From 0e518d5117b73fd54081decf1c0eb9f9d3173ff6 Mon Sep 17 00:00:00 2001
From: Uros Majstorovic <majstor@majstor.org>
Date: Wed, 29 Jul 2020 09:21:45 +0200
Subject: unicode support

---
 code/fe310/eos/eve/unicode.c | 103 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 code/fe310/eos/eve/unicode.c

(limited to 'code/fe310/eos/eve/unicode.c')

diff --git a/code/fe310/eos/eve/unicode.c b/code/fe310/eos/eve/unicode.c
new file mode 100644
index 0000000..62b1714
--- /dev/null
+++ b/code/fe310/eos/eve/unicode.c
@@ -0,0 +1,103 @@
+#include "unicode.h"
+
+uint8_t utf8_enc(utf32_t ch, utf8_t *str) {
+    if (ch <= 0x7f) {
+        str[0] = ch;
+        return 1;
+    } else if (ch <= 0x7ff) {
+        str[0] = 0xc0 | (ch >> 6);
+        str[1] = 0x80 | (ch & 0x3f);
+        return 2;
+    } else if (ch <= 0xffff) {
+        if ((ch >= 0xd800) && (ch <= 0xdfff)) return 0;
+        str[0] = 0xe0 | (ch >> 12);
+        str[1] = 0x80 | ((ch >> 6) & 0x3f);
+        str[2] = 0x80 | (ch & 0x3f);
+        return 3;
+    } else if (ch <= 0x10ffff) {
+        str[0] = 0xf0 | (ch >> 18);
+        str[1] = 0x80 | ((ch >> 12) & 0x3f);
+        str[2] = 0x80 | ((ch >> 6) & 0x3f);
+        str[3] = 0x80 | (ch & 0x3f);
+        return 4;
+    } else {
+        return 0;
+    }
+}
+
+uint8_t utf8_dec(utf8_t *str, utf32_t *ch) {
+    if ((str[0] & 0x80) == 0x00) {
+        *ch = str[0];
+        return 1;
+    } else if ((str[0] & 0xe0) == 0xc0) {
+        if ((str[1] & 0xc0) != 0x80) return 0;
+        *ch  = (utf32_t)(str[0] & 0x1f) << 6;
+        *ch |= (utf32_t)(str[1] & 0x3f);
+        if (*ch < 0x80) return 0;
+        return 2;
+    } else if ((str[0] & 0xf0) == 0xe0) {
+        if (((str[1] & 0xc0) != 0x80) || ((str[2] & 0xc0) != 0x80)) return 0;
+        *ch  = (utf32_t)(str[0] & 0x0f) << 12;
+        *ch |= (utf32_t)(str[1] & 0x3f) << 6;
+        *ch |= (utf32_t)(str[2] & 0x3f);
+        if ((*ch >= 0xd800) && (*ch <= 0xdfff)) return 0;
+        if (*ch < 0x800) return 0;
+        return 3;
+    } else if ((str[0] & 0xf8) == 0xf0) {
+        if (((str[1] & 0xc0) != 0x80) || ((str[2] & 0xc0) != 0x80) || ((str[3] & 0xc0) != 0x80)) return 0;
+        *ch  = (utf32_t)(str[0] & 0x07) << 18;
+        *ch |= (utf32_t)(str[1] & 0x0f) << 12;
+        *ch |= (utf32_t)(str[2] & 0x3f) << 6;
+        *ch |= (utf32_t)(str[3] & 0x3f);
+        if (*ch < 0x010000) return 0;
+        if (*ch > 0x10ffff) return 0;
+        return 4;
+    } else {
+        return 0;
+    }
+}
+
+int utf8_seek(utf8_t *str, int off, utf32_t *ch) {
+    int i;
+    int len = 0;
+
+    if (off < 0) {
+        off = -off;
+        for (i=0; i<off; i++) {
+            len--;
+            while ((*(str + len) & 0xc0) == 0x80) len--;
+        }
+        utf8_dec(str + len, ch);
+    } else {
+        for (i=0; i<off; i++) {
+            len += utf8_dec(str + len, ch);
+        }
+    }
+    return len;
+}
+
+int utf8_verify(utf8_t *str, int sz) {
+    utf32_t ch;
+    uint8_t ch_l;
+    int len = 0;
+
+    while (len < sz) {
+        if (sz - len < 4) {
+            if (((str[len] & 0xf8) == 0xf0) ||
+               (((str[len] & 0xf0) == 0xe0) && (sz - len < 3)) ||
+               (((str[len] & 0xe0) == 0xc0) && (sz - len < 2))) {
+                   str[len] = '\0';
+                   break;
+               }
+        }
+        ch_l = utf8_dec(str + len, &ch);
+        if (ch_l) {
+            if (ch == 0) break;
+            len += ch_l;
+        } else {
+            str[len] = '\0';
+            break;
+        }
+    }
+    return len;
+}
-- 
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