From 9324c85254fbc515528cf9370b4d8564d646f043 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <m@maandree.se>
Date: Sat, 31 Jan 2026 12:31:10 +0100
Subject: Misc
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Mattias Andrée <m@maandree.se>
---
 libcharconv_marchen.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 libcharconv_marchen.c

(limited to 'libcharconv_marchen.c')

diff --git a/libcharconv_marchen.c b/libcharconv_marchen.c
new file mode 100644
index 0000000..12fc414
--- /dev/null
+++ b/libcharconv_marchen.c
@@ -0,0 +1,134 @@
+/* See LICENSE file for copyright and license details. */
+#include "lib-common.h"
+
+
+enum libcharconv_result
+libcharconv_marchen(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
+{
+	static const char *const letters = "kKgGcCjYtTdnpPbmxXDwZz-yrlSsh";
+	uint_least32_t c, c2, c3;
+	size_t i;
+	*n = 0;
+	for (; slen--; s++) {
+		PLAIN_SELECT(letters, 0x11C72);
+		switch (s[0]) {
+		case 'a': c = UINT32_C(0x11C8F); goto conv1_subjoinable;
+		case 'A': c = UINT32_C(0x11CB0); goto conv_vowel;
+		case 'i': c = UINT32_C(0x11CB1); goto conv_vowel;
+		case 'u': c = UINT32_C(0x11CB2); goto conv_vowel;
+		case 'e': c = UINT32_C(0x11CB3); goto conv_vowel;
+		case 'o': c = UINT32_C(0x11CB4); goto conv_vowel;
+		case '\'': c = UINT32_C(0x11CB5); goto conv1;
+		case '\"': c = UINT32_C(0x11CB6); goto conv1;
+		case '.': c = UINT32_C(0x11C70); goto conv1;
+		case ':': c = UINT32_C(0x11C71); goto conv1;
+		case '^':
+			if (!slen)
+				return LIBCHARCONV_INDETERMINATE;
+			switch (s[1]) {
+			case 'A': c = UINT32_C(0x11CB0); goto conv2;
+			case 'i': c = UINT32_C(0x11CB1); goto conv2;
+			case 'u': c = UINT32_C(0x11CB2); goto conv2;
+			case 'e': c = UINT32_C(0x11CB3); goto conv2;
+			case 'o': c = UINT32_C(0x11CB4); goto conv2;
+			default:
+				goto no_match;
+			}
+		case '_':
+			if (*n)
+				goto no_conv;
+			*n += 1u;
+			break;
+		default:
+		no_match:
+			*n += 1u;
+			break;
+		}
+	}
+no_conv:
+	return LIBCHARCONV_NO_CONVERT;
+
+conv:
+	if (*n == 1u && s[-1] == '_' && c != UINT32_C(0x11C88)) {
+		c += 0x20u;
+		goto conv1_prechecked;
+	}
+	if (*n)
+		goto no_conv;
+	if (!slen)
+		return LIBCHARCONV_INDETERMINATE;
+	for (i = 0u; letters[i]; i++)
+		if (letters[i] == s[1])
+			break;
+	c3 = (letters[i] && letters[i] != '-') ? (uint_least32_t)(UINT32_C(0x11C92) + i) : 0u;
+	if (c3 && slen == 1u)
+		return LIBCHARCONV_INDETERMINATE;
+	switch (s[c3 ? 2 : 1]) {
+	case 'a':
+		if (c3)
+			goto conv3_prechecked;
+		else
+			goto conv2_prechecked;
+	case 'A': c2 = UINT32_C(0x11CB0); break;
+	case 'i': c2 = UINT32_C(0x11CB1); break;
+	case 'u': c2 = UINT32_C(0x11CB2); break;
+	case 'e': c2 = UINT32_C(0x11CB3); break;
+	case 'o': c2 = UINT32_C(0x11CB4); break;
+	default:
+		goto no_match;
+	}
+	if (*ncp >= 1u)
+		cp[0] = c;
+	if (*ncp >= 2u)
+		cp[1] = c2;
+	if (c3 && *ncp >= 3u)
+		cp[2] = c3;
+	*n += c3 ? 3u : 2u;
+	*ncp = c3 ? 3u : 2u;
+	return LIBCHARCONV_CONVERTED;
+
+conv1_subjoinable:
+	if (*n == 1u && s[-1] == '_') {
+		c += 0x20u;
+	} else {
+	conv1:
+		if (*n)
+			goto no_conv;
+	}
+conv1_prechecked:
+	if (*ncp)
+		*cp = c;
+	*n += 1u;
+	*ncp = 1u;
+	return LIBCHARCONV_CONVERTED;
+
+conv2:
+	if (*n)
+		goto no_conv;
+conv2_prechecked:
+	if (*ncp)
+		cp[0] = c;
+	*n += 2u;
+	*ncp = 1u;
+	return LIBCHARCONV_CONVERTED;
+
+conv_vowel:
+	if (*n)
+		goto no_conv;
+	if (*ncp >= 1u)
+		cp[0] = UINT32_C(0x11C8F) + (s[-1] == '_' ? 0x20u : 0u);
+	if (*ncp >= 2u)
+		cp[1] = c;
+	*n += 1u;
+	*ncp = 2u;
+	return LIBCHARCONV_CONVERTED;
+
+conv3_prechecked:
+	if (*ncp >= 1u)
+		cp[0] = c;
+	if (*ncp >= 2u)
+		cp[1] = c3;
+	*n += 3u;
+	*ncp = 2u;
+	return LIBCHARCONV_CONVERTED;
+}
-- 
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