fix iconv conversions to legacy 8bit encodings

there was missing reverse-conversion logic for the case, handled
specially in the character set tables, where a byte represents a
unicode codepoint with the same value.

this patch adds code to handle the case, and refactors the two-level
10-bit table lookup for legacy character sets into a function to avoid
repeating it yet another time as part of the fix.

diff --git a/src/locale/iconv.c b/src/locale/iconv.c
index 1eeea94e0a38753691269b978f105b5e65ee33b8..4636307f82c37404db2f76f9a13a7ff9f235dd2b 100644 (file)
--- a/src/locale/iconv.c
+++ b/src/locale/iconv.c
@@ -151,6 +151,14 @@ static void put_32(unsigned char *s, unsigned c, int e)
 #define mbrtowc_utf8 mbrtowc
 #define wctomb_utf8 wctomb
 
+static unsigned legacy_map(const unsigned char *map, unsigned c)
+{
+       unsigned x = c - 128 + map[-1];
+       x = legacy_chars[ map[x*5/4]>>2*x%8 |
+               map[x*5/4+1]<<8-2*x%8 & 1023 ];
+       return x ? x : c;
+}
+
 size_t iconv(iconv_t cd0, char **restrict in, size_t *restrict inb, char **restrict out, size_t *restrict outb)
 {
        size_t x=0;
@@ -364,10 +372,7 @@ size_t iconv(iconv_t cd0, char **restrict in, size_t *restrict inb, char **restr
                        break;
                default:
                        if (c < 128+type) break;
-                       c -= 128+type;
-                       c = legacy_chars[ map[c*5/4]>>2*c%8 |
-                               map[c*5/4+1]<<8-2*c%8 & 1023 ];
-                       if (!c) c = *(unsigned char *)*in;
+                       c = legacy_map(map, c);
                        if (c==1) goto ilseq;
                }
 
@@ -392,17 +397,15 @@ size_t iconv(iconv_t cd0, char **restrict in, size_t *restrict inb, char **restr
                        if (c > 0x7f) subst: x++, c='*';
                default:
                        if (*outb < 1) goto toobig;
-                       if (c < 128+totype) {
+                       if (c < 128+totype || (c<256 && c==legacy_map(tomap, c))) {
                        revout:
                                *(*out)++ = c;
                                *outb -= 1;
                                break;
                        }
                        d = c;
-                       for (c=0; c<128-totype; c++) {
-                               if (d == legacy_chars[ tomap[c*5/4]>>2*c%8 |
-                                       tomap[c*5/4+1]<<8-2*c%8 & 1023 ]) {
-                                       c += 128;
+                       for (c=128+totype; c<256; c++) {
+                               if (d == legacy_map(tomap, c)) {
                                        goto revout;
                                }
                        }