case 'f':	/* Filename known? */
+		return (strcmp(get_filename(curr_ifile), "-") != 0);
+	case 'l':	/* Line number known? */
+	case 'd':	/* Same as l */
+		return (linenums);
+	case 'L':	/* Final line number known? */
+	case 'D':	/* Same as L */
+		return (linenums && ch_length() != NULL_POSITION);
+	case 'm':	/* More than one file? */
+		return (nifile() > 1);
+	case 'n':	/* First prompt in a new file? */
+		return (new_file);
+	case 'p':	/* Percent into file (bytes) known? */
+		return (curr_byte(where) != NULL_POSITION && 
+				ch_length() > 0);
+	case 'P':	/* Percent into file (lines) known? */
+		return (currline(where) != 0 &&
+				(len = ch_length()) > 0 &&
+				find_linenum(len) != 0);
+	case 's':	/* Size of file known? */
+	case 'B':
+		return (ch_length() != NULL_POSITION);
+	case 'x':	/* Is there a "next" file? */
+		return (next_ifile(curr_ifile) != NULL_IFILE);
+	}
+	return (0);
+}
+
+/*
+ * Decode a "percent" prototype character.
+ * A prototype string may include various "percent" escapes;
+ * that is, a percent sign followed by a single letter.
+ * Here we decode that letter and take the appropriate action,
+ * usually by appending something to the message being built.
+ */
+	static void
+protochar(c, where, iseditproto)
+	int c;
+	int where;
+	int iseditproto;
+{
+	POSITION pos;
+	POSITION len;
+	int n;
+	IFILE h;
+	char *s;
+	char *escs;
+
+	switch (c)
+	{
+	case 'b':	/* Current byte offset */
+		pos = curr_byte(where);
+		if (pos != NULL_POSITION)
+			ap_pos(pos);
+		else
+			ap_quest();
+		break;
+	case 'c':
+		ap_int(hshift);
+		break;
+	case 'd':	/* Current page number */
+		n = currline(where);
+		if (n > 0 && sc_height > 1)
+			ap_int(((n - 1) / (sc_height - 1)) + 1);
+		else
+			ap_quest();
+		break;
+	case 'D':	/* Last page number */
+		len = ch_length();
+		if (len == NULL_POSITION || len == ch_zero() ||
+		    (n = find_linenum(len)) <= 0)
+			ap_quest();
+		else
+			ap_int(((n - 1) / (sc_height - 1)) + 1);
+		break;
+#if EDITOR
+	case 'E':	/* Editor name */
+		ap_str(editor);
+		break;
+#endif
+	case 'f':	/* File name */
+		s = unquote_file(get_filename(curr_ifile));
+		/*
+		 * If we are expanding editproto then we escape metachars.
+		 * This allows us to run the editor on files with funny names.
+		 */
+		if (iseditproto && (escs = esc_metachars(s)) != NULL)
+		{
+			free(s);
+			s = escs;
+		}
+		ap_str(s);
+		free(s);
+		break;
+	case 'i':	/* Index into list of files */
+		ap_int(get_index(curr_ifile));
+		break;
+	case 'l':	/* Current line number */
+		n = currline(where);
+		if (n != 0)
+			ap_int(n);
+		else
+			ap_quest();
+		break;
+	case 'L':	/* Final line number */
+		len = ch_length();
+		if (len == NULL_POSITION || len == ch_zero() ||
+		    (n = find_linenum(len)) <= 0)
+			ap_quest();
+		else
+			ap_int(n-1);
+		break;
+	case 'm':	/* Number of files */
+		ap_int(nifile());
+		break;
+	case 'p':	/* Percent into file (bytes) */
+		pos = curr_byte(where);
+		len = ch_length();
+		if (pos != NULL_POSITION && len > 0)
+			ap_int(percentage(pos,len));
+		else
+			ap_quest();
+		break;
+	case 'P':	/* Percent into file (lines) */
+		pos = (POSITION) currline(where);
+		if (pos == 0 ||
+		    (len = ch_length()) == NULL_POSITION || len == ch_zero() ||
+		    (n = find_linenum(len)) <= 0)
+			ap_quest();
+		else
+			ap_int(percentage(pos, (POSITION)n));
+		break;
+	case 's':	/* Size of file */
+	case 'B':
+		len = ch_length();
+		if (len != NULL_POSITION)
+			ap_pos(len);
+		else
+			ap_quest();
+		break;
+	case 't':	/* Truncate trailing spaces in the message */
+		while (mp > message && mp[-1] == ' ')
+			mp--;
+		break;
+	case 'x':	/* Name of next file */
+		h = next_ifile(curr_ifile);
+		if (h != NULL_IFILE)
+		{
+			s = unquote_file(get_filename(h));
+			ap_str(s);
+			free(s);
+		} else
+			ap_quest();
+		break;
+	}
+}
+
+/*
+ * Skip a false conditional.
+ * When a false condition is found (either a false IF or the ELSE part 
+ * of a true IF), this routine scans the prototype string to decide
+ * where to resume parsing the string.
+ * We must keep track of nested IFs and skip them properly.
+ */
+	static char *
+skipcond(p)
+	register char *p;
+{
+	register int iflevel;
+
+	/*
+	 * We came in here after processing a ? or :,
+	 * so we start nested one level deep.
+	 */
+	iflevel = 1;
+
+	for (;;) switch (*++p)
+	{
+	case '?':
+		/*
+		 * Start of a nested IF.
+		 */
+		iflevel++;
+		break;
+	case ':':
+		/*
+		 * Else.
+		 * If this matches the IF we came in here with,
+		 * then we're done.
+		 */
+		if (iflevel == 1)
+			return (p);
+		break;
+	case '.':
+		/*
+		 * Endif.
+		 * If this matches the IF we came in here with,
+		 * then we're done.
+		 */
+		if (--iflevel == 0)
+			return (p);
+		break;
+	case '\\':
+		/*
+		 * Backslash escapes the next character.
+		 */
+		++p;
+		break;
+	case '\0':
+		/*
+		 * Whoops.  Hit end of string.
+		 * This is a malformed conditional, but just treat it
+		 * as if all active conditionals ends here.
+		 */
+		return (p-1);
+	}
+	/*NOTREACHED*/
+}
+
+/*
+ * Decode a char that represents a position on the screen.
+ */
+	static char *
+wherechar(p, wp)
+	char *p;
+	int *wp;
+{
+	switch (*p)
+	{
+	case 'b': case 'd': case 'l': case 'p': case 'P':
+		switch (*++p)
+		{
+		case 't':   *wp = TOP;			break;
+		case 'm':   *wp = MIDDLE;		break;
+		case 'b':   *wp = BOTTOM;		break;
+		case 'B':   *wp = BOTTOM_PLUS_ONE;	break;
+		case 'j':   *wp = adjsline(jump_sline);	break;
+		default:    *wp = TOP;  p--;		break;
+		}
+	}
+	return (p);
+}
+
+/*
+ * Construct a message based on a prototype string.
+ */
+	public char *
+pr_expand(proto, maxwidth)
+	char *proto;
+	int maxwidth;
+{
+	register char *p;
+	register int c;
+	int where;
+
+	mp = message;
+
+	if (*proto == '\0')
+		return ("");
+
+	for (p = proto;  *p != '\0';  p++)
+	{
+		switch (*p)
+		{
+		default:	/* Just put the character in the message */
+			ap_char(*p);
+			break;
+		case '\\':	/* Backslash escapes the next character */
+			p++;
+			ap_char(*p);
+			break;
+		case '?':	/* Conditional (IF) */
+			if ((c = *++p) == '\0')
+				--p;
+			else
+			{
+				where = 0;
+				p = wherechar(p, &where);
+				if (!cond(c, where))
+					p = skipcond(p);
+			}
+			break;
+		case ':':	/* ELSE */
+			p = skipcond(p);
+			break;
+		case '.':	/* ENDIF */
+			break;
+		case '%':	/* Percent escape */
+			if ((c = *++p) == '\0')
+				--p;
+			else
+			{
+				where = 0;
+				p = wherechar(p, &where);
+				protochar(c, where,
+#if EDITOR
+					(proto == editproto));
+#else
+					0);
+#endif
+
+			}
+			break;
+		}
+	}
+
+	new_file = 0;
+	if (mp == message)
+		return (NULL);
+	if (maxwidth > 0 && mp >= message + maxwidth)
+	{
+		/*
+		 * Message is too long.
+		 * Return just the final portion of it.
+		 */
+		return (mp - maxwidth);
+	}
+	return (message);
+}
+
+/*
+ * Return a message suitable for printing by the "=" command.
+ */
+	public char *
+eq_message()
+{
+	return (pr_expand(eqproto, 0));
+}
+
+/*
+ * Return a prompt.
+ * This depends on the prompt type (SHORT, MEDIUM, LONG), etc.
+ * If we can't come up with an appropriate prompt, return NULL
+ * and the caller will prompt with a colon.
+ */
+	public char *
+pr_string()
+{
+	if (ch_getflags() & CH_HELPFILE)
+		return (pr_expand(hproto, sc_width-so_s_width-so_e_width-2));
+	return (pr_expand(prproto[pr_type], sc_width-so_s_width-so_e_width-2));
+}