From 8be354a6d5705344e43f2efc2121500e96165c7b Mon Sep 17 00:00:00 2001
From: Dan Kortschak <dan@kortschak.io>
Date: Wed, 15 Aug 2018 19:27:14 +0930
Subject: [PATCH] Port AMF3ReadInteger, AMF3ReadString, AMF3DC_AddProp and
 AMFProp_SetName

---
 rtmp/rtmp.go | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/rtmp/rtmp.go b/rtmp/rtmp.go
index 57192e63..16680f8d 100644
--- a/rtmp/rtmp.go
+++ b/rtmp/rtmp.go
@@ -3558,6 +3558,86 @@ func C_AMF_EncodeNamedBoolean(output *byte, outend *byte, strName *C.AVal, bVal
 	return C_AMF_EncodeBoolean(output, outend, bVal)
 }
 
+// void AMFProp_SetName(AMFObjectProperty *prop, AVal *name);
+// amf.c +318
+func C_AMFProp_SetName(prop *C.AMFObjectProperty, name *C.AVal) {
+	prop.p_name = *name
+}
+
+const (
+	AMF3_INTEGER_MAX = 268435455
+	AMF3_INTEGER_MIN = -268435456
+)
+
+// int AMF3ReadInteger(const char *data, int32_t *valp);
+// amf.c +426
+func C_AMF3ReadInteger(data *byte, valp *int32) int32 {
+	var i int
+	var val int32
+
+	for i <= 2 {
+		/* handle first 3 bytes */
+		if *indxBytePtr(unsafe.Pointer(data), i)&0x80 != 0 {
+			/* byte used */
+			val <<= 7                                                  /* shift up */
+			val |= int32(*indxBytePtr(unsafe.Pointer(data), i) & 0x7f) /* add bits */
+			i++
+		} else {
+			break
+		}
+	}
+
+	if i > 2 {
+		/* use 4th byte, all 8bits */
+		val <<= 8
+		val |= int32(*indxBytePtr(unsafe.Pointer(data), 3))
+
+		/* range check */
+		if val > AMF3_INTEGER_MAX {
+			val -= (1 << 29)
+		}
+	} else {
+		/* use 7bits of last unparsed byte (0xxxxxxx) */
+		val <<= 7
+		val |= int32(*indxBytePtr(unsafe.Pointer(data), i))
+	}
+
+	*valp = val
+
+	if i > 2 {
+		return 4
+	}
+	return int32(i + 1)
+}
+
+// int AMF3ReadString(const char *data, AVal *str);
+// amf.c +466
+func C_AMF3ReadString(data *byte, str *C.AVal) int32 {
+	var ref int32
+	// assert elided - we will get a panic if it's nil.
+
+	len := C_AMF3ReadInteger(data, &ref)
+	data = indxBytePtr(unsafe.Pointer(data), int(len))
+
+	if ref&0x1 == 0 {
+		/* reference: 0xxx */
+		// TODO(kortschak) Logging.
+		// refIndex := (ref >> 1)
+		// RTMP_Log(RTMP_LOGDEBUG,
+		// "%s, string reference, index: %d, not supported, ignoring!",
+		// __FUNCTION__, refIndex);
+		str.av_val = nil
+		str.av_len = 0
+		return len
+	} else {
+		nSize := (ref >> 1)
+		str.av_val = (*C.char)(unsafe.Pointer(data))
+		str.av_len = C.int(nSize)
+		return len + nSize
+	}
+	return len
+}
+
 // char* AMF_EncodeBoolean(char* output, char* outend, int bVal);
 // amf.c +260
 func C_AMF_EncodeBoolean(output *byte, outend *byte, bVal int) *byte {
@@ -3765,6 +3845,16 @@ func C_AMF_EncodeInt32(output *byte, outend *byte, nVal int32) *byte {
 	return (*byte)(incBytePtr(outputPtr, 4))
 }
 
+// void AMF3CD_AddProp(AMF3ClassDef *cd, AVal *prop);
+// amf.c +1298
+func AMF3CD_AddProp(cd *C.AMF3ClassDef, prop *C.AVal) {
+	if cd.cd_num&0x0f == 0 {
+		cd.cd_props = (*C.AVal)(realloc(unsafe.Pointer(cd.cd_props), int(uintptr(cd.cd_num+16)*unsafe.Sizeof(C.AVal{}))))
+	}
+	*(*C.AVal)(incPtr(unsafe.Pointer(cd.cd_props), int(cd.cd_num), int(unsafe.Sizeof(C.AVal{})))) = *prop
+	cd.cd_num++
+}
+
 func realloc(ptr unsafe.Pointer, size int) unsafe.Pointer {
 	dest := allocate(uintptr(size))
 	if ptr != nil {