[hackers] [sbase] Add octal sequence support to tr(1) || FRIGN

[git]

commit eb57becb38526404c5bcea20bcb498a9ddb0a218
Author: FRIGN <d...@frign.de>
Date:   Sat Jan 24 22:43:46 2015 +0100

    Add octal sequence support to tr(1)

diff --git a/tr.1 b/tr.1
index 1f96dc5..29ea1f1 100644
--- a/tr.1
+++ b/tr.1
@@ -73,4 +73,4 @@ The
 .Nm
 utility is compliant with the
 .St -p1003.1-2008
-except from octal sequences and equivalence classes.
+specification except from equivalence classes.
diff --git a/tr.c b/tr.c
index cefb918..e2e6b71 100644
--- a/tr.c
+++ b/tr.c
@@ -73,7 +73,7 @@ rstrmatch(Rune *r, char *s, size_t n)
 static size_t
 resolveescapes(Rune *r, size_t len)
 {
-       size_t i, off, m;
+       size_t i, off, m, factor, q;
 
        for (i = 0; i < len - 1; i++) {
                if (r[i] != '\\')
@@ -89,7 +89,21 @@ resolveescapes(Rune *r, size_t len)
                case 'r':  r[i] = '\r'; off++; break;
                case 't':  r[i] = '\t'; off++; break;
                case 'v':  r[i] = '\v'; off++; break;
-               default:   continue;
+               case '\0':
+                       eprintf("tr: null escape sequence\n");
+               default:
+                       /* "\O[OO]" octal escape */
+                       for (m = i + 1; m < i + 1 + 3 && m < len; m++)
+                               if (r[m] < '0' || r[m] > '7')
+                                       break;
+                       if (m == i + 1)
+                               continue;
+                       off += m - i - 1;
+                       for (--m, q = 0, factor = 1; m > i; m--) {
+                               q += (r[m] - '0') * factor;
+                               factor *= 8;
+                       }
+                       r[i] = q;
                }
 
                for (m = i + 1; m <= len - off; m++)