From: Christopher Faulet <cfaulet@haproxy.com>
Date: Mon, 24 Feb 2020 10:41:59 +0000 (+0100)
Subject: MINOR: htx: Add a function to return a block at a specific offset
X-Git-Tag: v2.2-dev4~45
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1cdceb936521ca4dc06d4f57af909310ec374a5e;p=thirdparty%2Fhaproxy.git

MINOR: htx: Add a function to return a block at a specific offset

The htx_find_offset() function may be used to look for a block at a specific
offset in an HTX message, starting from the message head. A compound result is
returned, an htx_ret structure, with the found block and the position of the
offset in the block. If the offset is ouside of the HTX message, the returned
block is NULL.
---

diff --git a/include/common/htx.h b/include/common/htx.h
index 11caa59bff..9818a3f4da 100644
--- a/include/common/htx.h
+++ b/include/common/htx.h
@@ -230,6 +230,7 @@ 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_ret htx_find_offset(struct htx *htx, uint32_t offset);
 void htx_truncate(struct htx *htx, uint32_t offset);
 struct htx_ret htx_drain(struct htx *htx, uint32_t max);
 
diff --git a/src/htx.c b/src/htx.c
index 41eb47274e..1ee60dcbdd 100644
--- a/src/htx.c
+++ b/src/htx.c
@@ -391,6 +391,31 @@ struct htx_blk *htx_remove_blk(struct htx *htx, struct htx_blk *blk)
 	return blk;
 }
 
+/* Looks for the HTX block containing the offset <offset>, starting at the HTX
+ * message's head. The function returns an htx_ret with the found HTX block and
+ * the position inside this block where the offset is. If the offset <offset> is
+ * ouside of the HTX message, htx_ret.blk is set to NULL.
+ */
+struct htx_ret htx_find_offset(struct htx *htx, uint32_t offset)
+{
+	struct htx_blk *blk;
+	struct htx_ret htxret = { .blk = NULL, .ret = 0 };
+
+	if (offset >= htx->data)
+		return htxret;
+
+	for (blk = htx_get_head_blk(htx); blk && offset; blk = htx_get_next_blk(htx, blk)) {
+		uint32_t sz = htx_get_blksz(blk);
+
+		if (offset < sz)
+			break;
+		offset -= sz;
+	}
+	htxret.blk = blk;
+	htxret.ret = offset;
+	return htxret;
+}
+
 /* Removes all blocks after the one containing the offset <offset>. This last
  * one may be truncated if it is a DATA block.
  */