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freebsd/contrib/less/decode.c
Xin LI e24497193b MFV: less v451.
2012-07-24 01:09:11 +00:00

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/*
* Copyright (C) 1984-2012 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, see the README file.
*/
/*
* 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.
*/
#include "less.h"
#include "cmd.h"
#include "lesskey.h"
extern int erase_char, erase2_char, kill_char;
extern int secure;
#define SK(k) \
SK_SPECIAL_KEY, (k), 6, 1, 1, 1
/*
* Command table is ordered roughly according to expected
* frequency of use, so the common commands are near the beginning.
*/
static unsigned char cmdtable[] =
{
'\r',0, A_F_LINE,
'\n',0, A_F_LINE,
'e',0, A_F_LINE,
'j',0, A_F_LINE,
SK(SK_DOWN_ARROW),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,
SK(SK_CONTROL_K),0, A_B_LINE,
CONTROL('P'),0, A_B_LINE,
SK(SK_UP_ARROW),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,
SK(SK_PAGE_DOWN),0, A_F_SCREEN,
'b',0, A_B_SCREEN,
CONTROL('B'),0, A_B_SCREEN,
ESC,'v',0, A_B_SCREEN,
SK(SK_PAGE_UP),0, A_B_SCREEN,
'z',0, A_F_WINDOW,
'w',0, A_B_WINDOW,
ESC,' ',0, A_FF_SCREEN,
'F',0, A_F_FOREVER,
ESC,'F',0, A_F_UNTIL_HILITE,
'R',0, A_FREPAINT,
'r',0, A_REPAINT,
CONTROL('R'),0, A_REPAINT,
CONTROL('L'),0, A_REPAINT,
ESC,'u',0, A_UNDO_SEARCH,
'g',0, A_GOLINE,
SK(SK_HOME),0, A_GOLINE,
'<',0, A_GOLINE,
ESC,'<',0, A_GOLINE,
'p',0, A_PERCENT,
'%',0, A_PERCENT,
ESC,'[',0, A_LSHIFT,
ESC,']',0, A_RSHIFT,
ESC,'(',0, A_LSHIFT,
ESC,')',0, A_RSHIFT,
SK(SK_RIGHT_ARROW),0, A_RSHIFT,
SK(SK_LEFT_ARROW),0, A_LSHIFT,
'{',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,
SK(SK_END),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_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,
'&',0, A_FILTER,
'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,
't',0, A_NEXT_TAG,
'T',0, A_PREV_TAG,
':','x',0, A_INDEX_FILE,
':','d',0, A_REMOVE_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,
SK(SK_F1),0, A_HELP,
'V',0, A_VERSION,
'q',0, A_QUIT,
'Q',0, A_QUIT,
':','q',0, A_QUIT,
':','Q',0, A_QUIT,
'Z','Z',0, A_QUIT
};
static unsigned char edittable[] =
{
'\t',0, EC_F_COMPLETE, /* TAB */
'\17',0, EC_B_COMPLETE, /* BACKTAB */
SK(SK_BACKTAB),0, EC_B_COMPLETE, /* BACKTAB */
ESC,'\t',0, EC_B_COMPLETE, /* ESC TAB */
CONTROL('L'),0, EC_EXPAND, /* CTRL-L */
CONTROL('V'),0, EC_LITERAL, /* BACKSLASH */
CONTROL('A'),0, EC_LITERAL, /* BACKSLASH */
ESC,'l',0, EC_RIGHT, /* ESC l */
SK(SK_RIGHT_ARROW),0, EC_RIGHT, /* RIGHTARROW */
ESC,'h',0, EC_LEFT, /* ESC h */
SK(SK_LEFT_ARROW),0, EC_LEFT, /* LEFTARROW */
ESC,'b',0, EC_W_LEFT, /* ESC b */
ESC,SK(SK_LEFT_ARROW),0, EC_W_LEFT, /* ESC LEFTARROW */
SK(SK_CTL_LEFT_ARROW),0, EC_W_LEFT, /* CTRL-LEFTARROW */
ESC,'w',0, EC_W_RIGHT, /* ESC w */
ESC,SK(SK_RIGHT_ARROW),0, EC_W_RIGHT, /* ESC RIGHTARROW */
SK(SK_CTL_RIGHT_ARROW),0, EC_W_RIGHT, /* CTRL-RIGHTARROW */
ESC,'i',0, EC_INSERT, /* ESC i */
SK(SK_INSERT),0, EC_INSERT, /* INSERT */
ESC,'x',0, EC_DELETE, /* ESC x */
SK(SK_DELETE),0, EC_DELETE, /* DELETE */
ESC,'X',0, EC_W_DELETE, /* ESC X */
ESC,SK(SK_DELETE),0, EC_W_DELETE, /* ESC DELETE */
SK(SK_CTL_DELETE),0, EC_W_DELETE, /* CTRL-DELETE */
SK(SK_CTL_BACKSPACE),0, EC_W_BACKSPACE, /* CTRL-BACKSPACE */
ESC,'\b',0, EC_W_BACKSPACE, /* ESC BACKSPACE */
ESC,'0',0, EC_HOME, /* ESC 0 */
SK(SK_HOME),0, EC_HOME, /* HOME */
ESC,'$',0, EC_END, /* ESC $ */
SK(SK_END),0, EC_END, /* END */
ESC,'k',0, EC_UP, /* ESC k */
SK(SK_UP_ARROW),0, EC_UP, /* UPARROW */
ESC,'j',0, EC_DOWN, /* ESC j */
SK(SK_DOWN_ARROW),0, EC_DOWN, /* DOWNARROW */
CONTROL('G'),0, EC_ABORT, /* CTRL-G */
};
/*
* Structure to support a list of command tables.
*/
struct tablelist
{
struct tablelist *t_next;
char *t_start;
char *t_end;
};
/*
* List of command tables and list of line-edit tables.
*/
static struct tablelist *list_fcmd_tables = NULL;
static struct tablelist *list_ecmd_tables = NULL;
static struct tablelist *list_var_tables = NULL;
static struct tablelist *list_sysvar_tables = NULL;
/*
* Expand special key abbreviations in a command table.
*/
static void
expand_special_keys(table, len)
char *table;
int len;
{
register char *fm;
register char *to;
register int a;
char *repl;
int klen;
for (fm = table; fm < table + len; )
{
/*
* Rewrite each command in the table with any
* special key abbreviations expanded.
*/
for (to = fm; *fm != '\0'; )
{
if (*fm != SK_SPECIAL_KEY)
{
*to++ = *fm++;
continue;
}
/*
* After SK_SPECIAL_KEY, next byte is the type
* of special key (one of the SK_* contants),
* and the byte after that is the number of bytes,
* N, reserved by the abbreviation (including the
* SK_SPECIAL_KEY and key type bytes).
* Replace all N bytes with the actual bytes
* output by the special key on this terminal.
*/
repl = special_key_str(fm[1]);
klen = fm[2] & 0377;
fm += klen;
if (repl == NULL || (int) strlen(repl) > klen)
repl = "\377";
while (*repl != '\0')
*to++ = *repl++;
}
*to++ = '\0';
/*
* Fill any unused bytes between end of command and
* the action byte with A_SKIP.
*/
while (to <= fm)
*to++ = A_SKIP;
fm++;
a = *fm++ & 0377;
if (a & A_EXTRA)
{
while (*fm++ != '\0')
continue;
}
}
}
/*
* Initialize the command lists.
*/
public void
init_cmds()
{
/*
* Add the default command tables.
*/
add_fcmd_table((char*)cmdtable, sizeof(cmdtable));
add_ecmd_table((char*)edittable, sizeof(edittable));
#if USERFILE
/*
* For backwards compatibility,
* try to add tables in the OLD system lesskey file.
*/
#ifdef BINDIR
add_hometable(NULL, BINDIR "/.sysless", 1);
#endif
/*
* Try to add the tables in the system lesskey file.
*/
add_hometable("LESSKEY_SYSTEM", LESSKEYFILE_SYS, 1);
/*
* Try to add the tables in the standard lesskey file "$HOME/.less".
*/
add_hometable("LESSKEY", LESSKEYFILE, 0);
#endif
}
/*
* Add a command table.
*/
static int
add_cmd_table(tlist, buf, len)
struct tablelist **tlist;
char *buf;
int len;
{
register struct tablelist *t;
if (len == 0)
return (0);
/*
* Allocate a tablelist structure, initialize it,
* and link it into the list of tables.
*/
if ((t = (struct tablelist *)
calloc(1, sizeof(struct tablelist))) == NULL)
{
return (-1);
}
expand_special_keys(buf, len);
t->t_start = buf;
t->t_end = buf + len;
t->t_next = *tlist;
*tlist = t;
return (0);
}
/*
* Add a command table.
*/
public void
add_fcmd_table(buf, len)
char *buf;
int len;
{
if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
error("Warning: some commands disabled", NULL_PARG);
}
/*
* Add an editing command table.
*/
public void
add_ecmd_table(buf, len)
char *buf;
int len;
{
if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
error("Warning: some edit commands disabled", NULL_PARG);
}
/*
* Add an environment variable table.
*/
static void
add_var_table(tlist, buf, len)
struct tablelist **tlist;
char *buf;
int len;
{
if (add_cmd_table(tlist, buf, len) < 0)
error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
}
/*
* Search a single command table for the 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;
*sp = NULL;
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;
while (a == A_SKIP)
a = *++p & 0377;
if (a == A_END_LIST)
{
/*
* We get here only if the original
* cmd string passed in was empty ("").
* I don't think that can happen,
* but just in case ...
*/
return (A_UINVALID);
}
/*
* Check for an "extra" string.
*/
if (a & A_EXTRA)
{
*sp = ++p;
a &= ~A_EXTRA;
}
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.
*/
if (*p == '\0' && p[1] == A_END_LIST)
{
/*
* A_END_LIST is a special marker that tells
* us to abort the cmd search.
*/
return (A_UINVALID);
}
while (*p++ != '\0')
continue;
while (*p == A_SKIP)
p++;
if (*p & A_EXTRA)
while (*++p != '\0')
continue;
q = cmd-1;
}
}
/*
* No match found in the entire command table.
*/
return (A_INVALID);
}
/*
* Decode a command character and return the associated action.
* The "extra" string, if any, is returned in sp.
*/
static int
cmd_decode(tlist, cmd, sp)
struct tablelist *tlist;
char *cmd;
char **sp;
{
register struct tablelist *t;
register int action = A_INVALID;
/*
* Search thru all the command tables.
* Stop when we find an action which is not A_INVALID.
*/
for (t = tlist; t != NULL; t = t->t_next)
{
action = cmd_search(cmd, t->t_start, t->t_end, sp);
if (action != A_INVALID)
break;
}
if (action == A_UINVALID)
action = A_INVALID;
return (action);
}
/*
* Decode a command from the cmdtables list.
*/
public int
fcmd_decode(cmd, sp)
char *cmd;
char **sp;
{
return (cmd_decode(list_fcmd_tables, cmd, sp));
}
/*
* Decode a command from the edittables list.
*/
public int
ecmd_decode(cmd, sp)
char *cmd;
char **sp;
{
return (cmd_decode(list_ecmd_tables, cmd, sp));
}
/*
* Get the value of an environment variable.
* Looks first in the lesskey file, then in the real environment.
*/
public char *
lgetenv(var)
char *var;
{
int a;
char *s;
a = cmd_decode(list_var_tables, var, &s);
if (a == EV_OK)
return (s);
s = getenv(var);
if (s != NULL && *s != '\0')
return (s);
a = cmd_decode(list_sysvar_tables, var, &s);
if (a == EV_OK)
return (s);
return (NULL);
}
#if USERFILE
/*
* Get an "integer" from a lesskey file.
* Integers are stored in a funny format:
* two bytes, low order first, in radix KRADIX.
*/
static int
gint(sp)
char **sp;
{
int n;
n = *(*sp)++;
n += *(*sp)++ * KRADIX;
return (n);
}
/*
* Process an old (pre-v241) lesskey file.
*/
static int
old_lesskey(buf, len)
char *buf;
int len;
{
/*
* Old-style lesskey file.
* The file must end with either
* ...,cmd,0,action
* or ...,cmd,0,action|A_EXTRA,string,0
* So the last byte or the second to last byte must be zero.
*/
if (buf[len-1] != '\0' && buf[len-2] != '\0')
return (-1);
add_fcmd_table(buf, len);
return (0);
}
/*
* Process a new (post-v241) lesskey file.
*/
static int
new_lesskey(buf, len, sysvar)
char *buf;
int len;
int sysvar;
{
char *p;
register int c;
register int n;
/*
* New-style lesskey file.
* Extract the pieces.
*/
if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
buf[len-2] != C1_END_LESSKEY_MAGIC ||
buf[len-1] != C2_END_LESSKEY_MAGIC)
return (-1);
p = buf + 4;
for (;;)
{
c = *p++;
switch (c)
{
case CMD_SECTION:
n = gint(&p);
add_fcmd_table(p, n);
p += n;
break;
case EDIT_SECTION:
n = gint(&p);
add_ecmd_table(p, n);
p += n;
break;
case VAR_SECTION:
n = gint(&p);
add_var_table((sysvar) ?
&list_sysvar_tables : &list_var_tables, p, n);
p += n;
break;
case END_SECTION:
return (0);
default:
/*
* Unrecognized section type.
*/
return (-1);
}
}
}
/*
* Set up a user command table, based on a "lesskey" file.
*/
public int
lesskey(filename, sysvar)
char *filename;
int sysvar;
{
register char *buf;
register POSITION len;
register long n;
register int f;
if (secure)
return (1);
/*
* Try to open the lesskey file.
*/
filename = shell_unquote(filename);
f = open(filename, OPEN_READ);
free(filename);
if (f < 0)
return (1);
/*
* Read the file into a buffer.
* 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 ((buf = (char *) calloc((int)len, sizeof(char))) == NULL)
{
close(f);
return (-1);
}
if (lseek(f, (off_t)0, SEEK_SET) == BAD_LSEEK)
{
free(buf);
close(f);
return (-1);
}
n = read(f, buf, (unsigned int) len);
close(f);
if (n != len)
{
free(buf);
return (-1);
}
/*
* Figure out if this is an old-style (before version 241)
* or new-style lesskey file format.
*/
if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
return (old_lesskey(buf, (int)len));
return (new_lesskey(buf, (int)len, sysvar));
}
/*
* Add the standard lesskey file "$HOME/.less"
*/
public void
add_hometable(envname, def_filename, sysvar)
char *envname;
char *def_filename;
int sysvar;
{
char *filename;
PARG parg;
if (envname != NULL && (filename = lgetenv(envname)) != NULL)
filename = save(filename);
else if (sysvar)
filename = save(def_filename);
else
filename = homefile(def_filename);
if (filename == NULL)
return;
if (lesskey(filename, sysvar) < 0)
{
parg.p_string = filename;
error("Cannot use lesskey file \"%s\"", &parg);
}
free(filename);
}
#endif
/*
* See if a char is a special line-editing command.
*/
public int
editchar(c, flags)
int c;
int flags;
{
int action;
int nch;
char *s;
char usercmd[MAX_CMDLEN+1];
/*
* An editing character could actually be a sequence of characters;
* for example, an escape sequence sent by pressing the uparrow key.
* To match the editing string, we use the command decoder
* but give it the edit-commands command table
* This table is constructed to match the user's keyboard.
*/
if (c == erase_char || c == erase2_char)
return (EC_BACKSPACE);
if (c == kill_char)
return (EC_LINEKILL);
/*
* Collect characters in a buffer.
* Start with the one we have, and get more if we need them.
*/
nch = 0;
do {
if (nch > 0)
c = getcc();
usercmd[nch] = c;
usercmd[nch+1] = '\0';
nch++;
action = ecmd_decode(usercmd, &s);
} while (action == A_PREFIX);
if (flags & EC_NORIGHTLEFT)
{
switch (action)
{
case EC_RIGHT:
case EC_LEFT:
action = A_INVALID;
break;
}
}
#if CMD_HISTORY
if (flags & EC_NOHISTORY)
{
/*
* The caller says there is no history list.
* Reject any history-manipulation action.
*/
switch (action)
{
case EC_UP:
case EC_DOWN:
action = A_INVALID;
break;
}
}
#endif
#if TAB_COMPLETE_FILENAME
if (flags & EC_NOCOMPLETE)
{
/*
* The caller says we don't want any filename completion cmds.
* Reject them.
*/
switch (action)
{
case EC_F_COMPLETE:
case EC_B_COMPLETE:
case EC_EXPAND:
action = A_INVALID;
break;
}
}
#endif
if ((flags & EC_PEEK) || action == A_INVALID)
{
/*
* We're just peeking, or we didn't understand the command.
* Unget all the characters we read in the loop above.
* This does NOT include the original character that was
* passed in as a parameter.
*/
while (nch > 1)
{
ungetcc(usercmd[--nch]);
}
} else
{
if (s != NULL)
ungetsc(s);
}
return action;
}
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