vui_utf8.c

#include <stdlib.h>

#include "vui_debug.h"

#include "vui_utf8.h"

static char vui_utf8_str[16];

char* vui_utf8_encode(unsigned int c, char* s)
{
	if (c < 0x80)
	{
		*s++ = c;
	}
	else if (c < 0x800)
	{
		*s++ = 192 | ((c >>  6) & 0x1F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
	else if (c < 0x10000)
	{
		*s++ = 224 | ((c >> 12) & 0x0F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
	else if (c < 0x200000)
	{
		*s++ = 240 | ((c >> 18) & 0x07);
		*s++ = 128 | ((c >> 12) & 0x3F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
	else if (c < 0x4000000)
	{
		*s++ = 248 | ((c >> 24) & 0x03);
		*s++ = 128 | ((c >> 18) & 0x3F);
		*s++ = 128 | ((c >> 12) & 0x3F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
	else if (c < 0x80000000)
	{
		*s++ = 252 | ((c >> 30) & 0x01);
		*s++ = 128 | ((c >> 24) & 0x3F);
		*s++ = 128 | ((c >> 18) & 0x3F);
		*s++ = 128 | ((c >> 12) & 0x3F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
#if VUI_UTF8_EXTRA
	else if (c < 0x1000000000)
	{
		*s++ = 254 | ((c >> 36) & 0x00);
		*s++ = 128 | ((c >> 30) & 0x3F);
		*s++ = 128 | ((c >> 24) & 0x3F);
		*s++ = 128 | ((c >> 18) & 0x3F);
		*s++ = 128 | ((c >> 12) & 0x3F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
	else if (c < 0x20000000000)
	{
		*s++ = 255 | ((c >> 40) & 0x00);
		*s++ = 128 | ((c >> 36) & 0x3F);
		*s++ = 128 | ((c >> 30) & 0x3F);
		*s++ = 128 | ((c >> 24) & 0x3F);
		*s++ = 128 | ((c >> 18) & 0x3F);
		*s++ = 128 | ((c >> 12) & 0x3F);
		*s++ = 128 | ((c >>  6) & 0x3F);
		*s++ = 128 | ((c >>  0) & 0x3F);
	}
#endif
#if defined(VUI_DEBUG) && defined(VUI_DEBUG_UTF8)
	else
	{
		vui_debugf("Error: can't encode value as UTF-8: %d\n", c);
	}
#endif

	*s = 0;

	return s;
}

vui_string* vui_utf8_encode_str(unsigned int c)
{
	vui_string* str = vui_string_new_prealloc(16);
	str->n = vui_utf8_encode(c, str->s) - str->s;
	vui_string_shrink(str);
	return str;
}

char* vui_utf8_encode_alloc(unsigned int c)
{
	vui_string str;
	vui_string_new_prealloc_at(&str, 16);
	str.n = vui_utf8_encode(c, str.s) - str.s;
	return vui_string_get(&str);
}

char* vui_utf8_encode_static(unsigned int c)
{
	vui_utf8_encode(c, vui_utf8_str);
	return vui_utf8_str;
}