diff --git a/include/common/htx.h b/include/common/htx.h
new file mode 100644
index 0000000..93031cd
--- /dev/null
+++ b/include/common/htx.h
@@ -0,0 +1,817 @@
+/*
+ * include/common/htx.h
+ * This file defines everything related to the internal HTTP messages.
+ *
+ * Copyright (C) 2018 HAProxy Technologies, Christopher Faulet <cfaulet@haproxy.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _COMMON_HTX_H
+#define _COMMON_HTX_H
+
+#include <stdio.h>
+#include <common/buf.h>
+#include <common/config.h>
+#include <common/ist.h>
+#include <common/http.h>
+#include <common/http-hdr.h>
+#include <common/standard.h>
+
+/*
+ * The internal representation of an HTTP message is a contiguous array
+ * containing both the blocks (htx_blk) and their contents. Blocks are stored
+ * starting from the end of the array while their contents are stored at the
+ * beginning.
+ *
+ * As data are sent to the peer, blocks and contents are released at the
+ * edges. This free space is reused when no more space left. So blocks and
+ * contents may wrap, not necessarily the same time.
+ *
+ * An HTTP block is as well a header as a body part or a trailer part. For all
+ * these types of block, a content is attached to the block. It can also be a
+ * mark, like the end-of-headers or end-of-message. For these blocks, there is
+ * no content but it count for a byte. It is important to not skip it when data
+ * are forwarded. An HTTP block is composed of 2 fields:
+ *
+ *     - .info : It a 32 bits field containing the block's type on 4 bits
+ *               followed by content' length. See below for details.
+ *
+ *     - .addr : The content's address, if any, relatively to the beginning the
+ *               array used to store the HTTP message itself.
+ *
+ * htx_blk.info representation:
+ *
+ *   0b 0000 0000 0000 0000 0000 0000 0000 0000
+ *      ---- ------------------------ ---------
+ *      type     value (1 MB max)     name length (header)
+ *           ----------------------------------
+ *                data length (256 MB max)
+ *    (body, method, path, version, status, reason, trailers)
+ *
+ *   types:
+ *     - 0000 = request  start-line
+ *     - 0001 = response start-line
+ *     - 0010 = header
+ *     - 0011 = pseudo-header ou "special" header
+ *     - 0100 = end-of-headers
+ *     - 0101 = data
+ *     - 0110 = end-of-data
+ *     - 0111 = trailer
+ *     - 1000 = end-of-message
+ *       ...
+ *     - 1101 = out-of-band
+ *     - 1110 = error
+ *     - 1111 = unused
+ *
+ */
+
+/*HTX start-line flags */
+#define HTX_SL_F_NONE          0x00000000
+#define HTX_SL_F_IS_RESP       0x00000001 /* It is the response start-line (unset means the request one) */
+#define HTX_SL_F_XFER_LEN      0x00000002 /* The message xfer size can be dertermined */
+#define HTX_SL_F_XFER_ENC      0x00000004 /* The transfer-encoding header was found in message */
+#define HTX_SL_F_CLEN          0x00000008 /* The content-length header was found in message */
+#define HTX_SL_F_CHNK          0x00000010 /* The message payload is chunked */
+#define HTX_SL_F_VER_11        0x00000020 /* The message indicates version 1.1 or above */
+#define HTX_SL_F_BODYLESS      0x00000040 /* The message has no body (content-length = 0) */
+
+/* HTX flags */
+#define HTX_FL_NONE              0x00000000
+#define HTX_FL_PARSING_ERROR     0x00000001
+
+
+/* Pseudo header types (max 255). */
+enum htx_phdr_type {
+	HTX_PHDR_UNKNOWN =  0,
+	HTX_PHDR_SIZE,
+};
+
+/* HTTP block's type (max 15). */
+enum htx_blk_type {
+	HTX_BLK_REQ_SL =  0, /* Request start-line */
+	HTX_BLK_RES_SL =  1, /* Response start-line */
+	HTX_BLK_HDR    =  2, /* header name/value block */
+	HTX_BLK_PHDR   =  3, /* pseudo header block */
+	HTX_BLK_EOH    =  4, /* end-of-headers block */
+	HTX_BLK_DATA   =  5, /* data block */
+	HTX_BLK_EOD    =  6, /* end-of-data block */
+	HTX_BLK_TLR    =  7, /* trailer name/value block */
+	HTX_BLK_EOM    =  8, /* end-of-message block */
+	/* 9 .. 13 unused */
+	HTX_BLK_OOB    = 14, /* Out of band block, don't alter the parser */
+	HTX_BLK_UNUSED = 15, /* unused/removed block */
+};
+
+/* One HTTP block descriptor */
+struct htx_blk {
+	uint32_t addr; /* relative storage address of a data block */
+	uint32_t info; /* information about data stored */
+};
+
+struct htx_ret {
+	int32_t ret;
+	struct htx_blk *blk;
+};
+
+struct htx_sl {
+	unsigned int flags; /* HTX_SL_F_* */
+	union {
+		struct {
+			enum http_meth_t meth;   /* method */
+		} req;
+		struct {
+			uint16_t         status; /* status code */
+		} res;
+	} info;
+
+	/* XXX 2 bytes unused */
+
+	unsigned int len[3]; /* length of differnt parts of the start-line */
+	char         l[0];
+};
+
+/* Internal representation of an HTTP message */
+struct htx {
+	uint32_t size;   /* the array size, in bytes, used to store the HTTP message itself */
+	uint32_t data;   /* the data size, in bytes. To known to total size used by all allocated
+			  * blocks (blocks and their contents), you need to add size used by blocks,
+			  * i.e. [ used * sizeof(struct htx_blk *) ] */
+
+	uint32_t used;   /* number of blocks in use */
+	uint32_t tail;   /* last inserted block */
+	uint32_t front;  /* block's position of the first content before the blocks table */
+	uint32_t wrap;   /* the position were the blocks table wraps, if any */
+
+	uint64_t extra;  /* known bytes amount remaining to receive */
+	uint32_t flags;  /* HTX_FL_* */
+
+	int32_t sl_off; /* Offset of the start-line of the HTTP message relatively to the beginning the
+			   data block. -1 if unset */
+
+	struct htx_blk blocks[0]; /* Blocks representing the HTTP message itself */
+};
+
+
+extern struct htx htx_empty;
+
+struct htx_blk *htx_defrag(struct htx *htx, struct htx_blk *blk);
+struct htx_blk *htx_add_blk(struct htx *htx, enum htx_blk_type type, uint32_t blksz);
+struct htx_blk *htx_remove_blk(struct htx *htx, struct htx_blk *blk);
+
+struct htx_blk *htx_replace_blk_value(struct htx *htx, struct htx_blk *blk,
+				      const struct ist old, const struct ist new);
+struct htx_ret htx_xfer_blks(struct htx *dst, struct htx *src, uint32_t count,
+			     enum htx_blk_type mark);
+
+struct htx_sl *htx_add_stline(struct htx *htx, enum htx_blk_type type, unsigned int flags,
+			      const struct ist p1, const struct ist p2, const struct ist p3);
+struct htx_sl *htx_replace_stline(struct htx *htx, struct htx_blk *blk, const struct ist p1,
+				  const struct ist p2, const struct ist p3);
+
+struct htx_blk *htx_replace_header(struct htx *htx, struct htx_blk *blk,
+				   const struct ist name, const struct ist value);
+
+struct htx_blk *htx_add_header(struct htx *htx, const struct ist name, const struct ist value);
+struct htx_blk *htx_add_all_headers(struct htx *htx, const struct http_hdr *hdrs);
+struct htx_blk *htx_add_pseudo_header(struct htx *htx,  enum htx_phdr_type phdr, const struct ist value);
+struct htx_blk *htx_add_endof(struct htx *htx, enum htx_blk_type type);
+struct htx_blk *htx_add_data(struct htx *htx, const struct ist data);
+struct htx_blk *htx_add_trailer(struct htx *htx, const struct ist tlr);
+struct htx_blk *htx_add_oob(struct htx *htx, const struct ist oob);
+struct htx_blk *htx_add_data_before(struct htx *htx, const struct htx_blk *ref, const struct ist data);
+
+int htx_reqline_to_h1(const struct htx_sl *sl, struct buffer *chk);
+int htx_stline_to_h1(const struct htx_sl *sl, struct buffer *chk);
+int htx_hdr_to_h1(const struct ist n, const struct ist v, struct buffer *chk);
+int htx_data_to_h1(const struct ist data, struct buffer *chk, int chunked);
+int htx_trailer_to_h1(const struct ist tlr, struct buffer *chk);
+
+/* Functions and macros to get parts of the start-line or legnth of these
+ * parts
+ */
+#define HTX_SL_LEN(sl) ((sl)->len[0] + (sl)->len[1] + (sl)->len[2])
+
+#define HTX_SL_P1_LEN(sl) ((sl)->len[0])
+#define HTX_SL_P2_LEN(sl) ((sl)->len[1])
+#define HTX_SL_P3_LEN(sl) ((sl)->len[2])
+#define HTX_SL_P1_PTR(sl) ((sl)->l)
+#define HTX_SL_P2_PTR(sl) (HTX_SL_P1_PTR(sl) + HTX_SL_P1_LEN(sl))
+#define HTX_SL_P3_PTR(sl) (HTX_SL_P2_PTR(sl) + HTX_SL_P2_LEN(sl))
+
+#define HTX_SL_REQ_MLEN(sl) HTX_SL_P1_LEN(sl)
+#define HTX_SL_REQ_ULEN(sl) HTX_SL_P2_LEN(sl)
+#define HTX_SL_REQ_VLEN(sl) HTX_SL_P3_LEN(sl)
+#define HTX_SL_REQ_MPTR(sl) HTX_SL_P1_PTR(sl)
+#define HTX_SL_REQ_UPTR(sl) HTX_SL_P2_PTR(sl)
+#define HTX_SL_REQ_VPTR(sl) HTX_SL_P3_PTR(sl)
+
+#define HTX_SL_RES_VLEN(sl) HTX_SL_P1_LEN(sl)
+#define HTX_SL_RES_CLEN(sl) HTX_SL_P2_LEN(sl)
+#define HTX_SL_RES_RLEN(sl) HTX_SL_P3_LEN(sl)
+#define HTX_SL_RES_VPTR(sl) HTX_SL_P1_PTR(sl)
+#define HTX_SL_RES_CPTR(sl) HTX_SL_P2_PTR(sl)
+#define HTX_SL_RES_RPTR(sl) HTX_SL_P3_PTR(sl)
+
+static inline const struct ist htx_sl_p1(const struct htx_sl *sl)
+{
+	return ist2(HTX_SL_P1_PTR(sl), HTX_SL_P1_LEN(sl));
+}
+
+static inline const struct ist htx_sl_p2(const struct htx_sl *sl)
+{
+	return ist2(HTX_SL_P2_PTR(sl), HTX_SL_P2_LEN(sl));
+}
+
+static inline const struct ist htx_sl_p3(const struct htx_sl *sl)
+{
+	return ist2(HTX_SL_P3_PTR(sl), HTX_SL_P3_LEN(sl));
+}
+
+static inline const struct ist htx_sl_req_meth(const struct htx_sl *sl)
+{
+	return htx_sl_p1(sl);
+}
+
+static inline const struct ist htx_sl_req_uri(const struct htx_sl *sl)
+{
+	return htx_sl_p2(sl);
+}
+
+static inline const struct ist htx_sl_req_vsn(const struct htx_sl *sl)
+{
+	return htx_sl_p3(sl);
+}
+
+
+static inline const struct ist htx_sl_res_vsn(const struct htx_sl *sl)
+{
+	return htx_sl_p1(sl);
+}
+
+static inline const struct ist htx_sl_res_code(const struct htx_sl *sl)
+{
+	return htx_sl_p2(sl);
+}
+
+static inline const struct ist htx_sl_res_reason(const struct htx_sl *sl)
+{
+	return htx_sl_p3(sl);
+}
+
+/* Returns the HTX start-line if set, otherwise it returns NULL. */
+static inline struct htx_sl *htx_get_stline(struct htx *htx)
+{
+	struct htx_sl *sl = NULL;
+
+	if (htx->sl_off != -1)
+		sl = ((void *)htx->blocks + htx->sl_off);
+
+	return sl;
+}
+
+/* Returns the array index of a block given its position <pos> */
+static inline uint32_t htx_pos_to_idx(const struct htx *htx, uint32_t pos)
+{
+	return ((htx->size / sizeof(htx->blocks[0])) - pos - 1);
+}
+
+/* Returns the position of the block <blk> */
+static inline uint32_t htx_get_blk_pos(const struct htx *htx, const struct htx_blk *blk)
+{
+	return (htx->blocks + (htx->size / sizeof(htx->blocks[0])) - blk - 1);
+}
+
+/* Returns the block at the position <pos> */
+static inline struct htx_blk *htx_get_blk(const struct htx *htx, uint32_t pos)
+{
+	return ((struct htx_blk *)(htx->blocks) + htx_pos_to_idx(htx, pos));
+}
+
+/* Returns the type of the block <blk> */
+static inline enum htx_blk_type htx_get_blk_type(const struct htx_blk *blk)
+{
+	return (blk->info >> 28);
+}
+
+/* Returns the pseudo-header type of the block <blk>. If it's not a
+ * pseudo-header, HTX_PHDR_UNKNOWN is returned.
+ */
+static inline enum htx_phdr_type htx_get_blk_phdr(const struct htx_blk *blk)
+{
+	enum htx_blk_type type = htx_get_blk_type(blk);
+	enum htx_phdr_type phdr;
+
+	switch (type) {
+		case HTX_BLK_PHDR:
+			phdr = (blk->info & 0xff);
+			return phdr;
+
+		default:
+			/* Not a pseudo-header */
+			return HTX_PHDR_UNKNOWN;
+	}
+}
+
+/* Returns the size of the block <blk>, depending of its type */
+static inline uint32_t htx_get_blksz(const struct htx_blk *blk)
+{
+	enum htx_blk_type type = htx_get_blk_type(blk);
+
+	switch (type) {
+		case HTX_BLK_HDR:
+			/*       name.length       +        value.length        */
+			return ((blk->info & 0xff) + ((blk->info >> 8) & 0xfffff));
+		case HTX_BLK_PHDR:
+			/*          value.length          */
+			return ((blk->info >> 8) & 0xfffff);
+		default:
+			/*         value.length      */
+			return (blk->info & 0xfffffff);
+	}
+}
+
+/* Returns the position of the oldest entry (head).
+ *
+ * An signed 32-bits integer is returned to handle -1 case. Blocks position are
+ * store on unsigned 32-bits integer, but it is impossible to have so much
+ * blocks to overflow a 32-bits signed integer !
+ */
+static inline int32_t htx_get_head(const struct htx *htx)
+{
+	if (!htx->used)
+		return -1;
+
+	return (((htx->tail + 1U < htx->used) ? htx->wrap : 0) + htx->tail + 1U - htx->used);
+}
+
+/* Returns the oldest HTX block (head) if the HTX message is not
+ * empty. Otherwise it returns NULL.
+ */
+static inline struct htx_blk *htx_get_head_blk(const struct htx *htx)
+{
+	int32_t head = htx_get_head(htx);
+
+	return ((head == -1) ? NULL : htx_get_blk(htx, head));
+}
+
+/* Returns the type of the oldest HTX block (head) if the HTX message is not
+ * empty. Otherwise it returns HTX_BLK_UNUSED.
+ */
+static inline enum htx_blk_type htx_get_head_type(const struct htx *htx)
+{
+	struct htx_blk *blk = htx_get_head_blk(htx);
+
+	return (blk ? htx_get_blk_type(blk) : HTX_BLK_UNUSED);
+}
+
+/* Returns the position of the newest entry (tail).
+ *
+ * An signed 32-bits integer is returned to handle -1 case. Blocks position are
+ * store on unsigned 32-bits integer, but it is impossible to have so much
+ * blocks to overflow a 32-bits signed integer !
+ */
+static inline int32_t htx_get_tail(const struct htx *htx)
+{
+	return (htx->used ? htx->tail : -1);
+}
+
+/* Returns the newest HTX block (tail) if the HTX message is not
+ * empty. Otherwise it returns NULL.
+ */
+static inline struct htx_blk *htx_get_tail_blk(const struct htx *htx)
+{
+	int32_t tail = htx_get_tail(htx);
+
+	return ((tail == -1) ? NULL : htx_get_blk(htx, tail));
+}
+
+/* Returns the type of the newest HTX block (tail) if the HTX message is not
+ * empty. Otherwise it returns HTX_BLK_UNUSED.
+ */
+static inline enum htx_blk_type htx_get_tail_type(const struct htx *htx)
+{
+	struct htx_blk *blk = htx_get_tail_blk(htx);
+
+	return (blk ? htx_get_blk_type(blk) : HTX_BLK_UNUSED);
+}
+
+/* Returns the position of block immediately before the one pointed by <pos>. If
+ * the message is empty or if <pos> is the position of the head, -1 returned.
+ *
+ * An signed 32-bits integer is returned to handle -1 case. Blocks position are
+ * store on unsigned 32-bits integer, but it is impossible to have so much
+ * blocks to overflow a 32-bits signed integer !
+ */
+static inline int32_t htx_get_prev(const struct htx *htx, uint32_t pos)
+{
+	int32_t head;
+
+	head = htx_get_head(htx);
+	if (head == -1 || pos == head)
+		return -1;
+	if (!pos)
+		return (htx->wrap - 1);
+	return (pos - 1);
+}
+
+/* Returns the HTX block before <blk> in the HTX message <htx>. If <blk> is the
+ * head, NULL returned.
+ */
+static inline struct htx_blk *htx_get_prev_blk(const struct htx *htx,
+					       const struct htx_blk *blk)
+{
+	int32_t pos;
+
+	pos = htx_get_prev(htx, htx_get_blk_pos(htx, blk));
+	return ((pos == -1) ? NULL : htx_get_blk(htx, pos));
+}
+
+/* Returns the position of block immediately after the one pointed by <pos>. If
+ * the message is empty or if <pos> is the position of the tail, -1 returned.
+ *
+ * An signed 32-bits integer is returned to handle -1 case. Blocks position are
+ * store on unsigned 32-bits integer, but it is impossible to have so much
+ * blocks to overflow a 32-bits signed integer !
+ */
+static inline int32_t htx_get_next(const struct htx *htx, uint32_t pos)
+{
+	if (!htx->used)
+		return -1;
+
+	if (pos == htx->tail)
+		return -1;
+	pos++;
+	if (pos >= htx->wrap)
+		pos = 0;
+	return pos;
+
+}
+
+/* Returns the HTX block after <blk> in the HTX message <htx>. If <blk> is the
+ * tail, NULL returned.
+ */
+static inline struct htx_blk *htx_get_next_blk(const struct htx *htx,
+					       const struct htx_blk *blk)
+{
+	int32_t pos;
+
+	pos = htx_get_next(htx, htx_get_blk_pos(htx, blk));
+	return ((pos == -1) ? NULL : htx_get_blk(htx, pos));
+}
+
+static inline int32_t htx_find_front(const struct htx *htx)
+{
+	int32_t  front, pos;
+	uint32_t addr = 0;
+
+	if (!htx->used)
+		return -1;
+
+	front = -1;
+	for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+		struct htx_blk   *blk  = htx_get_blk(htx, pos);
+		enum htx_blk_type type = htx_get_blk_type(blk);
+
+		if (type != HTX_BLK_UNUSED && blk->addr >= addr) {
+			front = pos;
+			addr  = blk->addr;
+		}
+	}
+
+	return front;
+}
+
+/* Returns the HTX block containing data with the <offset>, relatively to the
+ * beginning of the HTX message <htx>. It returns an htx_ret. if the HTX block is
+ * not found, htx_ret.blk is set to NULL. Otherwise, it points to the right HTX
+ * block and htx_ret.ret is set to the remaining offset inside the block.
+ */
+static inline struct htx_ret htx_find_blk(const struct htx *htx, uint32_t offset)
+{
+	int32_t pos;
+
+	for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+		struct htx_blk *blk = htx_get_blk(htx, pos);
+		uint32_t sz = htx_get_blksz(blk);
+
+		if (offset < sz)
+			return (struct htx_ret){ .blk = blk, .ret = offset };
+		offset -= sz;
+	}
+
+	return (struct htx_ret){ .blk = NULL };
+}
+/* Changes the size of the value. It is the caller responsibility to change the
+ * value itself, make sure there is enough space and update allocated value.
+ */
+static inline void htx_set_blk_value_len(struct htx_blk *blk, uint32_t vlen)
+{
+	enum htx_blk_type type = htx_get_blk_type(blk);
+
+	switch (type) {
+		case HTX_BLK_HDR:
+		case HTX_BLK_PHDR:
+			blk->info = (type << 28) + (vlen << 8) + (blk->info & 0xff);
+			break;
+		case HTX_BLK_REQ_SL:
+		case HTX_BLK_RES_SL:
+		case HTX_BLK_DATA:
+		case HTX_BLK_TLR:
+		case HTX_BLK_OOB:
+			blk->info = (type << 28) + vlen;
+			break;
+		default:
+			/* Unexpected case */
+			break;
+	}
+}
+
+/* Returns the data pointer of the block <blk> */
+static inline void *htx_get_blk_ptr(const struct htx *htx, const struct htx_blk *blk)
+{
+	return ((void *)htx->blocks + blk->addr);
+}
+
+/* Returns the name of the block <blk>, only if it is a header. Otherwise it
+ * returns an empty name.
+ */
+static inline struct ist htx_get_blk_name(const struct htx *htx, const struct htx_blk *blk)
+{
+	enum htx_blk_type type = htx_get_blk_type(blk);
+	struct ist ret;
+
+	switch (type) {
+		case HTX_BLK_HDR:
+			ret.ptr = htx_get_blk_ptr(htx, blk);
+			ret.len = blk->info & 0xff;
+			break;
+
+		default:
+			return ist("");
+	}
+	return ret;
+}
+
+
+/* Returns the value of the block <blk>, depending on its type. If there is no
+ * value, an empty one is retruned.
+ */
+static inline struct ist htx_get_blk_value(const struct htx *htx, const struct htx_blk *blk)
+{
+	enum htx_blk_type type = htx_get_blk_type(blk);
+	struct ist ret;
+
+	switch (type) {
+		case HTX_BLK_HDR:
+			ret.ptr = htx_get_blk_ptr(htx, blk) + (blk->info & 0xff);
+			ret.len = (blk->info >> 8) & 0xfffff;
+			break;
+
+		case HTX_BLK_PHDR:
+			ret.ptr = htx_get_blk_ptr(htx, blk);
+			ret.len = (blk->info >> 8) & 0xfffff;
+			break;
+
+		case HTX_BLK_REQ_SL:
+		case HTX_BLK_RES_SL:
+		case HTX_BLK_DATA:
+		case HTX_BLK_TLR:
+		case HTX_BLK_OOB:
+			ret.ptr = htx_get_blk_ptr(htx, blk);
+			ret.len = blk->info & 0xfffffff;
+			break;
+
+		default:
+			return ist("");
+	}
+	return ret;
+}
+
+/* Removes <n> bytes from the beginning of DATA block <blk>. The block's start
+ * address and its length are adjusted, and the htx's total data count is
+ * updated. This is used to mark that part of some data were transfered
+ * from a DATA block without removing this DATA block. No sanity check is
+ * performed, the caller is reponsible for doing this exclusively on DATA
+ * blocks, and never removing more than the block's size.
+ */
+static inline void htx_cut_data_blk(struct htx *htx, struct htx_blk *blk, uint32_t n)
+{
+	blk->addr += n;
+	blk->info -= n;
+	htx->data -= n;
+}
+
+/* Returns the space used by metadata in <htx>. */
+static inline uint32_t htx_meta_space(const struct htx *htx)
+{
+	return (htx->used * sizeof(htx->blocks[0]));
+}
+
+/* Returns the space used (data + metadata) in <htx> */
+static inline uint32_t htx_used_space(const struct htx *htx)
+{
+	return (htx->data + htx_meta_space(htx));
+}
+
+/* Returns the free space in <htx> */
+static inline uint32_t htx_free_space(const struct htx *htx)
+{
+	return (htx->size - htx_used_space(htx));
+}
+
+/* Returns the maximum size available to store some data in <htx> if a new block
+ * is reserved.
+ */
+static inline uint32_t htx_free_data_space(const struct htx *htx)
+{
+	uint32_t free = htx_free_space(htx);
+
+	if (free < sizeof(htx->blocks[0]))
+		return 0;
+	return (free - sizeof(htx->blocks[0]));
+}
+
+/* Returns 1 if the message has less than 1/4 of its capacity free, otherwise 0 */
+static inline int htx_almost_full(const struct htx *htx)
+{
+	if (!htx->size || htx_free_space(htx) < htx->size / 4)
+		return 1;
+	return 0;
+}
+
+static inline void htx_reset(struct htx *htx)
+{
+	htx->data = htx->used = htx->tail = htx->wrap  = htx->front = 0;
+	htx->extra = 0;
+	htx->flags = HTX_FL_NONE;
+	htx->sl_off = -1;
+}
+
+/* returns the available room for raw data in buffer <buf> once HTX overhead is
+ * taken into account (one HTX header and two blocks). The purpose is to figure
+ * the optimal fill length to avoid copies.
+ */
+static inline size_t buf_room_for_htx_data(const struct buffer *buf)
+{
+	size_t room;
+
+	room = b_room(buf);
+	if (room <= sizeof(struct htx) + 2 * sizeof(struct htx_blk))
+		room = 0;
+	else
+		room -= sizeof(struct htx) + 2 * sizeof(struct htx_blk);
+
+	return room;
+}
+
+
+/* Returns an HTX message using the buffer <buf>. Unlike htx_from_buf(), this
+ * function does not update to the buffer. */
+static inline struct htx *htxbuf(const struct buffer *buf)
+{
+	struct htx *htx;
+
+	if (b_is_null(buf))
+		return &htx_empty;
+	htx = ((struct htx *)(buf->area));
+	if (!b_data(buf)) {
+		htx->size = buf->size - sizeof(*htx);
+		htx_reset(htx);
+	}
+	return htx;
+}
+
+/* Returns an HTX message using the buffer <buf>. <buf> is updated to appear as
+ * full. It is the caller responsibility to call htx_to_buf() when it finish to
+ * manipulate the HTX message to update <buf> accordingly.
+ *
+ * If the caller can call htxbuf() function to avoir any update of the
+ * buffer.
+ */
+static inline struct htx *htx_from_buf(struct buffer *buf)
+{
+	struct htx *htx = htxbuf(buf);
+
+	b_set_data(buf, b_size(buf));
+	return htx;
+}
+
+/* Upate <buf> accordingly to the HTX message <htx> */
+static inline void htx_to_buf(struct htx *htx, struct buffer *buf)
+{
+	if (!htx->used) {
+		htx_reset(htx);
+		b_set_data(buf, 0);
+	}
+	else
+		b_set_data(buf, b_size(buf));
+}
+
+/* Returns 1 if the message is empty, otherwise it returns 0. */
+static inline int htx_is_empty(const struct htx *htx)
+{
+	return (!htx || !htx->used);
+}
+
+/* Returns 1 if the message is not empty, otherwise it returns 0. */
+static inline int htx_is_not_empty(const struct htx *htx)
+{
+	return (htx && htx->used);
+}
+
+/* For debugging purpose */
+static inline const char *htx_blk_type_str(enum htx_blk_type type)
+{
+	switch (type) {
+		case HTX_BLK_REQ_SL: return "HTX_BLK_REQ_SL";
+		case HTX_BLK_RES_SL: return "HTX_BLK_RES_SL";
+		case HTX_BLK_HDR:    return "HTX_BLK_HDR";
+		case HTX_BLK_PHDR:   return "HTX_BLK_PHDR";
+		case HTX_BLK_EOH:    return "HTX_BLK_EOH";
+		case HTX_BLK_DATA:   return "HTX_BLK_DATA";
+		case HTX_BLK_EOD:    return "HTX_BLK_EOD";
+		case HTX_BLK_TLR:    return "HTX_BLK_TLR";
+		case HTX_BLK_EOM:    return "HTX_BLK_EOM";
+		case HTX_BLK_OOB:    return "HTX_BLK_OOB";
+		case HTX_BLK_UNUSED: return "HTX_BLK_UNUSED";
+		default:             return "HTX_BLK_???";
+	};
+}
+
+static inline const char *htx_blk_phdr_str(enum htx_phdr_type phdr)
+{
+	switch (phdr) {
+		case HTX_PHDR_UNKNOWN: return "HTX_PHDR_UNKNOWN";
+		default:               return "HTX_PHDR_???";
+	}
+}
+
+static inline void htx_dump(struct htx *htx)
+{
+	int32_t pos;
+
+	fprintf(stderr, "htx:%p [ size=%u - data=%u - used=%u - wrap=%s - extra=%llu]\n",
+		htx, htx->size, htx->data, htx->used,
+		(!htx->used || htx->tail+1 == htx->wrap) ? "NO" : "YES",
+		(unsigned long long)htx->extra);
+	fprintf(stderr, "\thead=%d - tail=%u - front=%u - wrap=%u\n",
+		htx_get_head(htx), htx->tail, htx->front, htx->wrap);
+
+	for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+		struct htx_sl     *sl;
+		struct htx_blk    *blk  = htx_get_blk(htx, pos);
+		enum htx_blk_type  type = htx_get_blk_type(blk);
+		enum htx_phdr_type phdr = htx_get_blk_phdr(blk);
+		uint32_t           sz   = htx_get_blksz(blk);
+		struct ist         n, v;
+
+		n = htx_get_blk_name(htx, blk);
+		v = htx_get_blk_value(htx, blk);
+
+		if (type == HTX_BLK_REQ_SL || type == HTX_BLK_RES_SL) {
+			sl = htx_get_blk_ptr(htx, blk);
+			fprintf(stderr, "\t\t[%u] type=%-17s - size=%-6u - addr=%-6u\t%.*s %.*s %.*s\n",
+				pos, htx_blk_type_str(type), sz, blk->addr,
+				HTX_SL_P1_LEN(sl), HTX_SL_P1_PTR(sl),
+				HTX_SL_P2_LEN(sl), HTX_SL_P2_PTR(sl),
+				HTX_SL_P3_LEN(sl), HTX_SL_P3_PTR(sl));
+		}
+		else if (type == HTX_BLK_HDR)
+			fprintf(stderr, "\t\t[%u] type=%-17s - size=%-6u - addr=%-6u\t%.*s: %.*s\n",
+				pos, htx_blk_type_str(type), sz, blk->addr,
+				(int)n.len, n.ptr,
+				(int)v.len, v.ptr);
+
+		else if (type == HTX_BLK_PHDR)
+			fprintf(stderr, "\t\t[%u] type=%-17s - size=%-6u - addr=%-6u\t%.*s\n",
+				pos, htx_blk_phdr_str(phdr), sz, blk->addr,
+				(int)v.len, v.ptr);
+		else
+			fprintf(stderr, "\t\t[%u] type=%-17s - size=%-6u - addr=%-6u%s\n",
+				pos, htx_blk_type_str(type), sz, blk->addr,
+				(!v.len ? "\t<empty>" : ""));
+	}
+	fprintf(stderr, "\n");
+}
+
+#endif /* _COMMON_HTX_H */
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ */