From e4db28039c20bd83f0706779e1b6199c40ad625b Mon Sep 17 00:00:00 2001
From: Roman Fomin <rfomin@gmail.com>
Date: Thu, 18 Aug 2022 17:29:41 +0700
Subject: [PATCH] Revert "implement check for MP3's (#700)"

This reverts commit 80b959915b200b36cef58162ccc68d6605ae92d4.
---
 src/i_sdlmusic.c | 98 ++++++------------------------------------------
 1 file changed, 11 insertions(+), 87 deletions(-)

diff --git a/src/i_sdlmusic.c b/src/i_sdlmusic.c
index 6d457c91..13050adf 100644
--- a/src/i_sdlmusic.c
+++ b/src/i_sdlmusic.c
@@ -179,85 +179,6 @@ static void I_SDL_UnRegisterSong(void *handle)
    }
 }
 
-// MP3 check adapted from https://github.com/lieff/minimp3
-
-static size_t mp3dec_skip_id3v2(const byte *buf, size_t buf_size)
-{
-    if (buf_size >= 10 && !memcmp(buf, "ID3", 3) && !((buf[5] & 15) ||
-        (buf[6] & 0x80) || (buf[7] & 0x80) || (buf[8] & 0x80) || (buf[9] & 0x80)))
-    {
-        size_t id3v2size = (((buf[6] & 0x7f) << 21) | ((buf[7] & 0x7f) << 14) |
-                            ((buf[8] & 0x7f) << 7)  |  (buf[9] & 0x7f)) + 10;
-        if ((buf[5] & 16))
-            id3v2size += 10; // footer
-        return id3v2size;
-    }
-    return 0;
-}
-
-#define HDR_GET_LAYER(h)            (((h[1]) >> 1) & 3)
-#define HDR_GET_BITRATE(h)          ((h[2]) >> 4)
-#define HDR_GET_SAMPLE_RATE(h)      (((h[2]) >> 2) & 3)
-#define HDR_IS_FREE_FORMAT(h)       (((h[2]) & 0xF0) == 0)
-
-static int hdr_valid(const byte *h)
-{
-    return h[0] == 0xFF &&
-        ((h[1] & 0xF0) == 0xF0 || (h[1] & 0xFE) == 0xE2) &&
-        (HDR_GET_LAYER(h) != 0) &&
-        (HDR_GET_BITRATE(h) != 15) &&
-        (HDR_GET_SAMPLE_RATE(h) != 3);
-}
-
-static int hdr_compare(const byte *h1, const byte *h2)
-{
-    return ((h1[1] ^ h2[1]) & 0xFE) == 0 &&
-           ((h1[2] ^ h2[2]) & 0x0C) == 0 &&
-           !(HDR_IS_FREE_FORMAT(h1) ^ HDR_IS_FREE_FORMAT(h2));
-}
-
-static boolean IsValidMP3(const byte *buf, size_t buf_size)
-{
-#define HDR_SIZE         4
-#define MAX_HDR_COMPARES 10
-// buffer which can hold minimum 64 consecutive mp3 frames worst case
-#define MAX_CHECK_SIZE (64*1024)
-
-    int i;
-    byte *hdr = NULL;
-    int compare = 0;
-
-    i = mp3dec_skip_id3v2(buf, buf_size);
-
-    while (i < buf_size - HDR_SIZE && i < MAX_CHECK_SIZE)
-    {
-        if (hdr_valid(buf + i))
-        {
-            if (!hdr)
-            {
-                hdr = (byte *)buf + i;
-                i += HDR_SIZE;
-                continue;
-            }
-            else
-            {
-                if (hdr_compare(hdr, buf + i))
-                    return true;
-                if (compare < MAX_HDR_COMPARES)
-                {
-                    ++compare;
-                    i += HDR_SIZE;
-                    continue;
-                }
-                return false;
-            }
-        }
-        ++i;
-    }
-
-    return false;
-}
-
 //
 // I_RegisterSong
 //
@@ -268,15 +189,18 @@ static void *I_SDL_RegisterSong(void *data, int size)
 
    if (!IsMus(data, size))
    {
-      rw = SDL_RWFromMem(data, size);
+      // Workaround for SDL_mixer doesn't always detect mp3s
+      // https://github.com/libsdl-org/SDL_mixer/issues/288
+      const SDL_version *ver = Mix_Linked_Version();
+      if (ver->major == 2 && ver->minor == 0 && (ver->patch == 2 || ver->patch == 4))
+      {
+        byte *magic = data;
+        if (size >= 2 && magic[0] == 0xFF && magic[1] == 0xF3)
+          magic[1] = 0xFA;
+      }
+      rw    = SDL_RWFromMem(data, size);
+      music = Mix_LoadMUS_RW(rw, false);
 
-      if (IsValidMP3(data, size))
-         music = Mix_LoadMUSType_RW(rw, MUS_MP3, false);
-      else
-         music = Mix_LoadMUS_RW(rw, false);
-
-      if (!music)
-         printf("I_SDL_RegisterSong: %s\n", SDL_GetError());
    }
    else // Assume a MUS file and try to convert
    {