Im using the Qt regex utilities to match and capture data from an input
string. I get a new String every couple of milliseconds and have to run
the same regex over it each time. It works great for awhile, but will
randomly crash at points and I can't figure out why. There are no
exceptions, it just kills the jvm. The reason I switched to the Qt
regex engine from the java regex engine is the java regex engine was
causing a memory leak and had allocated over 20mb worth of boolean[]
arrays. It seems to be happening with the exactMatch and cap(int)
methods and I can not figure out how to reproduce it or what causes as
it happens like once out of a few thousand input strings. My crash logs
always show one of two things on the stack, either:
Stack: [0x06020000,0x06070000], sp=0x0606f8a0, free space=318k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code,
C=native code)
C [ntdll.dll+0x659c3]
C [ntdll.dll+0x65883]
C [kernel32.dll+0x4c56f]
C [msvcrt.dll+0x9d6b]
C [QtCore4.dll+0x167b43]
C [QtCore4.dll+0x167cb0]
C [QtCore4.dll+0x4e0ef]
C [QtCore4.dll+0x4e298]
C [com_trolltech_qt_core.dll+0x7a9df]
J
com.trolltech.qt.core.QRegExp.__qt_exactMatch_String(JLjava/lang/String;)Z
J com.trolltech.qt.core.QRegExp.exactMatch(Ljava/lang/String;)Z
or:
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code,
C=native code)
V [jvm.dll+0xcf007]
C [com_trolltech_qt_core.dll+0x7a75f]
J com.trolltech.qt.core.QRegExp.__qt_cap_int(JI)Ljava/lang/String;
J com.trolltech.qt.core.QRegExp.cap(I)Ljava/lang/String;
// source (i know these regex patterns arn't the most efficient, but
faster than using String methods)
private final String AREGEX =
"[A:\\s]*([\\d.]*)[\\s]*\\([\\d.:]*\\)[\\s](?:of[\\s]*[\\d.]*[\\s]*\\([\\d\\s.:]*\\)|)[\\s]*([\\d.?,]*)%(?:[\\s]*([\\d.]*)%|)(?:[\\s]*([\\d.]*)x.*|.*)";
private final String REGEX =
"[A:\\s]*([\\d.]*)[V:\\s]*([\\d.]*)[A\\-V:\\s]*([\\d.\\-]*)[ct:\\s]*([\\d.\\-]*)[\\s]*([\\d]*)[\\s]*/[\\s]*([\\d]*)\\s*([\\d.?]*)[%\\s]*([\\d.?]*)[%\\s]*([\\d.?]*)[%\\s]*([\\d]*)\\s([\\d]*)[\\s]*([\\d]*)[%\\s]*(?:([\\d.]*)x.*|.*)";
//...
private QRegExp aregex = new QRegExp(AREGEX);
private QRegExp regex = new QRegExp(REGEX);
//...
if (aregex.exactMatch(line)) {
try {
cfile.audio_position = Double.parseDouble(aregex.cap(1));
cfile.ac_cpu_time = Double.parseDouble(aregex.cap(2));
String mat = aregex.cap(3);
if (mat != null && !mat.equals("")) {
cfile.cache_use = Integer.parseInt(mat);
}
mat = aregex.cap(4);
if (mat != null && !mat.equals("")) {
cfile.playback_speed = Double.parseDouble(mat);
}
} catch (NumberFormatException ex) { }
}
else if (regex.exactMatch(line)) {
try {
cfile.video_position = Double.parseDouble(regex.cap(2));
cfile.audio_position =
Double.parseDouble(regex.cap(1).trim());
cfile.avsync = Double.parseDouble(regex.cap(3));
cfile.avcorrection = Double.parseDouble(regex.cap(4));
cfile.frames_rendered = Integer.parseInt(regex.cap(5));
cfile.frames_decoded = Integer.parseInt(regex.cap(6));
cfile.frames_buffered = cfile.frames_decoded -
cfile.frames_rendered;
cfile.vc_cpu_time = Double.parseDouble(regex.cap(7));
cfile.vo_cpu_time = Double.parseDouble(regex.cap(8));
cfile.ac_cpu_time = Double.parseDouble(regex.cap(9));
cfile.correction_frame_drop =
Integer.parseInt(regex.cap(10));
} catch (NumberFormatException ex) { }
}
Thanks,
- Dave
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