procps/proc/escape.c
Jim Warner ba9560ff02 library: reduce overhead for another 'escape' function
The preceding commit made that 'esc_all' function more
efficient by using direct pointer manipulation instead
of an indexed string reference approach within a loop.

This commit applies the same approach to the 'esc_ctl'
function. Now we'll save 12 more iterated instructions
while decreasing the function's code size by 43 bytes.

Signed-off-by: Jim Warner <james.warner@comcast.net>
2021-01-21 17:30:24 +11:00

143 lines
4.6 KiB
C

/*
* escape.c - printing handling
* Copyright 1998-2002 by Albert Cahalan
* Copyright 2020 Jim Warner <james.warner@comcast.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <langinfo.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include "escape.h"
#include "readproc.h"
#define SECURE_ESCAPE_ARGS(dst, bytes) do { \
if ((bytes) <= 0) return 0; \
*(dst) = '\0'; \
if ((bytes) >= INT_MAX) return 0; \
} while (0)
static const char UTF_tab[] = {
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x00 - 0x0F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x10 - 0x1F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x20 - 0x2F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x30 - 0x3F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x40 - 0x4F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x50 - 0x5F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x60 - 0x6F
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0x70 - 0x7F
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, // 0x80 - 0x8F
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, // 0x90 - 0x9F
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, // 0xA0 - 0xAF
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, // 0xB0 - 0xBF
-1,-1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 0xC0 - 0xCF
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // 0xD0 - 0xDF
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // 0xE0 - 0xEF
4, 4, 4, 4, 4,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, // 0xF0 - 0xFF
};
static const unsigned char ESC_tab[] = {
"@..............................." // 0x00 - 0x1F
"||||||||||||||||||||||||||||||||" // 0x20 - 0x3F
"||||||||||||||||||||||||||||||||" // 0x40 - 0x5f
"|||||||||||||||||||||||||||||||." // 0x60 - 0x7F
"????????????????????????????????" // 0x80 - 0x9F
"????????????????????????????????" // 0xA0 - 0xBF
"????????????????????????????????" // 0xC0 - 0xDF
"????????????????????????????????" // 0xE0 - 0xFF
};
static inline void esc_all (unsigned char *str) {
unsigned char c;
// if bad locale/corrupt str, replace non-printing stuff
while (*str) {
if ((c = ESC_tab[*str]) != '|')
*str = c;
++str;
}
}
static inline void esc_ctl (unsigned char *str, int len) {
int i, n;
for (i = 0; i < len; ) {
// even with a proper locale, strings might be corrupt
if ((n = UTF_tab[*str]) < 0 || i + n > len) {
esc_all(str);
return;
}
// and eliminate those non-printing control characters
if (*str < 0x20 || *str == 0x7f)
*str = '?';
str += n;
i += n;
}
}
int escape_str (unsigned char *dst, const unsigned char *src, int bufsize) {
static int utf_sw = 0;
int n;
if (utf_sw == 0) {
char *enc = nl_langinfo(CODESET);
utf_sw = enc && strcasecmp(enc, "UTF-8") == 0 ? 1 : -1;
}
SECURE_ESCAPE_ARGS(dst, bufsize);
n = snprintf(dst, bufsize, "%s", src);
if (n < 0) {
*dst = '\0';
return 0;
}
if (n >= bufsize) n = bufsize-1;
if (utf_sw < 0)
esc_all(dst);
else
esc_ctl(dst, n);
return n;
}
int escape_command (unsigned char *outbuf, const proc_t *pp, int bytes, unsigned flags) {
int overhead = 0;
int end = 0;
if (flags & ESC_BRACKETS)
overhead += 2;
if (flags & ESC_DEFUNCT) {
if (pp->state == 'Z') overhead += 10; // chars in " <defunct>"
else flags &= ~ESC_DEFUNCT;
}
if (overhead + 1 >= bytes) {
// if no room for even one byte of the command name
outbuf[0] = '\0';
return 0;
}
if (flags & ESC_BRACKETS)
outbuf[end++] = '[';
end += escape_str(outbuf+end, pp->cmd, bytes-overhead);
// we want "[foo] <defunct>", not "[foo <defunct>]"
if (flags & ESC_BRACKETS)
outbuf[end++] = ']';
if (flags & ESC_DEFUNCT) {
memcpy(outbuf+end, " <defunct>", 10);
end += 10;
}
outbuf[end] = '\0';
return end; // bytes, not including the NUL
}