From 67be7684dcb3ed461a2c4630a1c722957f06963c Mon Sep 17 00:00:00 2001
From: Rob Watson <rob@netflux.io>
Date: Mon, 25 Jan 2021 09:03:24 +0100
Subject: [PATCH] Read some bytes

---
 go.mod                |  3 +++
 internal/mpeg/mpeg.go |  1 +
 main.go               | 43 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 go.mod
 create mode 100644 internal/mpeg/mpeg.go
 create mode 100644 main.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..438d886
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.netflux.io/rob/avframes
+
+go 1.15
diff --git a/internal/mpeg/mpeg.go b/internal/mpeg/mpeg.go
new file mode 100644
index 0000000..fb49537
--- /dev/null
+++ b/internal/mpeg/mpeg.go
@@ -0,0 +1 @@
+package mpeg
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..ed4d18d
--- /dev/null
+++ b/main.go
@@ -0,0 +1,43 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+const fname = "/home/rob/Desktop/example.mp3"
+
+const syncHeader1 = 0xFF
+const syncHeader2 = 0xFE
+
+func main() {
+	f, err := os.Open(fname)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	bufreader := bufio.NewReader(f)
+
+	buf := make([]byte, 4)
+	var i int
+	for {
+		_, err := io.ReadFull(bufreader, buf)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		if parseBytes(buf) {
+			fmt.Printf("Got possible header %X at %d\n", buf, i)
+		}
+
+		i++
+		bufreader.UnreadByte()
+	}
+}
+
+func parseBytes(buf []byte) bool {
+	return buf[0]&syncHeader1 == syncHeader1 || buf[0]&syncHeader2 == syncHeader2
+}