blaze822_priv.h: use proper lc/uc

Mail headers may contain characters where the simple definition breaks,
which results in wrong formatting on output.

Fixes leahneukirchen#235.

blaze822_priv.h

@@ -12,9 +12,9 @@ struct message {
 
 #define isfws(c)  (((unsigned char)(c) == ' ' || (unsigned char)(c) == '\t' || (unsigned char)(c) == '\n' || (unsigned char)(c) == '\r'))
 
-// ASCII lowercase/uppercase without alpha check (wrong for "@[\]^_")
-#define lc(c) ((c) | 0x20)
-#define uc(c) ((c) & 0xdf)
+// 7bit-ASCII only lowercase/uppercase
+#define lc(c) (((unsigned)(c)-'A') < 26 ? ((c) | 0x20) : (c))
+#define uc(c) (((unsigned)(c)-'a') < 26 ? ((c) & 0xdf) : (c))
 
 // dirent type that can be a mail/dir (following symlinks)
 #if defined(DT_REG) && defined(DT_LNK) && defined(DT_UNKNOWN)

rfc2047.c

@@ -201,7 +201,8 @@ blaze822_decode_rfc2047(char *dst, char *src, size_t dlen, char *tgtenc)
 		if (ic == (iconv_t)-1)
 			goto nocode;
 
-		char enc = lc(*e++);
+		char enc = lc(*e);
+		e++;
 		if (*e++ != '?')
 			goto nocode;
 		char *start = e;

t/1100-mhdr.t

@@ -0,0 +1,26 @@
+#!/bin/sh -e
+cd ${0%/*}
+. ./lib.sh
+
+plan 9
+
+cat <<EOF >tmp
+Header: foo
+Header2: bar
+Header-Three: quux
+Header_Four: ding
+
+Body
+EOF
+
+check_same 'Header' 'mhdr -h Header ./tmp' 'echo foo'
+check_same 'Header2' 'mhdr -h Header2 ./tmp' 'echo bar'
+check_same 'Header-Three' 'mhdr -h Header-Three ./tmp' 'echo quux'
+check_same 'Header_Four' 'mhdr -h Header_Four ./tmp' 'echo ding'
+
+check_same 'header' 'mhdr -h header ./tmp' 'echo foo'
+check_same 'header2' 'mhdr -h header2 ./tmp' 'echo bar'
+check_same 'header-Three' 'mhdr -h header-Three ./tmp' 'echo quux'
+check_same 'header_Four' 'mhdr -h header_Four ./tmp' 'echo ding'
+
+check 'issue 235' 'mhdr ./tmp |grep -i header_four'