Function UtfToLocal

src/backend/utils/mb/conv.c:506–689

* UTF8 ---> local code * * utf: input string in UTF8 encoding (need not be null-terminated) * len: length of input string (in bytes) * iso: pointer to the output area (must be large enough!) (output string will be null-terminated) * map: conversion map for single characters * cmap: conversion map for combined characters * (optional, pass NULL if none) * cmapsize: number of entries i

 * be less than 'len'.
 */
int
UtfToLocal(const unsigned char *utf, int len,
		   unsigned char *iso,
		   const pg_mb_radix_tree *map,
		   const pg_utf_to_local_combined *cmap, int cmapsize,
		   utf_local_conversion_func conv_func,
		   int encoding, bool noError)
{
	uint32		iutf;
	int			l;
	const pg_utf_to_local_combined *cp;
	const unsigned char *start = utf;

	if (!PG_VALID_ENCODING(encoding))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid encoding number: %d", encoding)));

	for (; len > 0; len -= l)
	{
		unsigned char b1 = 0;
		unsigned char b2 = 0;
		unsigned char b3 = 0;
		unsigned char b4 = 0;

		/* "break" cases all represent errors */
		if (*utf == '\0')
			break;

		l = pg_utf_mblen(utf);
		if (len < l)
			break;

		if (!pg_utf8_islegal(utf, l))
			break;

		if (l == 1)
		{
			/* ASCII case is easy, assume it's one-to-one conversion */
			*iso++ = *utf++;
			continue;
		}

		/* collect coded char of length l */
		if (l == 2)
		{
			b3 = *utf++;
			b4 = *utf++;
		}
		else if (l == 3)
		{
			b2 = *utf++;
			b3 = *utf++;
			b4 = *utf++;
		}
		else if (l == 4)
		{
			b1 = *utf++;