Function get_valid_string

lib_acl_cpp/samples/rfc2047/main.cpp:28–74

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// �����Ч�ĺ����ַ�
static int get_valid_string(char *src, unsigned dlen, char *buffer, unsigned bsize)
{
	int n = 0;
	unsigned char *src_ptr = NULL;
	unsigned char *obj_ptr = NULL;
	unsigned char *ch = NULL;
	int firstChineseChar = 0;
	char lastChar = 0;

	if (src == NULL || dlen == 0 || buffer == NULL || bsize == 0)
		return -1;

	obj_ptr = (unsigned char *)buffer;

	src_ptr = (unsigned char *)src;

	/* Ϊ���һ�� '\0' ����һ���ֽڿռ� */
	n =  bsize - 1;

	for (ch = src_ptr; *ch; ch++) {
		if (ch - src_ptr >= n)
			break;

		/* ���ж�ǰһ���ֽ����λ�Ƿ�Ϊ 1 */
		if (firstChineseChar) {
			if (!isvalidChinese(lastChar,*ch))
				break;

			//if (ch - src_ptr >= n + 1)
			//	break;

			firstChineseChar = 0; 
			/* �ȿ���ǰһ���ֽ� */
			*obj_ptr++ = lastChar;
			*obj_ptr++ = *ch;
		}
		else if ((*ch) & 0x80) {
			/* ˵����ǰ�ֽڵ����λΪ 1, ���п����Ǻ��ֵĵ�һ���ֽ� */
			firstChineseChar = 1;
			lastChar = *ch;
		}
		else
			*obj_ptr++ = *ch;
	}
	*obj_ptr = 0;
	return 0;
}

static void rfc2047_test(acl::rfc2047& rfc2047, const char* s)
{