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Clean up hex escape support.

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This commit is contained in:
Manuel Novoa III 2004-07-29 23:15:16 +00:00
parent 27645b4345
commit 413db4d583
1 changed files with 43 additions and 21 deletions
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64
libbb/process_escape_sequence.c
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@ -22,48 +22,69 @@
*
*/
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include <ctype.h>
#include "libbb.h"
#define isodigit(c) ((c) >= '0' && (c) <= '7')
#define hextobin(c) ((c)>='a'&&(c)<='f' ? (c)-'a'+10 : (c)>='A'&&(c)<='F' ? (c)-'A'+10 : (c)-'0')
#define octtobin(c) ((c) - '0')
#define WANT_HEX_ESCAPES 1
/* Usual "this only works for ascii compatible encodings" disclaimer. */
#undef _tolower
#define _tolower(X) ((X)|((char) 0x20))
char bb_process_escape_sequence(const char **ptr)
{
const char *p, *q;
unsigned int num_digits, r, n, hexescape;
static const char charmap[] = {
'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', 0,
'\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
n = r = hexescape = num_digits = 0;
const char *p;
const char *q;
unsigned int num_digits;
unsigned int r;
unsigned int n;
unsigned int d;
unsigned int base;
num_digits = n = 0;
base = 8;
q = *ptr;
#ifdef WANT_HEX_ESCAPES
if (*q == 'x') {
hexescape++;
++q;
base = 16;
++num_digits;
}
#endif
do {
if (hexescape && isxdigit(*q)) {
r = n * 16 + hextobin(*q);
} else if (isodigit(*q)) {
r = n * 8 + octtobin(*q);
} else {
d = (unsigned int)(*q - '0');
#ifdef WANT_HEX_ESCAPES
if (d >= 10) {
d = ((unsigned int)(_tolower(*q) - 'a')) + 10;
}
#endif
if (d >= base) {
#ifdef WANT_HEX_ESCAPES
if ((base == 16) && (!--num_digits)) {
/* return '\\'; */
--q;
}
#endif
break;
}
if (r <= UCHAR_MAX) {
n = r;
++q;
if (++num_digits < 3) {
continue;
}
r = n * base + d;
if (r > UCHAR_MAX) {
break;
}
break;
} while (1);
n = r;
++q;
} while (++num_digits < 3);
if (num_digits == 0) { /* mnemonic escape sequence? */
p = charmap;
@ -77,6 +98,7 @@ char bb_process_escape_sequence(const char **ptr)
}
*ptr = q;
return (char) n;
}