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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.
*
* The default commands are described by cmdtable.
* User-defined commands are read into usertable.
*/
#include "less.h"
#include "cmd.h"
/*
* Command table is ordered roughly according to expected
* frequency of use, so the common commands are near the beginning.
*/
static char cmdtable[] =
{
'\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,
'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,
CONTROL('['),'v',0, A_B_SCREEN,
'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,
CONTROL('['),'<',0, A_GOLINE,
'p',0, A_PERCENT,
'%',0, A_PERCENT,
'G',0, A_GOEND,
CONTROL('['),'>',0, A_GOEND,
'>',0, A_GOEND,
'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,
'/',0, A_F_SEARCH,
'?',0, A_B_SEARCH,
'n',0, A_AGAIN_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,
':','n',0, A_NEXT_FILE,
':','p',0, A_PREV_FILE,
'-',0, A_TOGGLE_OPTION,
'_',0, A_DISP_OPTION,
'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,
'Z','Z',0, A_QUIT
};
char *cmdendtable = cmdtable + sizeof(cmdtable);
static char usertable[MAX_USERCMD];
char *userendtable = usertable;
static char kbuf[MAX_CMDLEN+1];
static char *kp = kbuf;
/*
* Decode a command character and return the associated action.
*/
public int
cmd_decode(c)
int c;
{
register int action = A_INVALID;
/*
* Append the new command character to the command string in kbuf.
*/
*kp++ = c;
*kp = '\0';
#if USERFILE
/*
* Look first for any user-defined commands.
*/
action = cmd_search(usertable, userendtable);
#endif
/*
* If didn't find user-defined command,
* try the normal default commands.
*/
if (action == A_INVALID)
action = cmd_search(cmdtable, cmdendtable);
if (action != A_PREFIX)
/*
* This is not a prefix character.
*/
noprefix();
return (action);
}
/*
* Indicate that we're not in a prefix command
* by resetting the command buffer pointer.
*/
public void
noprefix()
{
kp = kbuf;
}
/*
* Search a command table for the current command string (in kbuf).
*/
static int
cmd_search(table, endtable)
char *table;
char *endtable;
{
register char *p;
register char *q;
for (p = table, q = kbuf; 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')
return (p[1]);
} 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 user's command.
*/
while (*p++ != '\0') ;
q = kbuf-1;
}
}
/*
* No match found in the entire command table.
*/
return (A_INVALID);
}
/*
* Initialize the user command table.
*/
public void
init_cmd()
{
#if USERFILE
char *filename;
char *homedir;
int f;
int n;
extern char *getenv();
/*
* Try to open "$HOME/.less"
* If we can't, return without doing anything.
*/
homedir = getenv("HOME");
if (homedir == NULL)
return;
filename = calloc(strlen(homedir)+7, sizeof(char));
if (filename == NULL)
return;
sprintf(filename, "%s/%s", homedir, ".less");
f = open(filename, 0);
free(filename);
if (f < 0)
return;
/*
* Read the file into the user table.
* {{ 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. }}
*/
n = read(f, (char *)usertable, MAX_USERCMD);
if (n < 3 || usertable[n-2] != '\0')
{
/*
* Several error cases are lumped together here:
* - Cannot read user file (n < 0).
* - User file is too short (a valid file must
* have at least 3 chars: one char command string,
* the terminating null byte, and the action byte).
* - The final entry in the user file is bad (it
* doesn't have a null byte in the proper place).
* Many other error cases are not caught, such as
* invalid format in any except the last entry,
* invalid action codes, command strings too long, etc.
*/
error("invalid user key file");
n = 0;
}
userendtable = usertable + n;
close(f);
#endif
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.