Fixed bug #46
authorSam Lantinga <slouken@libsdl.org>
Tue, 14 Mar 2006 05:34:39 +0000
changeset 1524 38a12fd1a2c1
parent 1523 21b1fbb53f4a
child 1525 23a347cfbed8
Fixed bug #46 Date: Fri, 13 Jan 2006 18:09:45 -0500 From: mhall4400 vipmail kvcc edu Subject: Possible SDL bug Greetings I believe Ive come across a bug in your SDL product (1.2.9), in the CD-ROM control portion of the library. When calling the SDL_CDPlay() function to play the last track of a CD using the offset and length from an SDL_CD structure generated by SDL_CDOpen(), I get the following error from a call to SDL_Error(): mciSendCommand() error: The specified parameter is out of range for the specified command. The code returning the error is: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, g_playingDriveSDLCD->track[trackNumberInt].length) Subtracting one from the length of the provided length seems to repair the problem: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, (g_playingDriveSDLCD->track[trackNumberInt].length) - 1) Ive replicated this problem on Windows 98 SE (several months since last patch), fully-patched Window ME, seldom-patched Windows XP SP1, and fully-patched Windows XP SP2. While investigating the issue, I came across a line in your librarys win32 source code in file \src\cdrom\win32\SDL_syscdrom.c (source code zip archive from your download page), function: SDL_SYS_CDGetTOC(), line 226 where you add 1 to the value for length to fix MCI last track length bug. This may be the source of the issue (because subtracting 1 from the length seems to resolve the issue). Microsoft may have patched the referenced bug since you wrote that line. Mike Hall
src/cdrom/win32/SDL_syscdrom.c
--- a/src/cdrom/win32/SDL_syscdrom.c	Tue Mar 14 04:00:03 2006 +0000
+++ b/src/cdrom/win32/SDL_syscdrom.c	Tue Mar 14 05:34:39 2006 +0000
@@ -216,8 +216,7 @@
 				cdrom->track[i - 1].length = MSF_TO_FRAMES(
 					MCI_MSF_MINUTE(mci_status.dwReturn),
 					MCI_MSF_SECOND(mci_status.dwReturn),
-					MCI_MSF_FRAME(mci_status.dwReturn)) + 1; /* +1 to fix */
-											/* MCI last track length bug */
+					MCI_MSF_FRAME(mci_status.dwReturn));
 				/* compute lead-out offset */
 				cdrom->track[i].offset = cdrom->track[i - 1].offset +
 					cdrom->track[i - 1].length;