From d4d9491f3c0b19a044556f7fdc3e34d425d256f7 Mon Sep 17 00:00:00 2001
From: hyung-hwan <hyunghwan.chung@gmail.com>
Date: Sun, 4 Mar 2018 14:43:23 +0000
Subject: [PATCH] exported hcl_readchar() and hcl_unreadchar()

---
 lib/hcl.h  | 16 ++++++++++++++++
 lib/read.c | 19 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/lib/hcl.h b/lib/hcl.h
index 5de3098..dbde917 100644
--- a/lib/hcl.h
+++ b/lib/hcl.h
@@ -1497,6 +1497,7 @@ HCL_EXPORT hcl_oop_t hcl_read (
 	hcl_t*       hcl
 );
 
+
 HCL_EXPORT int hcl_print (
 	hcl_t*       hcl,
 	hcl_oop_t    obj
@@ -1513,6 +1514,21 @@ HCL_EXPORT int hcl_decode (
 	hcl_ooi_t         end
 );
 
+
+/* if you should read charcters from the input stream before hcl_read(), 
+ * you can call hcl_readchar() */
+HCL_EXPORT hcl_iolxc_t* hcl_readchar (
+	hcl_t* hcl
+);
+
+/* If you use hcl_readchar() to read the input stream, you may use 
+ * hcl_unreadchar() to put back characters read for hcl_readchar() 
+ * to return before reading the stream again. */
+HCL_EXPORT int hcl_unreadchar (
+	hcl_t*             hcl,
+	const hcl_iolxc_t* c
+);
+
 /* =========================================================================
  * SYNTAX ERROR HANDLING
  * ========================================================================= */
diff --git a/lib/read.c b/lib/read.c
index 893ef8f..0c47865 100644
--- a/lib/read.c
+++ b/lib/read.c
@@ -2402,3 +2402,22 @@ void hcl_detachio (hcl_t* hcl)
 		}
 	}
 }
+
+hcl_iolxc_t* hcl_readchar (hcl_t* hcl)
+{
+	int n = get_char(hcl);
+	if (n <= -1) return HCL_NULL;
+	return &hcl->c->lxc;
+}
+
+int hcl_unreadchar (hcl_t* hcl, const hcl_iolxc_t* c)
+{
+	if (hcl->c->nungots >= HCL_COUNTOF(hcl->c->ungot))
+	{
+		hcl_seterrnum (hcl, HCL_EBUFFULL);
+		return -1;
+	}
+
+	unget_char (hcl, c);
+	return 0;
+}