hello every one i want to ask you if you know a way to extract data from message_t
in the oldest version of TinyOs there are TOS_Msg and TOS_MsgPtr but in message_t i could't find a way please help me
and i want to know if there is any data type to store data like table or array list
typedef nx_struct message_localization{
nx_uint8_t NodeId;
bool ancre_nature;
nx_uint8_t x_coordinate;
nx_uint8_t y_coordinate;
x_uint8_t energie_transmited;
} message_localization_t;
The Packet interface has a command getPayload which does want you want:
command void *getPayload(message_t *msg, uint8_t len);
See the documentation for more information.
To access the data field, you may do as follows:
message_t msg;
message_localization_t *payload =
(message_localization_t *)call Packet.getPayload(
&msg, sizeof(message_localization_t));
payload->x_coordinate = x;
payload->y_coordinate = y;
/* and so on */
The same command is for convenience included in interfaces Send and AMSend. Packet and AMSend are provided by the ActiveMessageC configuration.
Related
I'm trying to understand how devicetrees work.
According to the kernel documentation, they are used, in arm architecture, in the following manner:
In the majority of cases, the machine identity is irrelevant, and the kernel will instead select setup code based on the machine’s core CPU or SoC. On ARM for example, setup_arch() in arch/arm/kernel/setup.c will call setup_machine_fdt() in arch/arm/kernel/devtree.c which searches through the machine_desc table and selects the machine_desc which best matches the device tree data. It determines the best match by looking at the ‘compatible’ property in the root device tree node, and comparing it with the dt_compat list in struct machine_desc (which is defined in arch/arm/include/asm/mach/arch.h if you’re curious).
The ‘compatible’ property contains a sorted list of strings starting with the exact name of the machine, followed by an optional list of boards it is compatible with sorted from most compatible to least.
I found the source code related to the comparison of machine_desc to the compatible parameter set in the dts file:
const struct machine_desc * __init setup_machine_fdt(void *dt_virt)
{
const struct machine_desc *mdesc, *mdesc_best = NULL;
#if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M)
DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
.l2c_aux_val = 0x0,
.l2c_aux_mask = ~0x0,
MACHINE_END
mdesc_best = &__mach_desc_GENERIC_DT;
#endif
if (!dt_virt || !early_init_dt_verify(dt_virt))
return NULL;
mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
if (!mdesc) {
const char *prop;
int size;
unsigned long dt_root;
early_print("\nError: unrecognized/unsupported "
"device tree compatible list:\n[ ");
dt_root = of_get_flat_dt_root();
prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
while (size > 0) {
early_print("'%s' ", prop);
size -= strlen(prop) + 1;
prop += strlen(prop) + 1;
}
early_print("]\n\n");
dump_machine_table(); /* does not return */
}
/* We really don't want to do this, but sometimes firmware provides buggy data */
if (mdesc->dt_fixup)
mdesc->dt_fixup();
early_init_dt_scan_nodes();
/* Change machine number to match the mdesc we're using */
__machine_arch_type = mdesc->nr;
return mdesc;
}
However, I didn't find machine_desc table definition.
If I'd like to read all machine_desc, Where can I find it?
TL;DR - The machine description is built by building and linking different source files into the kernel. So each machine source file adds an entry into the table.
The table is based in arch/arm/kernel/vmlinux.lds.S (or relevant architecture linker file). It is built with the macros MACHINE_START and MACHINE_END. This places a structure in the 'arch.info.init' sections of the object file. All of these objects get globbed together by the linker. This forms the table. So, it is constructed by linking different source files with the MACHINE_START and MACHINE_END macros. Therefore, it doesn't exist in one place.
However, you can use git grep -A10 MACHINE_START to get a fairly good list. This command works well, as typically, it is the last thing in the file so only five or six lines may print. Or you could write init code to dump the table by printing the machine_desc entries.
That said, the table is not too interesting as it is just function pointers to call at different times. The majority will be NULL as it used designated initializers.
Related: Control to 'dt_machine_start' on Android
I read bytes from a microcontroller in VC++2010(that i dont know absolutely but i must use as in lack of someone else) using SerialPort and on DataReceived event.
private: System::Void serialPort1_DataReceived(System::Object^ sender,
System::IO::Ports::SerialDataReceivedEventArgs^ e)
{
String^mystr;
mystr = serialPort1->ReadExisting();
I need raw data but everything >0x7F looks changed to 0x3F.
in the watch window mystr[3]=0x3F,despite i sent 0x80;
Why are some data lost?I expect that a raw byte could be converted in a char ,maybe an impossible to print char,but without altering the data.
Is there any way to have an array of raw data instead?
Thanks
I can write a video file using images which I learned with this sample here. It uses IMFSample and IMFSinkWriter. Now I want to add audio to it. Suppose there is Audio.wma file and I want this audio to be written in that video file.
But cannot figure out how to do that in this sample. Things like input & output type setup, IMFSample creation for audio buffer etc. It would be a great if someone could show me how to add audio to a video file using sink writer.
Media Foundation is great to work with, and I am certain you will be able to quickly modify your project to get this done.
OVERVIEW:
Create new IMFMediaSource to read the samples from the audio file, add an audio stream to the sink, and finally interleave the sink writes using the corresponding stream index.
DETAILS:
Modify the VideoGenerator::InitializeSinkWriter(..) function to properly initialize the sink to accommodate the audio stream. In that function, properly create the audioTypeOut and audioTypeIn (IMFMediaType). You may want to rename mediaTypeOut and mediaTypeIn to videoTypeOut and videoTypeIn for clarity, which would appear like the following:
ComPtr<IMFMediaType> videoTypeOut; // <-- previously mediaTypeOut
ComPtr<IMFMediaType> videoTypeIn; // <-- previously mediaTypeIn
ComPtr<IMFMediaType> audioTypeOut = nullptr;
ComPtr<IMFMediaType> audioTypeIn = nullptr;
Next, configure the output audio type compatible with your video type. Since you appear to be creating a windows media video, you will likely want to use MFAudioFormat_WMAudioV9. To ensure the channels, sample rate, and bits per sample are correct, I generally enumerate the available types and find the desired characteristics, similar to the following (error checking has been omitted):
ComPtr<IMFCollection> availableTypes = nullptr;
HRESULT hr = MFTranscodeGetAudioOutputAvailableTypes(MFAudioFormat_WMAudioV9, MFT_ENUM_FLAG_ALL, NULL, availableTypes.GetAddressOf());
DWORD count = 0;
hr = availableTypes->GetElementCount(&count)); // Get the number of elements in the list.
ComPtr<IUnknown> pUnkAudioType = nullptr;
ComPtr<IMFMediaType> audioOutputType = nullptr;
for (DWORD i = 0; i < count; ++i)
{
hr = availableTypes->GetElement(i, pUnkAudioType.GetAddressOf());
hr = pUnkAudioType.Get()->QueryInterface(IID_PPV_ARGS(audioTypeOut.GetAddressOf()));
// compare channels, sampleRate, and bitsPerSample to target numbers
{
// audioTypeOut is set!
break;
}
audioOutputType.Reset();
}
availableTypes.Reset();
if audioTypeOut was set successfully, add that type of stream to the sink and get the resulting index:
hr = sinkWriter->AddStream(audioTypeOut.Get(), &audioStreamIndex);
audioTypeOut.Reset(); // <-- audioTypeOut not needed anymore
Finally for the sink, the audio input type must be set, and that will depend on the file you are reading, and the audio source (IMFMediaSource). More on that shortly, but adding the audio input to the sink would look similar to the following:
ComPtr<IMFMediaType> audioTypeIn = nullptr; // <-- declaration from above
// NOTE: audioReader is an IMFMediaSource used to read the audio file
hr = audioReader->GetCurrentMediaType((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, audioTypeIn.GetAddressOf());
hr = sinkWriter->SetInputMediaType(_audioOutStreamIndex, audioTypeIn.Get(), nullptr);
audioTypeIn.Reset();
There are many examples available to create the audioReader (IMFMediaSource) and read samples from the file, but this one is simple and straight forward. The code is here.
Finally, writing the audio you will find to be really easy, since the sink can take the samples directly (IMFSample) that you read from the file. You get to manage the writes, but one solution is to interleave the writes (video / audio). The duration of the audio sample is handled, but you will need to rebase the timestamp. Ensure you have the correct stream index when writing to the sink.
Reading samples using and async callback:
// if you are using an async callback, the function would look similar to the following:
HRESULT OnReadAudioSample(HRESULT status, DWORD streamIndex, DWORD streamFlags, LONGLONG timestamp, IMFSample *sample)
{
// .. other code
hr = sample->SetSampleTime(timestamp - _baseRecordTime);
hr = sinkWriter->WriteSample(audioStreamIndex, sample);
// .. other code
// trigger the next asyc read...
hr = audioReader->ReadSample((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, nullptr, nullptr, nullptr, nullptr);
}
Reading samples synchronously:
// otherwise, you will only use a synchronous read
hr = audioReader->ReadSample((DWORD)MF_SOURCE_READER_FIRST_AUDIO_STREAM, 0, nullptr, &dwFlags, ×tamp, &sample);
hr = sample->SetSampleTime(timestamp - _baseRecordTime);
hr = sinkWriter->WriteSample(audioStreamIndex, sample);
hr = WriteFrame(target.get(), rtStart, rtDuration); // <-- write video frame as before
Sounds like a fun little project. Good luck, have fun, and hope this helps!
I want to program some kind of game where the player has to name loacations shown on a map. I am using the slick library.
My problem is that I need some way to get the keyboard input from the player. I tried it with InputDialog from JOptionPane but I do not really like it. I would rather have the string appear on some part of the screen. But I do not have any idea how I can read from the keyboard directly into a variable that should be drawn on the screen. I thought that it would be possible to use streams but if I try to get some examples, they are always about reading from files and I do not know how to use that for reading from keyboard.
String answer;
public void render(GameContainer gameContainer, StateBasedGame sbGame, Graphics g){
g.drawString(answer, 50, 50);
}
public void update(GameContainer gameContainer, StateBasedGame sbGame, int delta){
//user types something which I now call "inputFromUser"
//it does not appear anywhere before the string is drawn on the screen.
answer = inputFromUser;
}
Something like a Scanner does not work for me because the user has to type that into the console, and I want him to type it "directly into the game" like it works with a textfield. (But I do not want to use a textfield.)
I have one way to accomplish that but it's fairly resource intensive. First create a global variable to keep track of the current letters. now create a new method that runs through all of the keys to check if they are down
private String totalString;
private void handelUserInput(Input input){
if(input.isKeyDown(Input.KEY_BACK)){
totalString = totalString.substring(0, totalString.length() - 1);
}
if(input.isKeyDown(Input.KEY_A)){
totalString += "a";
}
if(input.isKeyDown(Input.KEY_B)){
totalString += "b";
}
...etc
}
next create an input handler in the update loop to pass into the handle input method.
public void update(GameContainer gc, StateBasedGame sbg, int delta)throws SlickException {
Input input = gc.getInput();
handelUserInput(input);
}
and then print the string somewhere on your window in the render loop. by the way the Input class is built into slick.
I am writing a COM Server which have a plenty of Interfaces and methods. And most of the methods have the BSTR as the parameters and as local parameters used for the return. A snippet looks like
Update 5:
The real code. This fetches from bunch of Data based on a specific condition the DB to populate an array of Object.
STDMETHODIMP CApplication::GetAllAddressByName(BSTR bstrParamName, VARIANT *vAdddresses)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())
//check the Database server connection
COleSafeArray saAddress;
HRESULT hr;
// Prepare the SQL Strings dan Query the DB
long lRecCount = table.GetRecordCount();
if (lRecCount > 0)
{
//create one dimension safe array for putting details
saAddress.CreateOneDim(VT_DISPATCH,lRecCount);
IAddress *pIAddress = NULL;
//retrieve details
for(long iRet = table.MoveFirst(),iCount=0; !iRet; iRet = table.MoveNext(),iCount++)
{
CComObject<CAddress> *pAddress;
hr = CComObject<CAddress>::CreateInstance(&pAddress);
if (SUCCEEDED(hr))
{
BSTR bstrStreet = ::SysAllocString(table.m_pRecordData->Street);
pAddress->put_StreetName(bstrStreet);
BSTR bstrCity = ::SysAllocString(table.m_pRecordData->City);
pAddress->put_CityName(bstrCity);
}
hr = pAddress->QueryInterface(IID_IAddress, (void**)&pIAddress);
if(SUCCEEDED(hr))
{
saAddress.PutElement(&iCount,pIAddress);
}
}
*vAdddresses=saAddress.Detach();
}
table.Close();
return S_OK;
}
STDMETHODIMP CAddress::put_CityName(BSTR bstrCityName)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())
// m_sCityName is of CComBSTR Type
m_sCityName.Empty();//free the old string
m_sCityName = ::SysAllocString(bstrCityName);//create the memory for the new string
return S_OK;
}
The problem lies in the Memory Freeing part. The code works very fine in any Win XP machines, but when comes to WIN2K8 R2 and WIN7 the code crashes and pointing to the ::SysFreeString() as the culprit. The MSDN is not adequate to the solution.
Can anyone please help in finding the right solution?
Thanks a lot in advance :)
Update 1:
I have tried using the CComBSTR as per the suggestion in the place of raw BSTR, initialized using direct CString's and excluded the SysFreeString(). But for my trouble, on getting out of scope the system is calling the SysFreeString() which again causes the crash :(
Update 2:
With the same CComBSTR i tried to allocate using the SysAllocString() , the problem remains same :(
Update 3:
I am tired of all the options and in peace I am having only question in mind
Is it necessary to free the BSTR through SysFreeString() which was
allocated using SysAllocString()/string.AllocSysString()?
Update 4:
I missed to provide the information about the crash. When I tried to debug the COM server crashed with a error saying
"Possible Heap Corruption"
. Please help me out of here.. :(
// Now All Things are packed in to the Object
obj.Name = bstrName;
obj.Name2 = bstrname2;
I don't quite understand what do you mean by saying that things are packed since you're just copying pointers to the strings, and at the moment when you call SysFreeString obj.Name and obj.Name2 will point to an invalid block of memory. Although this code is not safe, it looks like if the source of your problem is class CFoo. You should show us more details of your code
I suggest you to use a CComBSTR class which will take a responsibility for releasing the memory.
UPDATE
#include <atlbase.h>
using namespace ATL;
...
{
CComBSTR bstrname(_T("Some Name"));
CComBSTR bstrname2(_T("Another Name"));
// Here one may work with these variables if needed
...
// Copy the local values to the Obj's member Variable
bstrname.Copy(&obj.Name);
bstrname2.Copy(&obj.Name2);
}
UPDATE2
First of all one should free bstrCity and bstrStreetName with SysFreeString or use CComBSTR instead within this block:
if (SUCCEEDED(hr))
{
BSTR bstrStreet = ::SysAllocString(table.m_pRecordData->Street);
pAddress->put_StreetName(bstrStreet);
BSTR bstrCity = ::SysAllocString(table.m_pRecordData->City);
pAddress->put_CityName(bstrCity);
// SysFreeString(bstrStreet)
// SysFreeString(bstrCity)
}
Consider to amplify the loop's condition !iRet with iCount < lRecCount.
for(...; !iRet /* && (iCount < lRecCount) */; ...)
Also, here:
m_sCityName = ::SysAllocString(bstrCityName);
you allocate memory but never release it since internally CComBSTR& operator = (OLESTR ..) allocates a new storage itself. One should rewrite is as follows:
m_sCityName = bstrCityName;
Everything else, looks good for me
UPDATE3
Well, Heap corruption is often a consequence of writing some values outside of the allocated memory block. Say you allocate an array of length 5 and put some value to the 6th position
Finally I have found the real reason for the Heap Corruption that happened in the code.
The put_StreetName/put_CityName of the IAddress/CAddress is designed in a following way.
STDMETHODIMP CAddress::put_CityName(BSTR bstrCityName)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())
m_sCityName.Empty();
TrimBSTR(bstrCityName);
m_sCityName = ::SysAllocString(bstrCityName);
return S_OK;
}
BSTR CAddress::TrimBSTR(BSTR bstrString)
{
CString sTmpStr(bstrString);
sTmpStr.TrimLeft();
sTmpStr.TrimRight();
SysReAllocString(&bstrString,sTmpStr); // The Devilish Line
}
The Devilish Line of code is the real culprit that caused the Memory to go hell.
What caused the trouble?
In this line of code, the BSTR string passed as a parameter is from another application and the real memory is in another realm. So the system is trying to reallocate teh string. Either succeed or not, the same is tried to cleared off from the memory in original application/realm, thus causing a crash.
What still unsolved?
Why the same piece of code doesn't crashed a single time in Win XP and
older systems? :(
Thanks for all who took their time to answer and solve my problem :)