Fixed bug #896
authorSam Lantinga <slouken@libsdl.org>
Fri, 11 Dec 2009 08:03:43 +0000
changeset 3539 f2846bf19360
parent 3538 a1896642a47e
child 3540 3ad09fdbfcb0
Fixed bug #896 John Popplewell 2009-12-08 23:05:50 PST Originally reported by AKFoerster on the mailing list. Error decoding UTF8 Russian text to UTF-16LE on Windows, but specifically on platforms without iconv support (the default on Windows). Valid UTF8 characters are flagged as being overlong and then substituted by the UNKNOWN_UNICODE character. After studying the testiconv.c example program, reading the RFCs and putting some printf statements in SDL_iconv.c the problem is in a test for 'Maximum overlong sequences', specifically 4.2.1, which is carried out by the following code: } else if ( p[0] >= 0xC0 ) { if ( (p[0] & 0xE0) != 0xC0 ) { /* Skip illegal sequences return SDL_ICONV_EILSEQ; */ ch = UNKNOWN_UNICODE; } else { if ( (p[0] & 0xCE) == 0xC0 ) { <<<<<<<< here overlong = SDL_TRUE; } ch = (Uint32)(p[0] & 0x1F); left = 1; } } else { Here is the 2-byte encoding of a character in range 00000080 - 000007FF 110xxxxx 10xxxxxx The line in question is supposed to be checking for an overlong sequence which would be less than 11000001 10111111 which should be represented as a single byte. BUT, the mask value (0xCE) is wrong, it isn't checking the top-most bit: 11000001 value 11001110 mask (incorrect) ^ and should be (0xDE): 11000001 value 11011110 mask (correct) making the above code: } else if ( p[0] >= 0xC0 ) { if ( (p[0] & 0xE0) != 0xC0 ) { /* Skip illegal sequences return SDL_ICONV_EILSEQ; */ ch = UNKNOWN_UNICODE; } else { if ( (p[0] & 0xDE) == 0xC0 ) { <<<<<<<< here overlong = SDL_TRUE; } ch = (Uint32)(p[0] & 0x1F); left = 1; } } else { I can supply a test program and/or a patch if required, best regards, John Popplewell
src/stdlib/SDL_iconv.c
--- a/src/stdlib/SDL_iconv.c	Thu Dec 10 09:27:23 2009 +0000
+++ b/src/stdlib/SDL_iconv.c	Fri Dec 11 08:03:43 2009 +0000
@@ -391,7 +391,7 @@
                          */
                         ch = UNKNOWN_UNICODE;
                     } else {
-                        if ((p[0] & 0xCE) == 0xC0) {
+                        if ((p[0] & 0xDE) == 0xC0) {
                             overlong = SDL_TRUE;
                         }
                         ch = (Uint32) (p[0] & 0x1F);