From b18ae2913234c154e0fc057d722088bc73aff608 Mon Sep 17 00:00:00 2001
From: Jake Lane <me@jakelane.me>
Date: Thu, 19 Jul 2018 16:56:41 +0930
Subject: [PATCH] rtmp: Implement afmEncodeInt16

---
 rtmp/rtmp.go | 63 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 53 insertions(+), 10 deletions(-)

diff --git a/rtmp/rtmp.go b/rtmp/rtmp.go
index 90954404..6850aa2c 100644
--- a/rtmp/rtmp.go
+++ b/rtmp/rtmp.go
@@ -509,16 +509,14 @@ func afmEncodeString(output *byte, outend *byte, bv *C.AVal) *byte {
 		*(*C.char)(outputPtr) = C.AMF_STRING
 		incBytePtr(outputPtr, 1)
 
-		// TODO Encode Int16
-		outputPtr = unsafe.Pointer(C.AMF_EncodeInt16((*C.char)(outputPtr),
-			(*C.char)(outendPtr), (C.short)(bv.av_len)))
+		outputPtr = unsafe.Pointer(afmEncodeInt16((*byte)(outputPtr),
+			(*byte)(outendPtr), (int16)(bv.av_len)))
 	} else {
 		*(*C.char)(outputPtr) = C.AMF_LONG_STRING
 		incBytePtr(outputPtr, 1)
 
-		// TODO Encode Int16
-		outputPtr = unsafe.Pointer(C.AMF_EncodeInt32((*C.char)(outputPtr),
-			(*C.char)(outendPtr), bv.av_len))
+		outputPtr = unsafe.Pointer(afmEncodeInt32((*byte)(outputPtr),
+			(*byte)(outendPtr), (int32)(bv.av_len)))
 	}
 	memmove(unsafe.Pointer(outputPtr), unsafe.Pointer(bv.av_val), uintptr(bv.av_len))
 	//C.memcpy(unsafe.Pointer(outputPtr), unsafe.Pointer(bv.av_val), (C.size_t)(bv.av_len))
@@ -527,6 +525,52 @@ func afmEncodeString(output *byte, outend *byte, bv *C.AVal) *byte {
 	return (*byte)(outputPtr)
 }
 
+// afmEncodeInt16 encodes a int16 into data
+func afmEncodeInt16(output *byte, outend *byte, nVal int16) *byte {
+	outputPtr := unsafe.Pointer(output)
+	outendPtr := unsafe.Pointer(outend)
+	if uintptr(outputPtr)+2 > uintptr(outendPtr) {
+		// length < 2
+		return nil
+	}
+
+	// Assign output[1]
+	second := (*byte)(incBytePtr(outputPtr, 1))
+	*second = (byte)(nVal & 0xff)
+
+	// Assign output[0]
+	*output = (byte)(nVal >> 8)
+
+	return (*byte)(incBytePtr(outputPtr, 2))
+}
+
+// afmEncodeInt32 encodes a int32 into data
+func afmEncodeInt32(output *byte, outend *byte, nVal int32) *byte {
+	outputPtr := unsafe.Pointer(output)
+	outendPtr := unsafe.Pointer(outend)
+	if uintptr(outputPtr)+4 > uintptr(outendPtr) {
+		// length < 4
+		return nil
+	}
+
+	// Assign output[3]
+	forth := (*byte)(incBytePtr(outputPtr, 3))
+	*forth = (byte)(nVal & 0xff)
+
+	// Assign output[2]
+	third := (*byte)(incBytePtr(outputPtr, 2))
+	*third = (byte)(nVal >> 8)
+
+	// Assign output[1]
+	second := (*byte)(incBytePtr(outputPtr, 1))
+	*second = (byte)(nVal >> 16)
+
+	// Assign output[0]
+	*output = (byte)(nVal >> 24)
+
+	return (*byte)(incBytePtr(outputPtr, 4))
+}
+
 // send packet version 1 - less C stuff
 func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 	var prevPacket *C.RTMPPacket
@@ -662,7 +706,7 @@ func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 	}
 
 	if t >= 0xffffff {
-		hptr = unsafe.Pointer(C.AMF_EncodeInt32((*C.char)(hptr), (*C.char)(hend), C.int(t)))
+		hptr = unsafe.Pointer(afmEncodeInt32((*byte)(hptr), (*byte)(hend), (int32)(t)))
 	}
 
 	nSize = int(packet.m_nBodySize)
@@ -739,9 +783,8 @@ func sendPacket(r *C.RTMP, packet *C.RTMPPacket, queue int) int {
 			}
 			if t >= 0xffffff {
 				extendedTimestamp := incBytePtr(header, 1+cSize)
-				// TODO: port this
-				C.AMF_EncodeInt32((*C.char)(extendedTimestamp),
-					(*C.char)(incBytePtr(extendedTimestamp, 4)), C.int(t))
+				afmEncodeInt32((*byte)(extendedTimestamp),
+					(*byte)(incBytePtr(extendedTimestamp, 4)), (int32)(t))
 			}
 		}
 	}