From d2c106b4db1ebece4df63268fd73a8ab789cb58a Mon Sep 17 00:00:00 2001
From: Denis Kenzior <denkenz@gmail.com>
Date: Thu, 6 Aug 2009 17:05:52 -0500
Subject: [PATCH] Be more lenient for PDU lines

---
 gatchat/gatsyntax.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/gatchat/gatsyntax.c b/gatchat/gatsyntax.c
index 7c5aadce..890d01d5 100644
--- a/gatchat/gatsyntax.c
+++ b/gatchat/gatsyntax.c
@@ -36,6 +36,8 @@ enum GSMV1_STATE_ {
 	GSMV1_STATE_GUESS_MULTILINE_RESPONSE,
 	GSMV1_STATE_MULTILINE_RESPONSE,
 	GSMV1_STATE_MULTILINE_TERMINATOR_CR,
+	GSMV1_STATE_PDU_CHECK_EXTRA_CR,
+	GSMV1_STATE_PDU_CHECK_EXTRA_LF,
 	GSMV1_STATE_PDU,
 	GSMV1_STATE_PDU_CR,
 	GSMV1_STATE_PROMPT,
@@ -47,7 +49,7 @@ static void gsmv1_hint(GAtSyntax *syntax, GAtSyntaxExpectHint hint)
 {
 	switch (hint) {
 	case G_AT_SYNTAX_EXPECT_PDU:
-		syntax->state = GSMV1_STATE_PDU;
+		syntax->state = GSMV1_STATE_PDU_CHECK_EXTRA_CR;
 		break;
 	case G_AT_SYNTAX_EXPECT_MULTILINE:
 		syntax->state = GSMV1_STATE_GUESS_MULTILINE_RESPONSE;
@@ -129,6 +131,27 @@ static GAtSyntaxResult gsmv1_feed(GAtSyntax *syntax,
 
 			goto out;
 
+		/* Some 27.007 compliant modems still get this wrong.  They
+		 * insert an extra CRLF between the command and he PDU,
+		 * in effect making them two separate lines.  We try to
+		 * handle this case gracefully
+		 */
+		case GSMV1_STATE_PDU_CHECK_EXTRA_CR:
+			if (byte == '\r')
+				syntax->state = GSMV1_STATE_PDU_CHECK_EXTRA_LF;
+			else
+				syntax->state = GSMV1_STATE_PDU;
+			break;
+
+		case GSMV1_STATE_PDU_CHECK_EXTRA_LF:
+			res = G_AT_SYNTAX_RESULT_UNRECOGNIZED;
+			syntax->state = GSMV1_STATE_PDU;
+
+			if (byte == '\n')
+				i += 1;
+			
+			goto out;
+
 		case GSMV1_STATE_PDU:
 			if (byte == '\r')
 				syntax->state = GSMV1_STATE_PDU_CR;