From 7e83be82cb6d64ba35c6d7cfa4907b9e3aa1261c Mon Sep 17 00:00:00 2001
From: "Alexander \"Arav\" Andreev" <me@arav.top>
Date: Wed, 21 Sep 2022 04:56:06 +0400
Subject: [PATCH] Calculate offset for ReadAt() instead of using Seek(). Fixed
 going out of bounds.

---
 internal/radio/icecast.go | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/internal/radio/icecast.go b/internal/radio/icecast.go
index a2b28cb..ba3d205 100644
--- a/internal/radio/icecast.go
+++ b/internal/radio/icecast.go
@@ -119,7 +119,8 @@ func IcecastLastSong(playlistPath string) (Song, error) {
 
 func icecastLastPlayedSongs(playlistPath string, n int) ([]Song, error) {
 	songs := make([]Song, n)
-	buf := make([]byte, bufferSize)
+	var buf []byte
+	var offset int64 = 0
 
 	playlist, err := os.Open(playlistPath)
 	if err != nil {
@@ -133,24 +134,29 @@ func icecastLastPlayedSongs(playlistPath string, n int) ([]Song, error) {
 		return nil, nil
 	}
 
-	playlist.Seek(-bufferSize, os.SEEK_END)
+	if playlist_stat.Size() < bufferSize {
+		buf = make([]byte, playlist_stat.Size())
+	} else {
+		buf = make([]byte, bufferSize)
+		offset = playlist_stat.Size() - bufferSize
+	}
 
-	_, err = playlist.Read(buf)
+	_, err = playlist.ReadAt(buf, offset)
 	if err != nil && err != io.EOF {
 		return nil, err
 	}
 
 	lines := bytes.Split(buf, []byte("\n"))
 
-	if len(lines) < 2 {
+	if len(lines) < 3 {
 		return nil, nil
 	}
 
-	if len(lines) < n {
-		n = len(lines)
-	}
+	lines = lines[:len(lines)-2]
 
-	lines = lines[len(lines)-n-2 : len(lines)-2]
+	if len(lines) > n {
+		lines = lines[len(lines)-n:]
+	}
 
 	for _, line := range lines {
 		fields := bytes.Split(line, []byte("|"))