From 37bc9d5ec65cc584ab24508011b0d86423418ab8 Mon Sep 17 00:00:00 2001
From: Markus Birth <markus@birth-online.de>
Date: Mon, 27 May 2024 20:04:23 +0100
Subject: [PATCH] Optimise id3v2 header parsing
---
src/Mp3Info.php | 78 ++++++++++++++++++++++++++++---------------------
1 file changed, 44 insertions(+), 34 deletions(-)
diff --git a/src/Mp3Info.php b/src/Mp3Info.php
index e8c0ca9..ea90e22 100644
--- a/src/Mp3Info.php
+++ b/src/Mp3Info.php
@@ -166,11 +166,13 @@ class Mp3Info
* @var int Major version of id3v2 tag (if id3v2 present) (2 or 3 or 4)
*/
public $id3v2MajorVersion;
+ public $id3v2Version;
/**
* @var int Minor version of id3v2 tag (if id3v2 present)
*/
public $id3v2MinorVersion;
+ public $id3v2Revision;
/**
* @var array List of id3v2 header flags (if id3v2 present)
@@ -501,45 +503,53 @@ class Mp3Info
private function readId3v2Body()
{
// read the rest of the id3v2 header
- $raw = $this->fileObj->getBytes(7);
- $data = unpack('Cmajor_version/Cminor_version/Cflags/C4size', $raw);
- $this->id3v2MajorVersion = $data['major_version'];
- $this->id3v2MinorVersion = $data['minor_version'];
- $flags = decbin($data['flags']);
- if ($this->id3v2MajorVersion == 2) { // parse id3v2.2.0 header flags
- $this->id3v2Flags = array(
- 'unsynchronisation' => (bool)substr($flags, 0, 1),
- 'compression' => (bool)substr($flags, 1, 1),
- );
- } else if ($this->id3v2MajorVersion == 3) { // parse id3v2.3.0 header flags
- $this->id3v2Flags = array(
- 'unsynchronisation' => (bool)substr($flags, 0, 1),
- 'extended_header' => (bool)substr($flags, 1, 1),
- 'experimental_indicator' => (bool)substr($flags, 2, 1),
- );
- if ($this->id3v2Flags['extended_header'])
- throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
- } else if ($this->id3v2MajorVersion == 4) { // parse id3v2.4.0 header flags
- $this->id3v2Flags = array(
- 'unsynchronisation' => (bool)substr($flags, 0, 1),
- 'extended_header' => (bool)substr($flags, 1, 1),
- 'experimental_indicator' => (bool)substr($flags, 2, 1),
- 'footer_present' => (bool)substr($flags, 3, 1),
- );
- if ($this->id3v2Flags['extended_header'])
- throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
- if ($this->id3v2Flags['footer_present'])
- throw new \Exception('NEED TO PARSE id3v2.4 FOOTER!');
- }
- $size = $data['size1'] << 21 | $data['size2'] << 14 | $data['size3'] << 7 | $data['size4'];
+ $raw = $this->fileObj->getBytes(3);
+ $data = unpack('Cversion/Crevision/Cflags', $raw);
+ $this->id3v2Version = $data['version'];
+ $this->id3v2Revision = $data['revision'];
+ // backwards compatibility:
+ $this->id3v2MajorVersion = $data['version'];
+ $this->id3v2MinorVersion = $data['revision'];
- if ($this->id3v2MajorVersion == 2) {
+ $flags = str_pad(decbin($data['flags']), 8, '0', STR_PAD_LEFT);
+ $this->id3v2Flags = array();
+
+ if ($this->id3v2Version >= 2) {
+ // parse id3v2.2.0 header flags
+ $this->id3v2Flags['unsynchronisation'] = (bool)substr($flags, 0, 1);
+ $this->id3v2Flags['compression'] = (bool)substr($flags, 1, 1);
+ }
+
+ if ($this->id3v2Version >= 3) {
+ // id3v2.3 changes second bit from compression to extended_header
+ $this->id3v2Flags['extended_header'] = &$this->id3v2Flags['compression'];
+ unset($this->id3v2Flags['compression']);
+ // parse additional id3v2.3.0 header flags
+ $this->id3v2Flags['experimental_indicator'] = (bool)substr($flags, 2, 1);
+
+ if ($this->id3v2Flags['extended_header']) {
+ throw new Exception('NEED TO PARSE EXTENDED HEADER!');
+ }
+ }
+
+ if ($this->id3v2Version >= 4) {
+ // parse additional id3v2.4.0 header flags
+ $this->id3v2Flags['footer_present'] = (bool)substr($flags, 3, 1);
+
+ if ($this->id3v2Flags['footer_present']) {
+ throw new Exception('NEED TO PARSE id3v2.4 FOOTER!');
+ }
+ }
+
+ $size = $this->getSyncsafeSize($this->fileObj->getBytes(4));
+
+ if ($this->id3v2Version == 2) {
// parse id3v2.2.0 body
/*throw new \Exception('NEED TO PARSE id3v2.2.0 flags!');*/
- } elseif ($this->id3v2MajorVersion == 3) {
+ } elseif ($this->id3v2Version == 3) {
// parse id3v2.3.0 body
$this->parseId3v23Body(10 + $size);
- } elseif ($this->id3v2MajorVersion == 4) {
+ } elseif ($this->id3v2Version == 4) {
// parse id3v2.4.0 body
$this->parseId3v24Body(10 + $size);
}