#include "acl_stdafx.hpp"
#include "acl_cpp/stdlib/string.hpp"
#include "header_opts.hpp"
#include "tok822.hpp"
#include "rec_type.hpp"
#include "lex_822.hpp"
#include "rec_type.hpp"
#include "mime_state.hpp"

#if !defined(ACL_MIME_DISABLE)

#define SCP(x, s)	acl_vstring_strcpy((x), (s))
#define SCAT(x, s)	acl_vstring_strcat((x), (s))
#define STR(x)		acl_vstring_str((x))
#define LEN(x)		ACL_VSTRING_LEN((x))
#define END(x)		acl_vstring_end((x))
#define TERM(x)		ACL_VSTRING_TERMINATE((x))
#define ADDCH(x, ch)	{ ACL_VSTRING_ADDCH((x), (ch)); TERM((x)); }
#define APPEND(x, s, n)	{ acl_vstring_memcat((x), (s), (n)); TERM((x)); }
#define EQUAL(x, y)	!strcasecmp((x), (y))

/*
* MIME encodings and domains. We intentionally use the same codes for
* encodings and domains, so that we can easily find out whether a content
* transfer encoding header specifies a domain or whether it specifies
* domain+encoding, which is illegal for multipart/any and message/any.
*/
typedef struct MIME_ENCODING {
	const char *name;       /* external representation */
	int     encoding;       /* internal representation */
	int     domain;         /* subset of encoding */
} MIME_ENCODING;

static const MIME_ENCODING mime_encoding_map[] = {      /* RFC 2045 */
	{ "7bit", MIME_ENC_7BIT, MIME_ENC_7BIT },       /* domain */
	{ "8bit", MIME_ENC_8BIT, MIME_ENC_8BIT },       /* domain */
	{ "binary", MIME_ENC_BINARY, MIME_ENC_BINARY }, /* domain */
	{ "base64", MIME_ENC_BASE64, MIME_ENC_7BIT },   /* encoding */
	{ "uucode", MIME_ENC_UUCODE, MIME_ENC_7BIT },   /* encoding */
	{ "xxcode", MIME_ENC_XXCODE, MIME_ENC_7BIT },   /* encoding */
	{ "quoted-printable", MIME_ENC_QP, MIME_ENC_7BIT }, /* encoding */
	{ 0, 0, 0 },
};

/*-------------------------------------------------------------------------*/

#define RFC2045_TSPECIALS	"()<>@,;:\\\"/[]?="
//#define RFC2045_TSPECIALS	"()<>@,;:\"/[]?="
#define TOKEN_MATCH(tok, text) \
	((tok).type == HEADER_TOK_TOKEN && EQUAL((tok).u.value, (text)))

static void mime_content_type(MIME_NODE *node, const HEADER_OPTS *header_info)
{
	const char *cp;
	ssize_t tok_count;
	MIME_STATE *state = node->state;

#define PARSE_CONTENT_TYPE_HEADER(state, ptr) \
	header_token(state->token, MIME_MAX_TOKEN, \
		state->token_buffer, ptr, RFC2045_TSPECIALS, ';')

	cp = STR(node->buffer) + strlen(header_info->name) + 1;
	if ((tok_count = PARSE_CONTENT_TYPE_HEADER(state, &cp)) <= 0) {

		/*
		 * other/whatever.
		 */
		node->ctype = MIME_CTYPE_OTHER;
		return;
	}

	/* tok_count > 0 */

	if (state->token[0].type == HEADER_TOK_TOKEN)
		node->ctype_s = acl_mystrdup(state->token[0].u.value);
	if (tok_count >= 3 && state->token[1].type == '/'
		&& state->token[2].type == HEADER_TOK_TOKEN)
	{
		node->stype_s = acl_mystrdup(state->token[2].u.value);
	}

	/*
	 * message/whatever body parts start with another block of message
	 * headers that we may want to look at. The partial and external-body
	 * subtypes cannot be subjected to 8-bit -> 7-bit conversion, so we
	 * must properly recognize them.
	 */
	if (TOKEN_MATCH(state->token[0], "message")) {
		node->ctype = MIME_CTYPE_MESSAGE;
		node->stype = MIME_STYPE_OTHER;
		if (tok_count >= 3 && state->token[1].type == '/') {
			if (TOKEN_MATCH(state->token[2], "rfc822"))
				node->stype = MIME_STYPE_RFC822;
			else if (TOKEN_MATCH(state->token[2], "partial"))
				node->stype = MIME_STYPE_PARTIAL;
			else if (TOKEN_MATCH(state->token[2], "external-body"))
				node->stype = MIME_STYPE_EXTERN_BODY;
		}
	}

	/*
	 * multipart/digest has default content type message/rfc822,
	 * multipart/whatever has default content type text/plain.
	 */
	else if (TOKEN_MATCH(state->token[0], "multipart")) {
		node->ctype = MIME_CTYPE_MULTIPART;
		if (tok_count >= 3 && state->token[1].type == '/') {
			if (TOKEN_MATCH(state->token[2], "digest")) {
				node->ctype = MIME_CTYPE_MESSAGE;
				node->stype = MIME_STYPE_RFC822;
			} else if (TOKEN_MATCH(state->token[2], "alternative")) {
				node->stype = MIME_STYPE_ALTERNATIVE;
			} else if (TOKEN_MATCH(state->token[2], "related")) {
				node->stype = MIME_STYPE_RELATED;
			} else if (TOKEN_MATCH(state->token[2], "mixed")) {
				node->stype = MIME_STYPE_MIXED;
			} else {
				node->stype = MIME_STYPE_OTHER;
			}
		} else {
			node->ctype = MIME_CTYPE_TEXT;
			node->stype = MIME_STYPE_PLAIN;
		}

		/*
		 * Yes, this is supposed to capture multiple boundary strings,
		 * which are illegal and which could be used to hide content
		 * in an implementation dependent manner. The code below allows
		 * us to find embedded message headers as long as the sender
		 * uses only one of these same-level boundary strings.
		 * 
		 * Yes, this is supposed to ignore the boundary value type.
		 */
		while ((tok_count = PARSE_CONTENT_TYPE_HEADER(state, &cp)) >= 0) {
			if (tok_count < 3 || state->token[1].type != '=')
				continue;
			if (TOKEN_MATCH(state->token[0], "boundary")) {
				if (node->boundary == NULL)
					node->boundary = acl_vstring_alloc(256);
				/* 需要添加 "--" 做为分隔符的前导符 */
				SCP(node->boundary, "--");
				SCAT(node->boundary, state->token[2].u.value);
				break;
			}
		}
	}

	/*
	 * text/whatever. Right now we don't really care if it is plain or
	 * not, but we may want to recognize subtypes later, and then this
	 * code can serve as an example.
	 */
	else if (TOKEN_MATCH(state->token[0], "text")) {
		node->ctype = MIME_CTYPE_TEXT;
		if (tok_count >= 3 && state->token[1].type == '/') {
			if (TOKEN_MATCH(state->token[2], "plain"))
				node->stype = MIME_STYPE_PLAIN;
			else if (TOKEN_MATCH(state->token[2], "html"))
				node->stype = MIME_STYPE_HTML;
			else
				node->stype = MIME_STYPE_OTHER;
		} else
			node->stype = MIME_STYPE_OTHER;

		while ((tok_count = PARSE_CONTENT_TYPE_HEADER(state, &cp)) >= 0) {
			if (tok_count < 3 || state->token[1].type != '=')
				continue;
			if (TOKEN_MATCH(state->token[0], "charset")
				&& node->charset == NULL)
			{
				node->charset = acl_mystrdup(state->token[2].u.value);
				break;
			}
		}

		/* 如果没有字符集, 则缺省采用 gb2312 */
		if (node->charset == NULL)
			node->charset = acl_mystrdup("gb2312");
	}
	else if (TOKEN_MATCH(state->token[0], "image")) {
		node->ctype = MIME_CTYPE_IMAGE;
		if (tok_count >= 3 && state->token[1].type == '/') {
			if (TOKEN_MATCH(state->token[2], "jpeg"))
				node->stype = MIME_STYPE_JPEG;
			else if (TOKEN_MATCH(state->token[2], "gif"))
				node->stype = MIME_STYPE_GIF;
			else if (TOKEN_MATCH(state->token[2], "bmp"))
				node->stype = MIME_STYPE_BMP;
			else if (TOKEN_MATCH(state->token[2], "png"))
				node->stype = MIME_STYPE_PNG;
			else
				node->stype = MIME_STYPE_OTHER;
		} else
			node->stype = MIME_STYPE_OTHER;

		while ((tok_count = PARSE_CONTENT_TYPE_HEADER(state, &cp)) >= 0) {
			if (tok_count < 3 || state->token[1].type != '=')
				continue;
			if (TOKEN_MATCH(state->token[0], "name")
				&& node->header_name == NULL)
			{
				node->header_name = acl_mystrdup(state->token[2].u.value);
				break;
			}
		}
	}
	else if (TOKEN_MATCH(state->token[0], "application")) {
		node->ctype = MIME_CTYPE_APPLICATION;
		if (tok_count >= 3 && state->token[1].type == '/') {
			if (TOKEN_MATCH(state->token[2], "octet-stream"))
				node->stype = MIME_STYPE_OCTET_STREAM;
			else
				node->stype = MIME_STYPE_OTHER;
		}
		while ((tok_count = PARSE_CONTENT_TYPE_HEADER(state, &cp)) >= 0) {
			if (tok_count < 3 || state->token[1].type != '=')
				continue;
			if (TOKEN_MATCH(state->token[0], "name")
				&& node->header_name == NULL)
			{
				node->header_name = acl_mystrdup(state->token[2].u.value);
				break;
			}
		}
	}
}

/* mime_state_content_encoding - process content-transfer-encoding header */

static void mime_content_encoding(MIME_NODE *node,
	const HEADER_OPTS *header_info)
{
	MIME_STATE *state = node->state;
	const char *cp;
	const MIME_ENCODING *cmp;

#define PARSE_CONTENT_ENCODING_HEADER(state, ptr) \
	header_token(state->token, 1, state->token_buffer, ptr, (char *) 0, 0)

	/*
	 * Do content-transfer-encoding header. Never set the encoding domain
	 * to something other than 7bit, 8bit or binary, even if we don't
	 * recognize the input.
	 */
	cp = STR(node->buffer) + strlen(header_info->name) + 1;
	if (PARSE_CONTENT_ENCODING_HEADER(state, &cp) > 0
		&& state->token[0].type == HEADER_TOK_TOKEN)
	{
		for (cmp = mime_encoding_map; cmp->name != 0; cmp++) {
			if (EQUAL(state->token[0].u.value, cmp->name)) {
				node->encoding = cmp->encoding;
				node->domain = cmp->domain;
				break;
			}
		}
	}
}

static void mime_content_disposition(MIME_NODE *node,
	const HEADER_OPTS *header_info)
{
	const char *cp = STR(node->buffer) + strlen(header_info->name) + 1;
	ssize_t tok_count;

#define PARSE_CONTENT_DISPOSITION(state, ptr) \
	header_token(state->token, MIME_MAX_TOKEN, \
		state->token_buffer, ptr, RFC2045_TSPECIALS, ';')

	while (1) {
		tok_count = PARSE_CONTENT_DISPOSITION(node->state, &cp);
		if (tok_count <= 0)
			break;

		if (tok_count < 3 || node->state->token[1].type != '=')
			continue;

		if (TOKEN_MATCH(node->state->token[0], "filename")
			&& node->header_filename == NULL)
		{
			node->header_filename =
				acl_mystrdup(node->state->token[2].u.value);
		} else if (TOKEN_MATCH(node->state->token[0], "name")
			&& node->header_name == NULL)
		{
			node->header_name =
				acl_mystrdup(node->state->token[2].u.value);
		}
	}
}

/* mime_state_downgrade - convert 8-bit data to quoted-printable */

void mime_state_downgrade(MIME_STATE *state, int rec_type,
	const char *text, ssize_t len)
{
	static char hexchars[] = "0123456789ABCDEF";
	const unsigned char *cp;
	MIME_NODE *node = state->curr_node;
	int     ch;

#define CU_CHAR_PTR(x)	((const unsigned char *) (x))
#define QP_ENCODE(buffer, ch) { \
	buffer += '='; \
	buffer += (char) hexchars[(ch >> 4) & 0xff]; \
	buffer += (char) hexchars[ch & 0xf]; \
}

	/*
	 * Insert a soft line break when the output reaches a critical length
	 * before we reach a hard line break.
	 */
	for (cp = CU_CHAR_PTR(text); cp < CU_CHAR_PTR(text + len); cp++) {
		/* Critical length before hard line break. */
		if (LEN(node->buffer) > 72) {
			node->buffer += '=';
		}
		/* Append the next character. */
		ch = *cp;
		if ((ch < 32 && ch != '\t') || ch == '=' || ch > 126) {
			QP_ENCODE(node->buffer, ch);
		} else {
			ADDCH(node->buffer, ch);
		}
	}

	/*
	 * Flush output after a hard line break (i.e. the end of a REC_TYPE_NORM
	 * record). Fix trailing whitespace as per the RFC: in the worst case,
	 * the output length will grow from 73 characters to 75 characters.
	 */
	if (rec_type == REC_TYPE_NORM) {
		if (LEN(node->buffer) > 0
			&& ((ch = END(node->buffer)[-1]) == ' ' || ch == '\t'))
		{
			acl_vstring_truncate(node->buffer, LEN(node->buffer) - 1);
			QP_ENCODE(node->buffer, ch);
		}
		ACL_VSTRING_TERMINATE(node->buffer);
	}
}

static ACL_FIFO *mail_addr_add(ACL_FIFO *addr_list, const char *addr)
{
	MAIL_ADDR *mail_addr;

	if (addr_list == NULL)
		addr_list = acl_fifo_new();
	mail_addr = (MAIL_ADDR*) acl_mycalloc(1, sizeof(MAIL_ADDR));
	mail_addr->addr = acl_mystrdup(addr);
	acl_fifo_push(addr_list, mail_addr);
	return addr_list;
}

static void mail_rcpt(MIME_NODE *node, const HEADER_OPTS *header_info)
{
	TOK822 *tree;
	TOK822 **addr_list;
	TOK822 **tpp;
	ACL_VSTRING *temp;
	const char *cp;

	temp = acl_vstring_alloc(10);
	cp = STR(node->buffer) + strlen(header_info->name) + 1;
	tree = tok822_parse(cp);
	addr_list = tok822_grep(tree, TOK822_ADDR);
	for (tpp = addr_list; *tpp; tpp++) {
		tok822_internalize(temp, tpp[0]->head, TOK822_STR_DEFL);
		if (header_info->type == HDR_TO) {
			node->header_to_list =
				mail_addr_add(node->header_to_list, STR(temp));
		} else if (header_info->type == HDR_CC) {
			node->header_cc_list =
				mail_addr_add(node->header_cc_list, STR(temp));
		} else if (header_info->type == HDR_BCC) {
			node->header_bcc_list =
				mail_addr_add(node->header_bcc_list, STR(temp));
		}
	}

	acl_myfree(addr_list);
	tok822_free_tree(tree);
	acl_vstring_free(temp);
}

static void mail_from(MIME_NODE *node, const HEADER_OPTS *header_info)
{
	/* MIME_STATE *state = node->state; */
	TOK822 *tree;
	TOK822 **addr_list;
	TOK822 **tpp;
	ACL_VSTRING *temp;
	const char *cp;

	temp = acl_vstring_alloc(10);
	cp = STR(node->buffer) + strlen(header_info->name) + 1;
	tree = tok822_parse(cp);
	addr_list = tok822_grep(tree, TOK822_ADDR);
	for (tpp = addr_list; *tpp; tpp++) {
		tok822_internalize(temp, tpp[0]->head, TOK822_STR_DEFL);
		if (header_info->type == HDR_SENDER) {
			if (node->header_sender)
				acl_myfree(node->header_sender);
			node->header_sender = acl_mystrdup(STR(temp));
			break;
		} else if (header_info->type == HDR_FROM) {
			if (node->header_from)
				acl_myfree(node->header_from);
			node->header_from = acl_mystrdup(STR(temp));
			break;
		} else if (header_info->type == HDR_REPLY_TO) {
			if (node->header_replyto)
				acl_myfree(node->header_replyto);
			node->header_replyto = acl_mystrdup(STR(temp));
			break;
		} else if (header_info->type == HDR_RETURN_PATH) {
			if (node->header_returnpath)
				acl_myfree(node->header_returnpath);
			node->header_returnpath = acl_mystrdup(STR(temp));
		}
	}

	acl_myfree(addr_list);
	
	tok822_free_tree(tree);
	acl_vstring_free(temp);
}

static void mail_subject(MIME_NODE *node, const HEADER_OPTS *header_info)
{
	const char *cp;

	if (header_info->type != HDR_SUBJECT)
		return;

	cp = STR(node->buffer) + strlen(header_info->name) + 1;
	if (strlen(cp) == 0)
		return;
	if (node->header_subject)
		acl_myfree(node->header_subject);
	node->header_subject = acl_mystrdup(cp);
}

static void mime_header_line(MIME_NODE *node)
{
	const HEADER_OPTS *header_info;
	size_t len = LEN(node->buffer);
	char *ptr = strrchr(STR(node->buffer), '\n');

	if (ptr) {
		*ptr-- = 0;
		len--;
		if (ptr > STR(node->buffer)) {
			if (*ptr == '\r') {
				*ptr = 0;
				len--;
			}
		}
		if (len == 0)
			return;

		acl_vstring_truncate(node->buffer, len);
	}

	header_info = header_opts_find(STR(node->buffer), node->state->key_buffer);
	if (header_info) {
		if (header_info->type == HDR_CONTENT_TYPE)
			mime_content_type(node, header_info);
		else if (header_info->type == HDR_CONTENT_TRANSFER_ENCODING)
			mime_content_encoding(node, header_info);
		else if (node == node->state->root) {
			/* 说明邮件头 */

			if ((header_info->flags & HDR_OPT_RECIP)
				&& (header_info->flags & HDR_OPT_EXTRACT))
			{
				/* 分析收件人地址: To, Cc, Bcc */
				mail_rcpt(node, header_info);
			} else if ((header_info->flags & HDR_OPT_SENDER)) {
				/* 分析发件人地址: From, Sender,
				 * Replyto, Returnpath
				 */
				mail_from(node, header_info);
			} else if ((header_info->flags & HDR_OPT_SUBJECT)) {
				mail_subject(node, header_info);
			}
		} else if (header_info->type == HDR_CONTENT_DISPOSITION) {
			mime_content_disposition(node, header_info);
		}
	}

	if (node->header_list) {
		HEADER_NV *header = header_split(STR(node->buffer));
		if (header)
			node->header_list->push_back(node->header_list, header);
	}

	ACL_VSTRING_RESET(node->buffer); /* 清空缓冲区 */
	node->last_ch = 0;
	node->last_lf = 0;
}

/* 状态机数据结构类型 */

struct MIME_STATUS_MACHINE {
	/**< 状态码 */
	int   status;

	/**< 状态机处理函数 */
	int (*callback) (MIME_STATE*, const char*, int);
};

// 分析邮件头及 multipart 各部分的头
static int mime_state_head(MIME_STATE *state, const char *s, int n)
{
	MIME_NODE *node = state->curr_node;

	if (n <= 0)
		return n;

	/* 如果还未找到换行符，则继续 */

	if (node->last_lf != '\n') {
		while (n > 0) {
			node->last_ch = *s;
			ADDCH(node->buffer, node->last_ch);
			n--;
			state->curr_off++;

			if (node->last_ch == '\n') {
				node->last_lf = '\n';
				break;
			}
			s++;
		}

		return n;
	}

	/* 如果数据以换行开始， 说明当前的邮件头结束 */

	if (*s == '\n') {
		/* 上次数据为: \n\r 或 \n */

		state->curr_off++;
		node->header_end = state->curr_off;

		if (LEN(node->buffer) > 0) {
			/* 处理头部的最后一行数据 */
			mime_header_line(node);
			node->valid_line++;
		}

		/* 略过开头无用的空行 */
		if (node->valid_line == 0)
			return 0;

		/* 如果当前结点为 multipart 格式, 则重置 state->curr_bound */
		if (node->boundary != NULL)
			state->curr_bound = STR(node->boundary);
		state->curr_status = MIME_S_BODY;
		node->body_begin = state->curr_off;
		return n - 1;
	}
	if (*s == '\r') {
		state->curr_off++;
		if (node->last_ch == '\r') {
			/* XXX: 出现了 \n\r\r 现象 */
			node->last_ch = '\r';
			node->last_lf = 0;
			return n - 1;
		}

		node->last_ch = '\r';
		/* 返回, 以期待下一个字符为 '\n' */
		return n - 1;
	}

	/* 清除 '\n' */
	node->last_lf = 0;

	/* 如果数据以空格或TAB开始， 说明数据附属于上一行 */

	if (IS_SPACE_TAB(*s)) {
		/* 说明本行数据附属于上一行数据 */
		while (n > 0) {
			node->last_ch = *s;
			ADDCH(node->buffer, node->last_ch);
			n--;
			state->curr_off++;

			if (node->last_ch == '\n') {
				/* 处理完本完整行数据 */
				node->last_lf = '\n';
				break;
			}
			s++;
		}

		return n;
	}

	/* 处理头部的上一行数据 */

	if (LEN(node->buffer) > 0) {
		mime_header_line(node);
		node->valid_line++;
	}

	return n;
}

// 分析 multipart 部分体, 当匹配到一个完整的分隔符后则表明该部分数据体分析完毕
static int mime_bound_body(MIME_STATE *state, const char * const boundary,
	MIME_NODE *node, const char *s, int n, int *finish)
{
	const unsigned char *cp  = (const unsigned char*) s;
	const unsigned char *end = (const unsigned char*) s + n;
	size_t bound_len         = strlen(boundary);
	off_t curr_off           = state->curr_off;
	off_t last_cr_pos        = node->last_cr_pos;
	off_t last_lf_pos        = node->last_lf_pos;
	const char *bound_ptr    = node->bound_ptr;

	for (; cp < end; cp++) {

		// 记录下 \r\n 的位置
		if (*cp == '\r')
			last_cr_pos = curr_off;
		else if (*cp == '\n')
			last_lf_pos = curr_off;

		curr_off++;

		if (bound_ptr == NULL) {
			if (*cp != *boundary)
				continue;

			bound_ptr = boundary;
		}
		
		if (*cp != *bound_ptr) {
			bound_ptr = NULL;
		} else if (*++bound_ptr == 0) {

			/* 说明完全匹配 */
			*finish = 1;

			node->body_end = (off_t) (curr_off - bound_len);
			node->body_data_end = node->body_end;

			// body_end 记录的是某个结点最后的位置，根据协议,
			// 其中会包含附加的 \r\n，所以真实数据的结束位置
			// body_data_end 是去掉这些数据后的位置
			if (last_lf_pos + (off_t) bound_len == curr_off - 1)
			{
				node->body_data_end--;
				if (last_cr_pos + 1 == last_lf_pos)
					node->body_data_end--;
			}

			bound_ptr = NULL;
			cp++;
			break;
		}
	}

	node->bound_ptr   = bound_ptr;
	node->last_cr_pos = last_cr_pos;
	node->last_lf_pos = last_lf_pos;
	state->curr_off   = curr_off;

	return (int) (n - ((const char*) cp - s));
}

// 分析邮件体或 multipart 部分体
static int mime_state_body(MIME_STATE *state, const char *s, int n)
{
	int   finish = 0;

	if (state->curr_bound == NULL) {

		/* 如果没有分隔符，则说明是文本类型，即只有正文内容 */

		state->curr_off += n;

		/* 因为 curr_off 指向下一个偏移位置，所以
		 * body_end = curr_off - 1
		 */
		state->curr_node->body_end = state->curr_off - 1;
		state->curr_node->body_data_end = state->curr_node->body_end;
		return 0;
	}

	n  = mime_bound_body(state, state->curr_bound,
			state->curr_node, s, n, &finish);
	if (finish)
		state->curr_status = MIME_S_BODY_BOUND_CRLF;

	return n;
}

// 查找分隔符后的 "\r\n"
static int mime_state_body_bound_crlf(MIME_STATE *state, const char *s, int n)
{
	if (n <= 0)
		return n;

	/* 如果不是分隔符的最后两个 "--" 则说明还由其它结点由本分隔符分隔 */

	if (*s == '\n') {
		state->curr_node->last_lf_pos = state->curr_off;
		state->curr_node->last_ch = '\n';
		
		state->curr_off++;
		state->curr_node->bound_end = state->curr_off;

		/*
		state->curr_node->body_end = state->curr_node->bound_end
			- strlen(state->curr_bound) - 1;
		if (state->curr_node->last_ch == '\r')
			state->curr_node->body_end--;
		*/

		/* 如果结束符为 "--\r\n", 说明不仅结点结束,
		 * 同时本结点的父结点也结束
		 */
		if (state->curr_node->bound_term[0] == '-'
			&& state->curr_node->bound_term[1] == '-')
		{
			/* 说明本分隔符所约束的结点完毕 */

			if (state->curr_node == state->root) {
				/* xxx: 本结点不应为根结点 */
				state->curr_status = MIME_S_TERM;
			} else if (state->curr_node->parent == state->root) {
				/* 说明根结点的一级子结点都结束,
				 * 则整封邮件分析完毕 */
				state->curr_status = MIME_S_TERM;
			} else {
				/* 说明本结点为根结点的二级或以上结点, 同时
				 * 说明本结点的父结点已经结束, 下一步需要找
				 * 出本结点的爷爷结点的分隔符
				 */

				/* 只有根结点 root 的父结点为 NULL */
				acl_assert(state->curr_node->parent);
				acl_assert(state->curr_node->parent->boundary);

				state->curr_node = state->curr_node->parent;
				state->curr_bound =
					STR(state->curr_node->parent->boundary);
				
				state->curr_status = MIME_S_MULTI_BOUND;
				state->curr_node->bound_ptr = NULL;
			}

			return n - 1;
		}

		acl_assert(state->curr_node != NULL);

		MIME_NODE *node = mime_node_new(state);

		node->header_begin = state->curr_off;
		if (state->curr_node->boundary != NULL) {
			acl_assert(state->curr_bound ==
				STR(state->curr_node->boundary));
			mime_node_add_child(state->curr_node, node);
		} else {
			acl_assert(state->curr_node->parent->boundary != NULL);
			acl_assert(state->curr_bound ==
				STR(state->curr_node->parent->boundary));
			mime_node_add_child(state->curr_node->parent, node);
		}

		state->curr_node = node;
		state->curr_status = MIME_S_HEAD;
		state->curr_node->last_ch = 0;
		state->curr_node->last_lf = 0;

		return n - 1;
	} else if (*s == '\r') {
		state->curr_node->last_cr_pos = state->curr_off;
		state->curr_node->last_ch = '\r';
		state->curr_off++;
		state->use_crlf = 1;
		/* 期待下一个字符为 '\n' */
		return n - 1;
	} else if (*s == '-') {
		state->curr_off++;
		if (state->curr_node->bound_term[0] == '-') {
			state->curr_node->bound_term[1] = '-';
			/* 期待下一个字符为 '\r' 或 '\n' */
			return n - 1;
		} else {
			/* 期待下一个字符为 '-' */
			state->curr_node->bound_term[0] = '-';
			return n - 1;
		}
	} else {
		/* XXX: 分隔符后非法字符 ? */

		/* 弹出父结点, 并开始分析属于该父结点的下一个结点 */

		state->curr_node = state->curr_node->parent;
		state->curr_off++;

		/* xxx */
		if (state->curr_node == NULL)
			state->curr_node = state->root;
		state->curr_status = MIME_S_HEAD;
		state->curr_node->last_ch = 0;
		state->curr_node->last_lf = 0;
		return n - 1;
	}
}

static int mime_state_multi_bound(MIME_STATE *state, const char *s, int n)
{
	MIME_NODE *node = state->curr_node;
	const unsigned char *cp, *end = (const unsigned char*) s + n;
	//const unsigned char *startn = NULL;

	acl_assert(state->curr_bound != NULL);
	acl_assert(node->parent != NULL);
	acl_assert(node->parent->boundary != NULL);

	const char *boundary = state->curr_bound;

	for (cp = (const unsigned char *) s; cp < end; cp++) {
		// 记录下 \r\n 的位置
		if (*cp == '\r')
			node->last_cr_pos = state->curr_off;
		else if (*cp == '\n')
			node->last_lf_pos = state->curr_off;

		state->curr_off++;
		if (node->bound_ptr != NULL) {
			if (*cp != *node->bound_ptr) {
				// 说明之前的匹配失效，需要重新匹配，
				// 但必须将之前匹配的字符拷贝
				node->bound_ptr = NULL;
			} else if (*++node->bound_ptr == 0) {
				// 说明完全匹配
				state->curr_status = MIME_S_MULTI_BOUND_CRLF;
				node->bound_ptr = NULL;
				cp++;
				break;
			}
		}

		if (!node->bound_ptr && *cp == *boundary) {
			node->bound_ptr = boundary + 1;

			/* 说明完全匹配 */
			if (*node->bound_ptr == 0) {
				state->curr_status = MIME_S_MULTI_BOUND_CRLF;
				node->bound_ptr = NULL;
				cp++;
				break;
			}
			//startn = cp;
		}
	}

	return (int) (n - ((const char*) cp - s));
}

static int mime_state_multi_bound_crlf(MIME_STATE *state, const char *s, int n)
{
	if (*s == '\n') {
		MIME_NODE *node = mime_node_new(state);

		node->last_lf_pos = state->curr_off;
		state->curr_off++;

		/* 设置 multipart 体结束位置，该位置包含了其所有子结点数据 */
		state->curr_node->bound_end = state->curr_off;

		/*
		state->curr_node->body_end = state->curr_node->bound_end
			- strlen(state->curr_bound) - 1;
		if (state->curr_node->last_ch == '\r')
			state->curr_node->body_end--;
		*/

		node->header_begin = state->curr_off;
		mime_node_add_child(state->curr_node->parent, node);
		state->curr_node = node;
		state->curr_status = MIME_S_HEAD;
		node->bound_ptr = NULL;
		node->last_ch = 0;
		node->last_lf = 0;
		return n - 1;
	} else if (*s == '\r') {
		state->curr_node->last_cr_pos = state->curr_off;
		state->curr_node->last_ch = '\r';
		state->curr_off++;
		state->use_crlf = 1;
		/* 期待下一个字符为 '\n' */
		return n - 1;
	} else {
		/* xxx */
		state->curr_off += n;
		return 0;
	}
}

static int mime_state_term(MIME_STATE *state, const char *s, int n)
{
	(void) s;
	state->curr_off += n;
	return 0;
}

static struct MIME_STATUS_MACHINE status_tab[] = {
	{ MIME_S_HEAD, mime_state_head },
	{ MIME_S_BODY, mime_state_body },
	{ MIME_S_BODY_BOUND_CRLF, mime_state_body_bound_crlf },
	{ MIME_S_MULTI_BOUND, mime_state_multi_bound },
	{ MIME_S_MULTI_BOUND_CRLF, mime_state_multi_bound_crlf },
	{ MIME_S_TERM, mime_state_term },
};

int mime_state_update(MIME_STATE *state, const char *ptr, int n)
{
	const char *s = ptr;
	int ret;

	while (n > 0) {
		ret = status_tab[state->curr_status].callback(state, s, n);
		if (state->curr_status == MIME_S_TERM)
			return 1;
		acl_assert(ret >= 0);
		if (ret == 0)
			break;
		s += n - ret;
		n = ret;
	}

	return 0;
}

#endif // !defined(ACL_MIME_DISABLE)
