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gno/bin/less/decode.c

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/*
* Routines to decode user commands.
*
* This is all table driven.
* A command table is a sequence of command descriptors.
* Each command descriptor is a sequence of bytes with the following format:
* <c1><c2>...<cN><0><action>
* The characters c1,c2,...,cN are the command string; that is,
* the characters which the user must type.
* It is terminated by a null <0> byte.
* The byte after the null byte is the action code associated
* with the command string.
* If an action byte is OR-ed with A_EXTRA, this indicates
* that the option byte is followed by an extra string.
*
* There may be many command tables.
* The first (default) table is built-in.
* Other tables are read in from "lesskey" files.
* All the tables are linked together and are searched in order.
*/
#pragma noroot
#include "less.h"
#include "cmd.h"
#if __MSDOS__
#include <io.h>
#include <stdlib.h>
#endif
#ifdef _ORCAC_
#include <fcntl.h>
segment "LoadSegONE";
#endif
/*
* Command table is ordered roughly according to expected
* frequency of use, so the common commands are near the beginning.
*/
static char cmdtable[] =
{
#if __MSDOS__
/*
* PC function keys.
* Note that '\0' is converted to '\200' on input.
*/
'\200','\120',0, A_F_LINE, /* down arrow */
'\200','\121',0, A_F_SCREEN, /* page down */
'\200','\110',0, A_B_LINE, /* up arrow */
'\200','\111',0, A_B_SCREEN, /* page up */
'\200','\107',0, A_GOLINE, /* home */
'\200','\117',0, A_GOEND, /* end */
'\200','\073',0, A_HELP, /* F1 */
'\200','\104',0, A_MODIFY_WINDOW, /* F10 */
'\200','\103',0, A_MODIFY_COLOURS, /* F9 */
#endif
'\r',0, A_F_LINE,
'\n',0, A_F_LINE,
'e',0, A_F_LINE,
'j',0, A_F_LINE,
CONTROL('E'),0, A_F_LINE,
CONTROL('N'),0, A_F_LINE,
'k',0, A_B_LINE,
'y',0, A_B_LINE,
CONTROL('Y'),0, A_B_LINE,
CONTROL('K'),0, A_B_LINE,
CONTROL('P'),0, A_B_LINE,
'J',0, A_FF_LINE,
'K',0, A_BF_LINE,
'Y',0, A_BF_LINE,
'd',0, A_F_SCROLL,
CONTROL('D'),0, A_F_SCROLL,
'u',0, A_B_SCROLL,
CONTROL('U'),0, A_B_SCROLL,
' ',0, A_F_SCREEN,
'f',0, A_F_SCREEN,
CONTROL('F'),0, A_F_SCREEN,
CONTROL('V'),0, A_F_SCREEN,
'b',0, A_B_SCREEN,
CONTROL('B'),0, A_B_SCREEN,
ESC,'v',0, A_B_SCREEN,
'z',0, A_F_WINDOW,
'w',0, A_B_WINDOW,
'F',0, A_F_FOREVER,
'R',0, A_FREPAINT,
'r',0, A_REPAINT,
CONTROL('R'),0, A_REPAINT,
CONTROL('L'),0, A_REPAINT,
'g',0, A_GOLINE,
'<',0, A_GOLINE,
ESC,'<',0, A_GOLINE,
'p',0, A_PERCENT,
'%',0, A_PERCENT,
'{',0, A_F_BRACKET|A_EXTRA, '{','}',0,
'}',0, A_B_BRACKET|A_EXTRA, '{','}',0,
'(',0, A_F_BRACKET|A_EXTRA, '(',')',0,
')',0, A_B_BRACKET|A_EXTRA, '(',')',0,
'[',0, A_F_BRACKET|A_EXTRA, '[',']',0,
']',0, A_B_BRACKET|A_EXTRA, '[',']',0,
ESC,CONTROL('F'),0, A_F_BRACKET,
ESC,CONTROL('B'),0, A_B_BRACKET,
'G',0, A_GOEND,
ESC,'>',0, A_GOEND,
'>',0, A_GOEND,
'P',0, A_GOPOS,
'0',0, A_DIGIT,
'1',0, A_DIGIT,
'2',0, A_DIGIT,
'3',0, A_DIGIT,
'4',0, A_DIGIT,
'5',0, A_DIGIT,
'6',0, A_DIGIT,
'7',0, A_DIGIT,
'8',0, A_DIGIT,
'9',0, A_DIGIT,
'=',0, A_STAT,
CONTROL('G'),0, A_STAT,
':','f',0, A_STAT,
'/',0, A_F_SEARCH,
'?',0, A_B_SEARCH,
ESC,'/',0, A_F_SEARCH|A_EXTRA, '*',0,
ESC,'?',0, A_B_SEARCH|A_EXTRA, '*',0,
'n',0, A_AGAIN_SEARCH,
ESC,'n',0, A_T_AGAIN_SEARCH,
'N',0, A_REVERSE_SEARCH,
ESC,'N',0, A_T_REVERSE_SEARCH,
'm',0, A_SETMARK,
'\'',0, A_GOMARK,
CONTROL('X'),CONTROL('X'),0, A_GOMARK,
'E',0, A_EXAMINE,
':','e',0, A_EXAMINE,
CONTROL('X'),CONTROL('V'),0, A_EXAMINE,
':','n',0, A_NEXT_FILE,
':','p',0, A_PREV_FILE,
':','x',0, A_INDEX_FILE,
'-',0, A_OPT_TOGGLE,
':','t',0, A_OPT_TOGGLE|A_EXTRA, 't',0,
's',0, A_OPT_TOGGLE|A_EXTRA, 'o',0,
'_',0, A_DISP_OPTION,
'|',0, A_PIPE,
'v',0, A_VISUAL,
'!',0, A_SHELL,
'+',0, A_FIRSTCMD,
'H',0, A_HELP,
'h',0, A_HELP,
'V',0, A_VERSION,
'q',0, A_QUIT,
':','q',0, A_QUIT,
':','Q',0, A_QUIT,
'Z','Z',0, A_QUIT,
ESC,ESC,0, A_QUIT,
};
/*
* Structure to support a list of command tables.
*/
struct tablelist
{
struct tablelist *t_next;
char *t_start;
char *t_end;
};
/*
* Structure for the default command table.
*/
static struct tablelist deftable =
{ NULL, cmdtable, cmdtable+sizeof(cmdtable) };
/*
* List of tables; initially contains only the default table.
*/
static struct tablelist *tables = &deftable;
static int cmd_search(char *cmd, char *table, char *endtable, char **sp);
extern int erase_char, kill_char;
/*
* Decode a command character and return the associated action.
* The "extra" string, if any, is returned in sp.
*/
public int
cmd_decode(cmd, sp)
char *cmd;
char **sp;
{
register struct tablelist *t;
register int action;
/*
* Search thru all the command tables.
* Stop when we find an action which is not A_INVALID.
*/
for (t = tables; t != NULL; t = t->t_next)
{
action = cmd_search(cmd, t->t_start, t->t_end, sp);
if (action != A_INVALID)
break;
}
return (action);
}
/*
* Search a command table for the current command string (in cmd).
*/
static int
cmd_search(cmd, table, endtable, sp)
char *cmd;
char *table;
char *endtable;
char **sp;
{
register char *p;
register char *q;
register int a;
for (p = table, q = cmd; p < endtable; p++, q++)
{
if (*p == *q)
{
/*
* Current characters match.
* If we're at the end of the string, we've found it.
* Return the action code, which is the character
* after the null at the end of the string
* in the command table.
*/
if (*p == '\0')
{
a = *++p & 0377;
/*
* Check for an "extra" string.
*/
if (a & A_EXTRA)
{
*sp = ++p;
a &= ~A_EXTRA;
} else
*sp = NULL;
return (a);
}
} else if (*q == '\0')
{
/*
* Hit the end of the user's command,
* but not the end of the string in the command table.
* The user's command is incomplete.
*/
return (A_PREFIX);
} else
{
/*
* Not a match.
* Skip ahead to the next command in the
* command table, and reset the pointer
* to the beginning of the user's command.
*/
while (*p++ != '\0') ;
if (*p & A_EXTRA)
while (*++p != '\0') ;
q = cmd-1;
}
}
/*
* No match found in the entire command table.
*/
return (A_INVALID);
}
#if USERFILE
/*
* Set up a user command table, based on a "lesskey" file.
*/
public int
add_cmdtable(filename)
char *filename;
{
register struct tablelist *t;
register POSITION len;
register long n;
register int f;
/*
* Try to open the lesskey file.
* If we can't, return an error.
*/
f = open(filename, O_RDONLY);
if (f < 0)
return (-1);
/*
* Read the file into the user table.
* We first figure out the size of the file and allocate space for it.
* {{ Minimal error checking is done here.
* A garbage .less file will produce strange results.
* To avoid a large amount of error checking code here, we
* rely on the lesskey program to generate a good .less file. }}
*/
len = filesize(f);
if (len == NULL_POSITION || len < 3)
{
/*
* Bad file (valid file must have at least 3 chars).
*/
close(f);
return (-1);
}
if ((t = (struct tablelist *)
calloc(1, sizeof(struct tablelist))) == NULL)
{
close(f);
return (-1);
}
if ((t->t_start = (char *) calloc(len, sizeof(char))) == NULL)
{
free((char *)t);
close(f);
return (-1);
}
if (lseek(f, (offset_t)0, 0) == BAD_LSEEK)
{
free(t->t_start);
free((char *)t);
close(f);
return (-1);
}
n = read(f, t->t_start, (size_t) len);
close(f);
/*
* In a valid lesskey file, the last byte or
* the second to the last byte must be zero.
*/
if (n != len || (t->t_start[n-1] != '\0' && t->t_start[n-2] != '\0'))
{
free(t->t_start);
free((char *)t);
return (-1);
}
t->t_end = t->t_start + n;
/*
* Link it into the list of tables.
*/
t->t_next = tables;
tables = t;
return (0);
}
/*
* Try to add the lesskey file "$HOME/.less"
*/
public void
add_hometable(void)
{
char *filename;
#if __MSDOS__
filename = homefile("_less");
#else
filename = homefile("lessrc");
#endif
if (filename == NULL)
return;
/*
* Ignore errors.
*/
(void) add_cmdtable(filename);
free(filename);
}
#endif
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