4.4BSD/usr/src/contrib/mh-6.8/miscellany/less-177/prompt.c
/*
* 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 sc_height;
extern int jump_sline;
extern IFILE curr_ifile;
#if EDITOR
extern char *editor;
#endif
/*
* Prototypes for the three flavors of prompts.
* These strings are expanded by pr_expand().
*/
static char s_proto[] =
"?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\\: %x..%t";
static char m_proto[] =
"?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t";
static char M_proto[] =
"?f%f .?n?m(file %i of %m) ..?ltline %lt?L/%L. :byte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t";
static char e_proto[] =
"?f%f .?m(file %i of %m) .?ltline %lt?L/%L. .byte %bB?s/%s. ?e(END) :?pB%pB\\%..%t";
public char *prproto[3];
public char *eqproto = e_proto;
static char message[250];
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);
}
/*
* Set the message pointer to the end of the message string.
*/
static void
setmp()
{
while (*mp != '\0')
mp++;
}
/*
* Append a POSITION (as a decimal integer) to the end of the message.
*/
static void
ap_pos(pos)
POSITION pos;
{
sprintf(mp, "%ld", (long)pos);
setmp();
}
/*
* Append an integer to the end of the message.
*/
static void
ap_int(n)
int n;
{
sprintf(mp, "%d", n);
setmp();
}
/*
* Append a string to the end of the message.
*/
static void
ap_str(s)
char *s;
{
strtcpy(mp, s, (unsigned int)(&message[sizeof(message)] - mp));
setmp();
}
/*
* Append a question mark to the end of the message.
*/
static void
ap_quest()
{
*mp++ = '?';
}
/*
* 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;
{
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 'e': /* At end of file? */
return (hit_eof);
case 'f': /* Filename known? */
return (strcmp(get_filename(curr_ifile), "-") != 0);
case 'l': /* Line number known? */
return (linenums);
case 'L': /* Final line number known? */
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 known? */
return (curr_byte(where) != NULL_POSITION &&
ch_length() > 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)
int c;
int where;
{
POSITION pos;
POSITION len;
int n;
IFILE h;
switch (c)
{
case 'b': /* Current byte offset */
pos = curr_byte(where);
if (pos != NULL_POSITION)
ap_pos(pos);
else
ap_quest();
break;
#if EDITOR
case 'E': /* Editor name */
ap_str(editor);
break;
#endif
case 'f': /* File name */
ap_str(get_filename(curr_ifile));
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 */
pos = curr_byte(where);
len = ch_length();
if (pos != NULL_POSITION && len > 0)
/*
* {{ This calculation may overflow! }}
*/
ap_int((int)(100*pos / len));
else
ap_quest();
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)
ap_str(get_filename(h));
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*/
}
static char *
wherechar(p, wp)
char *p;
int *wp;
{
switch (*p)
{
case 'b': case 'l': 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 */
*mp++ = *p;
break;
case '\\': /* Backslash escapes the next character */
p++;
*mp++ = *p;
break;
case '?': /* Conditional (IF) */
if ((c = *++p) == '\0')
--p;
else
{
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
{
p = wherechar(p, &where);
protochar(c, where);
}
break;
}
}
new_file = 0;
if (mp == message)
return (NULL);
*mp = '\0';
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()
{
return (pr_expand(prproto[pr_type], sc_width-so_s_width-so_e_width-2));
}