i'm trying to read a CAF-file on OSX, using AudioToolbox's Extended Audio File API.
opening the file works fine, however, i need to access the UUID chunk, and i cannot find any reference on how to do that (or how to access any header-chunk of the file)
surely there must be a way to do this without parsing the file on my own.
PS: i can already do this with libsndfile, but i want to find a way to do this with only components that come with OSX.
i already tried calling ExtAudioFileGetProperty() with the ExtAudioFilePropertyID set to 'uuid' but this doesn't seem to work.
it turned out that the trick is not to use the ExtAudio API for accessing low-level functionality like the UUID chunk. (if you need to access the file via ExtAudio API, it's possible to create an ExtAudioHandle from an AudioFileID.)
in the end i used something like this:
AudioFileID fileID;
ExtAudioFileRef extFile;
OSStatus err = AudioFileOpenURL((CFURLRef)inURL, kAudioFileReadPermission, 0, &fileID);
if(noErr!=err)return;
err = ExtAudioFileWrapAudioFileID (fileID, false, &extFile); // in case we *also* want to access the file via ExtAudio
if(noErr!=err)return;
for(index=0; ; index++) {
UInt32 size=0;
char*data=NULL;
OSStatus err = AudioFileGetUserDataSize (fileID,'uuid',index,&size);
if(noErr!=err)break; // check whether we were able to read the chunksize
if(0==size)continue; // check whether there is some payload in the uuid chunk
data=calloc(size, 1);
if(!data)continue;
err = AudioFileGetUserData (fileID, 'uuid', index, &size, data);
if(noErr!=err){free(data); break;} // check whether we were able to read the chunksize
/* ... */
free(data);
}
ExtAudioFileDispose(extFile);
AudioFileClose(fileID);
Related
I am trying to create a program that any normal user can run on windows and generate a process list of all processes, including the executable location. I have used CreateToolhelp32Snapshot() to get all process names, pid, ppid. But having issues getting the image path. Everything I do results in pretty much Access Denied.
I have tried ZwQueryInformationProcess, GetProcessImageFileName, etc. and also using OpenProcess to get the handle to each process. I can get the handle by using PROCESS_QUERY_LIMITED_INFORMATION, but any other option doesn't work. I am lost and have been at this for a few days. Can anyone point me in the right direction?
This is the code that works for non-admin user on Windows. Use the szExeFile member of PROCESSENTRY32 to get the path:
HANDLE hProcessSnap = NULL;
HANDLE hProcess = NULL;
PROCESSENTRY32 pe32;
DWORD dwPriorityClass = 0;
// Take a snapshot of all processes in the system.
hProcessSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (hProcessSnap == INVALID_HANDLE_VALUE)
{
return;
}
// Set the size of the structure before using it.
pe32.dwSize = sizeof(PROCESSENTRY32);
// Retrieve information about the first process,
// and exit if unsuccessful
if (!Process32First(hProcessSnap, &pe32))
{
CloseHandle(hProcessSnap); // clean the snapshot object
return;
}
// Now walk the snapshot of processes, and
// display information about each process in turn
do
{
// do something with the pe32 struct.
// pe32.szExeFile -> path of the file
} while (Process32Next(hProcessSnap, &pe32));
CloseHandle(hProcessSnap);
Under Linux, my program would do something like this:
Process 1 opens a file (e.g. by mapping it into memory). Let's call this file#1
Process 2 unlinks the file, and creates a new file with the same name. Let's call this file#2.
Process 1 continues to work with file#1. When it is closed, it is deleted (since it has no links). Process 1 continues to work with the content in file#1, and does not see content from file#2.
When both processes have exited, file#2 remains on disk.
I want to achieve the same semantics in Windows. After reading this question, I think FILE_SHARE_DELETE does basically this. Is opening the file with FILE_SHARE_DELETE enough, or do I need to consider something more?
The above execution flow is just an example, I know there are other ways of solving that exact problem in Windows, but I want to understand how to make such code portable between Windows and Linux.
Edit: to clarify: The use cases would be to reuse a filename for different unrelated files, but let existing processes keep their data (think transactional update of a config file for example), and to make a file anonymous (unnamed), but continue to use it like an anonymous memory map. Again I know both are possible on Windows through other means, but I am trying to find a way that is portable across platforms.
You can achieve this by using a combination of CreateFile, CreateFileMapping and MapViewOfFile calls. MapViewOfFile will give you a memory-mapped buffer of the file backed by the file on disk.
Following code when executed from different processes, will write the process id of last closing process in the file at c:\temp\temp.txt
int main()
{
TCHAR szMsg[256];
HANDLE hMapFile;
LPCTSTR pBuf;
HANDLE hFile = CreateFileW(
L"C:\\Temp\\temp.txt",
GENERIC_WRITE|GENERIC_READ,
FILE_SHARE_DELETE|FILE_SHARE_READ|FILE_SHARE_WRITE,
NULL,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL,NULL);
hMapFile = CreateFileMapping(
hFile, // Handle of file opened with rw access
NULL, // default security
PAGE_READWRITE, // read/write access
0, // maximum object size (high-order DWORD)
BUF_SIZE, // maximum object size (low-order DWORD)
szName); // name of mapping object
if (hMapFile == NULL)
{
printf( "Could not create file mapping object (%d).\n", GetLastError());
return 1;
}
pBuf = (LPTSTR) MapViewOfFile(hMapFile, // handle to map object
FILE_MAP_ALL_ACCESS, // read/write permission
0,
0,
BUF_SIZE);
if (pBuf == NULL)
{
printf("Could not map view of file (%d).\n", GetLastError());
CloseHandle(hMapFile);
return 1;
}
wsprintfW(szMsg, L"This is process id %d", GetCurrentProcessId());
CopyMemory((PVOID)pBuf, szMsg, (wcslen(szMsg) * sizeof(TCHAR)));
MessageBoxW(NULL, szMsg, L"Check", MB_OK);
UnmapViewOfFile(pBuf);
CloseHandle(hMapFile);
CloseHandle(hFile);
return 0;
}
Make sure you open the file with GENERIC_READ|GENERIC_WRITE access and allow FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE access to subsequent opens.
Also note the use of CREATE_ALWAYS in CreateFile which will delete the old file and open a new one every-time CreateFile is called. This is the 'unlink' effect you talk about.
Code inspired from Creating Named Shared Memory at msdn.
I need to play raw PCM data (16 bit signed) using CoreAudio on OS X. I get it from network using UDP socket (on sender side data is captured from microphone).
The problem is that all I hear now is some short cracking noise and then only silence.
I'm trying to play data using AudioQueue. I setup it like this:
// Set up stream format fields
AudioStreamBasicDescription streamFormat;
streamFormat.mSampleRate = 44100;
streamFormat.mFormatID = kAudioFormatLinearPCM;
streamFormat.mFormatFlags = kLinearPCMFormatFlagIsBigEndian | kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked;
streamFormat.mBitsPerChannel = 16;
streamFormat.mChannelsPerFrame = 1;
streamFormat.mBytesPerPacket = 2 * streamFormat.mChannelsPerFrame;
streamFormat.mBytesPerFrame = 2 * streamFormat.mChannelsPerFrame;
streamFormat.mFramesPerPacket = 1;
streamFormat.mReserved = 0;
OSStatus err = noErr;
// create the audio queue
err = AudioQueueNewOutput(&streamFormat, MyAudioQueueOutputCallback, myData, NULL, NULL, 0, &myData->audioQueue);
if (err)
{ PRINTERROR("AudioQueueNewOutput"); myData->failed = true; result = false;}
// allocate audio queue buffers
for (unsigned int i = 0; i < kNumAQBufs; ++i) {
err = AudioQueueAllocateBuffer(myData->audioQueue, kAQBufSize, &myData->audioQueueBuffer[i]);
if (err)
{ PRINTERROR("AudioQueueAllocateBuffer"); myData->failed = true; break; result = false;}
}
// listen for kAudioQueueProperty_IsRunning
err = AudioQueueAddPropertyListener(myData->audioQueue, kAudioQueueProperty_IsRunning, MyAudioQueueIsRunningCallback, myData);
if (err)
{ PRINTERROR("AudioQueueAddPropertyListener"); myData->failed = true; result = false;}
MyAudioQueueOutputCallback is:
void MyAudioQueueOutputCallback(void* inClientData,
AudioQueueRef inAQ,
AudioQueueBufferRef inBuffer)
{
// this is called by the audio queue when it has finished decoding our data.
// The buffer is now free to be reused.
MyData* myData = (MyData*)inClientData;
unsigned int bufIndex = MyFindQueueBuffer(myData, inBuffer);
// signal waiting thread that the buffer is free.
pthread_mutex_lock(&myData->mutex);
myData->inuse[bufIndex] = false;
pthread_cond_signal(&myData->cond);
pthread_mutex_unlock(&myData->mutex);
}
MyAudioQueueIsRunningCallback is:
void MyAudioQueueIsRunningCallback(void* inClientData,
AudioQueueRef inAQ,
AudioQueuePropertyID inID)
{
MyData* myData = (MyData*)inClientData;
UInt32 running;
UInt32 size;
OSStatus err = AudioQueueGetProperty(inAQ, kAudioQueueProperty_IsRunning, &running, &size);
if (err) { PRINTERROR("get kAudioQueueProperty_IsRunning"); return; }
if (!running) {
pthread_mutex_lock(&myData->mutex);
pthread_cond_signal(&myData->done);
pthread_mutex_unlock(&myData->mutex);
}
}
and MyData is:
struct MyData
{
AudioQueueRef audioQueue; // the audio queue
AudioQueueBufferRef audioQueueBuffer[kNumAQBufs]; // audio queue buffers
AudioStreamPacketDescription packetDescs[kAQMaxPacketDescs]; // packet descriptions for enqueuing audio
unsigned int fillBufferIndex; // the index of the audioQueueBuffer that is being filled
size_t bytesFilled; // how many bytes have been filled
size_t packetsFilled; // how many packets have been filled
bool inuse[kNumAQBufs]; // flags to indicate that a buffer is still in use
bool started; // flag to indicate that the queue has been started
bool failed; // flag to indicate an error occurred
bool finished; // flag to inidicate that termination is requested
pthread_mutex_t mutex; // a mutex to protect the inuse flags
pthread_mutex_t mutex2; // a mutex to protect the AudioQueue buffer
pthread_cond_t cond; // a condition varable for handling the inuse flags
pthread_cond_t done; // a condition varable for handling the inuse flags
};
I'm sorry if I posted too much code - hope it helps anyone to understand what exactly I do.
Mostly my code based on this code which is version of AudioFileStreamExample from Mac Developer Library adapted to work with CBR data.
Also I looked at this post and tried AudioStreamBasicDescription desribed there. And tried to change my flags to Little or Big Endian. It didn't work.
I looked at some another posts here and in the other resources while finding similar problem, I checked the order of my PCM data, for example. I just can't post more than two links.
Please anyone help me to understand what I'm doing wrong! Maybe I should abandon this way and use Audio Units right away? I'm just very newbie in CoreAudio and hoped that mid-level of CoreAudio will help me to solve this problem.
P.S. Sorry for my English, I tried as I can.
I hope you've solved this one on your own already, but for the benefit of other people who are having this problem, I'll post up an answer.
The problem is most likely because once an Audio Queue is started, time continues moving forward, even if you stop enqueueing buffers. But when you enqueue a buffer, it is enqueued with a timestamp that is right after the previously enqueued buffer. This means that if you don't stay ahead of the where the audio queue is playing, you will end up enqueuing buffers with a timestamp in the past, therefore the audio queue will go silent and the isRunning property will still be true.
To work around this, you have a couple of options. The simplest in theory would be to never fall behind on submitting buffers. But since you are using UDP, there is no guarantee that you will always have data to submit.
Another option is that you can keep track of what sample you should be playing and submit an empty buffer of silence whenever you need to have a gap. This option works good if your source data has timestamps that you can can use to calculate how much silence you need. But ideally, you wouldn't need to do this.
Instead you should be calculating the timestamp for the buffer using the system time. Instead of AudioQueueEnqueueBuffer, you'll need to use AudioQueueEnqueueBufferWithParameters instead. You just need to make sure the timestamp is ahead of where the queue is currently at. You'll also have to keep track what the system time was when you started the queue, so you can calculate the correct timestamp for each buffer you are submitting. If you have timestamp values on your source data, you should be able to use them to calculate the buffer timestamps as well.
I am trying to delete all the temporary files created by my application during uninstall. I use the following code:
bool DeleteFileNow( QString filenameStr )
{
wchar_t* filename;
filenameStr.toWCharArray(filename);
QFileInfo info(filenameStr);
// don't do anything if the file doesn't exist!
if (!info.exists())
return false;
// determine the path in which to store the temp filename
wchar_t* path;
info.absolutePath().toWCharArray(path);
TRACE( "Generating temporary name" );
// generate a guaranteed to be unique temporary filename to house the pending delete
wchar_t tempname[MAX_PATH];
if (!GetTempFileNameW(path, L".xX", 0, tempname))
return false;
TRACE( "Moving real file name to dummy" );
// move the real file to the dummy filename
if (!MoveFileExW(filename, tempname, MOVEFILE_REPLACE_EXISTING))
{
// clean up the temp file
DeleteFileW(tempname);
return false;
}
TRACE( "Queueing the OS" );
// queue the deletion (the OS will delete it when all handles (ours or other processes) close)
return DeleteFileW(tempname) != FALSE;
}
My application is crashing. I think its due to some missing windows dll for the operations performed. Is there any other way to perform the same operation using Qt alone?
Roku have already told your problem in manipulating with QString and wchar_t*.
See the documentation: QString Class Reference, method toWCharArray:
int QString::toWCharArray ( wchar_t * array ) const
Fills the array with the data contained in this QString object. The array is encoded in utf16 on platforms where wchar_t is 2 bytes wide (e.g. windows) and in ucs4 on platforms where wchar_t is 4 bytes wide (most Unix systems).
array has to be allocated by the caller and contain enough space to hold the complete string (allocating the array with the same length as the string is always sufficient).
returns the actual length of the string in array.
If you are simply looking for a way to remove a file using Qt, use QFile::remove:
QFile file(fileNameStr);
file.remove(); // Returns a bool; true if successful
If you want Qt to manage the entire life cycle of a temporary file for you, take a look at QTemporaryFile:
QTemporaryFile tempFile(fileName);
if (tempFile.open())
{
// Do stuff with file here
}
// When tempFile falls out of scope, it is automatically deleted.
Loading bundle from memory is possible by NSCreateObjectFileImageFromMemory function. Does anyone have successful experience in this area? Does anyone have working sample for this function?
My code is as:
text srcPath = "/Applications/TextEdit.app/Contents/MacOS/TextEdit";
data_t data;
data.loadFromFile(srcPath);
void *addr;
kern_return_t err;
NSObjectFileImage img = nil;
NSObjectFileImageReturnCode dyld_err;
err = vm_allocate(mach_task_self(), (vm_address_t *)&addr,
data.length(), true);
if(err == 0)
{
//err = vm_write(mach_task_self(), (vm_address_t)addr,
//(vm_address_t)(char*)data, data.length());
memcpy(addr, (char*)data, data.length());
if(err == 0)
dyld_err =
NSCreateObjectFileImageFromMemory(addr, data.length(), &img);
// error is NSObjectFileImageFailure
}
The img variable is null (error is NSObjectFileImageFailure). Why?
Thankyou.
From the manpage, it looks like only MH_BUNDLE files can be loaded with NSCreateObjectFileImageFromMemory() and friends.
MH_BUNDLE files are explained here.
The MH_BUNDLE file type is the type typically used by code that you
load at runtime (typically called bundles or plug-ins). By convention,
the file name extension for this format is .bundle.
Note that that manpage is for 10.4 and there does not appear to be a newer version available.