From 13e9e58d77da2c041c2d0e6ea4c648bdcd14dc2c Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Sun, 25 Jan 2026 15:34:56 +0100 Subject: Add overlaid MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- libcharconv_overlaid.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 libcharconv_overlaid.c (limited to 'libcharconv_overlaid.c') diff --git a/libcharconv_overlaid.c b/libcharconv_overlaid.c new file mode 100644 index 0000000..7f3cab1 --- /dev/null +++ b/libcharconv_overlaid.c @@ -0,0 +1,66 @@ +/* See LICENSE file for copyright and license details. */ +#include "lib-common.h" + + +static struct { + uint_least32_t a; + uint_least32_t b; + uint_least32_t to; +} pairs[] = { + {0x00BF, 0x00A1, 0x2E18}, + {0x0021, 0x003F, 0x203D} +}; + + +enum libcharconv_result +libcharconv_overlaid(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp) +{ + uint_least32_t a, b; + size_t i, alen, blen; + *n = 0; + while (slen) { + alen = libcharconv_decode_utf8_(s, slen, &a); + if (alen > slen) { + if (*n) + goto no_conv; + return LIBCHARCONV_INDETERMINATE; + } + if (!alen) { + *n += 1u; + slen -= 1u; + s = &s[1]; + continue; + } + + for (i = 0u; i < sizeof(pairs) / sizeof(*pairs); i++) { + if (a != pairs[i].a && a != pairs[i].b) + continue; + if (*n) + goto no_conv; + if (slen == alen) + return LIBCHARCONV_INDETERMINATE; + blen = libcharconv_decode_utf8_(&s[alen], slen - alen, &b); + if (blen > slen) + return LIBCHARCONV_INDETERMINATE; + if (!blen) + goto no_conv; + if ((a ^ b) == (pairs[i].a ^ pairs[i].b)) + goto conv; + } + + *n += alen; + s = &s[alen]; + slen -= alen; + } +no_conv: + return LIBCHARCONV_NO_CONVERT; + +conv: + if (*n) + goto no_conv; + if (*ncp) + *cp = pairs[i].to; + *n += alen + blen; + *ncp = 1u; + return LIBCHARCONV_CONVERTED; +} -- cgit v1.2.3-70-g09d2