handle ascii range individually in each iconv case

short-circuiting low bytes before the switch precluded support for
character encodings that don't coincide with ascii in this range. this
limitation affected iso-2022 encodings, which use the esc byte to
introduce a shift sequence, and things like ebcdic.

diff --git a/src/locale/iconv.c b/src/locale/iconv.c
index c64bcf3..af0d828 100644 (file)
--- a/src/locale/iconv.c
+++ b/src/locale/iconv.c
@@ -193,8 +193,9 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                c = *(unsigned char *)*in;
                l = 1;
 
-               if (c >= 128 || type-UTF_32BE < 7U) switch (type) {
+               switch (type) {
                case UTF_8:
+                       if (c < 128) break; // optimization
                        l = mbrtowc_utf8(&wc, *in, *inb, &st);
                        if (!l) l++;
                        else if (l == (size_t)-1) goto ilseq;
@@ -202,7 +203,8 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        c = wc;
                        break;
                case US_ASCII:
-                       goto ilseq;
+                       if (c >= 128) goto ilseq;
+                       break;
                case WCHAR_T:
                        l = sizeof(wchar_t);
                        if (*inb < l) goto starved;
@@ -234,6 +236,7 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        }
                        break;
                case SHIFT_JIS:
+                       if (c < 128) break;
                        if (c-0xa1 <= 0xdf-0xa1) {
                                c += 0xff61-0xa1;
                                break;
@@ -257,6 +260,7 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        if (!c) goto ilseq;
                        break;
                case EUC_JP:
+                       if (c < 128) break;
                        l = 2;
                        if (*inb < 2) goto starved;
                        d = *((unsigned char *)*in + 1);
@@ -273,9 +277,11 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        if (!c) goto ilseq;
                        break;
                case GB2312:
+                       if (c < 128) break;
                        if (c < 0xa1) goto ilseq;
                case GBK:
                case GB18030:
+                       if (c < 128) break;
                        c -= 0x81;
                        if (c >= 126) goto ilseq;
                        l = 2;
@@ -311,6 +317,7 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        c = gb18030[c][d];
                        break;
                case BIG5:
+                       if (c < 128) break;
                        l = 2;
                        if (*inb < 2) goto starved;
                        d = *((unsigned char *)*in + 1);
@@ -348,6 +355,7 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
                        if (!c) goto ilseq;
                        break;
                case EUC_KR:
+                       if (c < 128) break;
                        l = 2;
                        if (*inb < 2) goto starved;
                        d = *((unsigned char *)*in + 1);