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/*-
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Jordan K. Hubbard
* 29 August 1998
*
* Routine for doing backslash elimination.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include <string.h>
#include "bootstrap.h"
#define DIGIT(x) (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
/*
* backslash: Return malloc'd copy of str with all standard "backslash
* processing" done on it. Original can be free'd if desired.
*/
char *
backslash(char *str)
{
/*
* Remove backslashes from the strings. Turn \040 etc. into a single
* character (we allow eight bit values). Currently NUL is not
* allowed.
*
* Turn "\n" and "\t" into '\n' and '\t' characters. Etc.
*
*/
char *new_str;
int seenbs = 0;
int i = 0;
if ((new_str = strdup(str)) == NULL)
return NULL;
while (*str) {
if (seenbs) {
seenbs = 0;
switch (*str) {
case '\\':
new_str[i++] = '\\';
str++;
break;
/* preserve backslashed quotes, dollar signs */
case '\'':
case '"':
case '$':
new_str[i++] = '\\';
new_str[i++] = *str++;
break;
case 'b':
new_str[i++] = '\b';
str++;
break;
case 'f':
new_str[i++] = '\f';
str++;
break;
case 'r':
new_str[i++] = '\r';
str++;
break;
case 'n':
new_str[i++] = '\n';
str++;
break;
case 's':
new_str[i++] = ' ';
str++;
break;
case 't':
new_str[i++] = '\t';
str++;
break;
case 'v':
new_str[i++] = '\13';
str++;
break;
case 'z':
str++;
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9': {
char val;
/* Three digit octal constant? */
if (*str >= '0' && *str <= '3' &&
*(str + 1) >= '0' && *(str + 1) <= '7' &&
*(str + 2) >= '0' && *(str + 2) <= '7') {
val = (DIGIT(*str) << 6) + (DIGIT(*(str + 1)) << 3) +
DIGIT(*(str + 2));
/* Allow null value if user really wants to shoot
at feet, but beware! */
new_str[i++] = val;
str += 3;
break;
}
/* One or two digit hex constant?
* If two are there they will both be taken.
* Use \z to split them up if this is not wanted.
*/
if (*str == '0' &&
(*(str + 1) == 'x' || *(str + 1) == 'X') &&
isxdigit(*(str + 2))) {
val = DIGIT(*(str + 2));
if (isxdigit(*(str + 3))) {
val = (val << 4) + DIGIT(*(str + 3));
str += 4;
}
else
str += 3;
/* Yep, allow null value here too */
new_str[i++] = val;
break;
}
}
break;
default:
new_str[i++] = *str++;
break;
}
}
else {
if (*str == '\\') {
seenbs = 1;
str++;
}
else
new_str[i++] = *str++;
}
}
if (seenbs) {
/*
* The final character was a '\'. Put it in as a single backslash.
*/
new_str[i++] = '\\';
}
new_str[i] = '\0';
return new_str;
}
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