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Remove UBFix by using a union #739

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Remove UBFix by using a union #739

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52 changes: 16 additions & 36 deletions src/m4a.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1533,28 +1533,16 @@ void ply_xxx(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track)
gMPlayJumpTable[0](mplayInfo, track);
}

#define READ_XCMD_BYTE(var, n) \
{ \
u32 byte = track->cmdPtr[(n)]; \
byte <<= n * 8; \
(var) &= ~(0xFF << (n * 8)); \
(var) |= byte; \
}

void ply_xwave(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track)
{
u32 wav;

#ifdef UBFIX
wav = 0;
#endif
union { struct WaveData *w; u8 d[4]; } u;

READ_XCMD_BYTE(wav, 0) // UB: uninitialized variable
READ_XCMD_BYTE(wav, 1)
READ_XCMD_BYTE(wav, 2)
READ_XCMD_BYTE(wav, 3)
u.d[0] = *track->cmdPtr;
u.d[1] = *(track->cmdPtr + 1);
u.d[2] = *(track->cmdPtr + 2);
u.d[3] = *(track->cmdPtr + 3);

track->tone.wav = (struct WaveData *)wav;
track->tone.wav = u.w;
track->cmdPtr += 4;
}

Expand Down Expand Up @@ -1614,16 +1602,12 @@ void ply_xswee(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track

void ply_xwait(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track)
{
u32 len;
union { u16 a; u8 d[2]; } u;

#ifdef UBFIX
len = 0;
#endif

READ_XCMD_BYTE(len, 0) // UB: uninitialized variable
READ_XCMD_BYTE(len, 1)
u.d[0] = *track->cmdPtr;
u.d[1] = *(track->cmdPtr + 1);

if (track->timer < (u16)len)
if (track->timer < u.a)
{
track->timer++;
track->cmdPtr -= 2;
Expand All @@ -1638,18 +1622,14 @@ void ply_xwait(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track

void ply_xcmd_0D(struct MusicPlayerInfo *mplayInfo, struct MusicPlayerTrack *track)
{
u32 unk;

#ifdef UBFIX
unk = 0;
#endif
union { u32 a; u8 d[4]; } u;

READ_XCMD_BYTE(unk, 0) // UB: uninitialized variable
READ_XCMD_BYTE(unk, 1)
READ_XCMD_BYTE(unk, 2)
READ_XCMD_BYTE(unk, 3)
u.d[0] = *track->cmdPtr;
u.d[1] = *(track->cmdPtr + 1);
u.d[2] = *(track->cmdPtr + 2);
u.d[3] = *(track->cmdPtr + 3);

track->unk_3C = unk;
track->unk_3C = u.a;
track->cmdPtr += 4;
}

Expand Down