Clean up hex escape support.

1 files changed, 43 insertions, 21 deletions

diff --git a/libbb/process_escape_sequence.c b/libbb/process_escape_sequence.c
index 9b57ff99e..28b1e3697 100644
--- a/libbb/process_escape_sequence.c
+++ b/libbb/process_escape_sequence.c
@@ -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 {
-                        break;
+                d = (unsigned int)(*q - '0');
+#ifdef WANT_HEX_ESCAPES
+                if (d >= 10) {
+                        d = ((unsigned int)(_tolower(*q) - 'a')) + 10;
                 }
-                if (r <= UCHAR_MAX) {
-                        n = r;
-                        ++q;
-                        if (++num_digits < 3) {
-                                continue;
+#endif
+
+                if (d >= base) {
+#ifdef WANT_HEX_ESCAPES
+                        if ((base == 16) && (!--num_digits)) {
+/*                              return '\\'; */
+                                --q;
                         }
+#endif
+                        break;
                 }
-                break;
-        } while (1);
+
+                r = n * base + d;
+                if (r > UCHAR_MAX) {
+                        break;
+                }
+
+                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;
 }