Audio buffer overflow

[jpcima]

Hi. When I instanciate either the DRO or S98 player, the Render method is going to overflow the output buffer and crash the program. It does not happen with VGM.

Diagnosing the problem, I discovered that it would be resolved, in a non-optimal way, when the smplStep is forced to 1. https://github.com/ValleyBell/libvgm/blob/07c6cc7d60b08db6995a3405dc0eb28800791f85/player/droplayer.cpp#L549 Indeed, a difference between VGM and DRO/S98 is that the former always uses the step value 1.

The issue does not happen in libvgm's own player. (possibly, due to allocating sufficient buffer so it doesn't happen) It has occurred in this context.

Also it probably doesn't matter but those were the files used: https://github.com/Wohlstand/OPL3BankEditor/tree/master/Bank_Examples/DOSBox

EDIT These have been values logged from DROPlayer before a situation of crash. curSmpl=0 smplCnt=7560 smplStep=7560

Valgrind trace

==18987== Invalid write of size 8
==18987==    at 0x483E817: memset (vg_replace_strmem.c:1251)
==18987==    by 0x68918A5: adlib_OPL2_getsample (adlibemu_opl_inc.c:1239)
==18987==    by 0x685C568: Resmpl_Exec_LinearDown (Resampler.c:343)
==18987==    by 0x685C568: Resmpl_Execute (Resampler.c:427)
==18987==    by 0x6850C2B: DROPlayer::Render(unsigned int, waveform_32bit_stereo*) (droplayer.cpp:549)
==18987==    by 0x684FA67: vgm_read(input_plugin_data*, char*, int) (vgm.cc:181)
==18987==    by 0x13513A: ip_read (input.c:695)
==18987==    by 0x13F4DF: _prebuffer (player.c:599)
==18987==    by 0x140D14: player_play_file (player.c:1205)
==18987==    by 0x11FEAC: browser_enter (browser.c:414)
==18987==    by 0x128145: run_command (command_mode.c:2882)
==18987==    by 0x11E7A0: u_getch (ui_curses.c:2163)
==18987==    by 0x11E7A0: main_loop (ui_curses.c:2272)
==18987==    by 0x11E7A0: main (ui_curses.c:2556)
==18987==  Address 0x53d2158 is 0 bytes after a block of size 39,768 alloc'd
==18987==    at 0x483777F: malloc (vg_replace_malloc.c:299)
==18987==    by 0x685C3E9: Resmpl_Init (Resampler.c:62)
==18987==    by 0x685151D: DROPlayer::Start() (droplayer.cpp:429)
==18987==    by 0x684FD46: vgm_open_after_map(input_plugin_data*) (vgm.cc:127)
==18987==    by 0x6850165: vgm_open(input_plugin_data*) (vgm.cc:55)
==18987==    by 0x134CF2: open_file_locked (input.c:463)
==18987==    by 0x134CF2: open_file (input.c:481)
==18987==    by 0x134CF2: ip_open (input.c:599)
==18987==    by 0x13F323: _producer_play (player.c:657)
==18987==    by 0x140CD4: player_play_file (player.c:1185)
==18987==    by 0x11FEAC: browser_enter (browser.c:414)
==18987==    by 0x128145: run_command (command_mode.c:2882)
==18987==    by 0x11E7A0: u_getch (ui_curses.c:2163)
==18987==    by 0x11E7A0: main_loop (ui_curses.c:2272)
==18987==    by 0x11E7A0: main (ui_curses.c:2556)