Scte35 creation

psi/doc.go

@@ -64,13 +64,12 @@ const (
 	CrcLen       uint16 = 4
 )
 
-// PSI interface represents operations available on all PSI
-type PSI interface {
-	PointerField() uint8
-	TableID() uint8
-	SectionSyntaxIndicator() bool
-	PrivateIndicator() bool
-	SectionLength() uint16
+// TableHeader struct represents operations available on all PSI
+type TableHeader struct {
+	TableID                uint8
+	SectionSyntaxIndicator bool
+	PrivateIndicator       bool
+	SectionLength          uint16
 }
 
 // PmtStreamType is used to represent elementary steam type inside a PMT

psi/psi.go

@@ -60,3 +60,54 @@ func sectionSyntaxIndicator(psi []byte) bool {
 func sectionLength(psi []byte) uint16 {
 	return uint16(psi[1]&3)<<8 | uint16(psi[2])
 }
+
+// NewPointerField will return a new pointer field with stuffing as raw bytes.
+// The pointer field specifies where the TableHeader should start.
+// Everything in between the pointer field and table header should
+// be bytes with the value 0xFF.
+func NewPointerField(size int) []byte {
+	data := make([]byte, size+1)
+	data[0] = byte(size)
+	for i := 1; i < size+1; i++ {
+		data[i] = 0xFF
+	}
+	return data
+}
+
+// PSIFromBytes returns the PSI struct from a byte slice
+func TableHeaderFromBytes(data []byte) TableHeader {
+	th := TableHeader{}
+
+	th.TableID = data[0]
+	th.SectionSyntaxIndicator = data[1]&0x80 != 0
+	th.PrivateIndicator = data[1]&0x40 != 0
+	th.SectionLength = uint16(data[1]&0x03 /* 0000 0011 */)<<8 | uint16(data[2])
+
+	return th
+}
+
+// Data returns the byte representation of the PSI struct.
+func (th TableHeader) Data() []byte {
+	data := make([]byte, 3)
+
+	data[0] = th.TableID
+	if th.SectionSyntaxIndicator {
+		data[1] |= 0x80
+	}
+	if th.PrivateIndicator {
+		data[1] |= 0x40
+	}
+
+	// set reserved bits to 11
+	data[1] |= 0x30 // 0011 0000
+
+	data[1] |= byte(th.SectionLength>>8) & 0x03 // 0000 0011
+	data[2] = byte(th.SectionLength)
+
+	return data
+}
+
+// NewPSI will create a PSI with default values of zero and false for everything
+func NewTableHeader() TableHeader {
+	return TableHeader{}
+}

psi/psi_test.go

@@ -0,0 +1,75 @@
+/*
+MIT License
+
+Copyright 2016 Comcast Cable Communications Management, LLC
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+package psi
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestDefaultPSIData(t *testing.T) {
+	th := NewTableHeader()
+	generated := th.Data()
+	target := []byte{0x00, 0x30, 0x00}
+	if !bytes.Equal(target, generated) {
+		t.Errorf("NewTableHeader does not produce expected Data. \nExpected: %X \n     Got: %X ", target, generated)
+	}
+}
+
+func TestPSIFromBytes(t *testing.T) {
+	target := []byte{0x04, 0xFF, 0xFF, 0xFF, 0xFF, 0x18, 0xB1, 0xFF}
+	th := TableHeaderFromBytes(target[5:])
+
+	if th.TableID != 0x18 {
+		t.Errorf("TableHeaderFromBytes does not produce expected TableID. \nExpected: %X \n     Got: %X ", 0x18, th.TableID)
+	}
+	if th.SectionLength != 0x1FF {
+		t.Errorf("TableHeaderFromBytes does not produce expected SectionLength. \nExpected: %X \n     Got: %X ", 0x1FF, th.SectionLength)
+	}
+	if th.PrivateIndicator {
+		t.Errorf("TableHeaderFromBytes does not produce expected PrivateIndicator. \nExpected: %t \n     Got: %t ", true, th.PrivateIndicator)
+	}
+	if !th.SectionSyntaxIndicator {
+		t.Errorf("TableHeaderFromBytes does not produce expected SectionSyntaxIndicator. \nExpected: %t \n     Got: %t ", false, th.SectionSyntaxIndicator)
+	}
+	generated := append(NewPointerField(4), th.Data()...)
+	if !bytes.Equal(target, generated) {
+		t.Errorf("Data does not produce same bytes. \nExpected: %X \n     Got: %X ", target, generated)
+	}
+}
+
+func TestPSICreate(t *testing.T) {
+	target := []byte{0x05, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x18, 0x70, 0xFF}
+	th := NewTableHeader()
+
+	th.TableID = 0x18
+	th.SectionLength = 0x0FF
+	th.PrivateIndicator = true
+	th.SectionSyntaxIndicator = false
+	generated := append(NewPointerField(5), th.Data()...)
+
+	if !bytes.Equal(target, generated) {
+		t.Errorf("Pointer field and TableHeader do not produce expected bytes. \nExpected: %X \n     Got: %X ", target, generated)
+	}
+}