how can I get metadata of a pdf document(e.g. title, author, creation date etc) by using mupdf library? There is not enough documentation to find out this functionality. Comments are not sufficient, too. Most probably, there is a functionality for this purpose but it is hard to find under these circumstances. The following code is what I have so far.
char info[64];
globals *glo = get_globals(env, thiz);
fz_meta(glo->doc, FZ_META_INFO, info, sizeof(info));
I have used FZ_META_INFO tag, but it doesn't work. I didn't get any info, just empty. I have checked that it has metadata. Any help is appreciated.
EDIT:
Target Android sdk:20
Min Android sdk:15
Mupdf version: 1.6
ndk: r10c
Development OS: Ubuntu 12.04
In what sense 'doesn't work' ? Throws an error ? Crashes ? Are you certain the PDF file you are using has any 'Info' metadata ?
What is the version of MuPDF ? What platform are you using ?
You need to set the relevant key in the buffer you pass to fz_meta before you call fz_mets, I notice you aren't doing that.
See win_main.c at around line 487, after you get past the macro this resolves to
char info[256]
sprintf(info, "Title");
fz_meta(doc, FZ_META_INFO, info, 256);
On return 'info' will contain the metadata associated with the Title key in the dictionary.
When in doubt, build the sample app and follow it in a debugger......
If the proper casting allow to send the key,
this casting is NOT correct to receive back a char*.
Exemple;
Proper casting to send a request
char buff[2048];
strcpy(buff,"CreationDate")
if (fz_meta(ctx,doc,FZ_META_INFO,&buff,2048)) {
buff[0] = 0;
}
Will:
find the key,
convert utf8
then will crash when copyback of the result
Proper casting to receive a request
char buff[2048];
strcpy(buff,"CreationDate")
if (fz_meta(ctx,doc,FZ_META_INFO,buff,2048)) {
buff[0] = 0;
}
Will crash during dict scanning.
looks really like a bug!
I confirm that modifying original source
info = pdf_dict_gets(ctx, info, (char *)ptr);
is the way to go. (even if strange that nobody else find it while writing code, because Meta are useful features frequently used
Related
string docuAddr = #"C:\Users\psimmon\source\repos\PDFTESTAPP\PDFTESTAPP\TempForms\forms-www.courts.state.co.us-Forms-PDF-JDF1117.pdf";
byte[] bytes = Encoding.Unicode.GetBytes(docuAddr);
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(bytes, true);---blows here
PdfLoadedForm myForm = loadedDocument.Form;
PdfLoadedFormFieldCollection fields = myForm.Fields;
not sure what I have done wrong here, but the PDF file is opening, either in a browser or a fileexployer window. so it has to be me, guessed at most of this, all you very smart folks, I could use your gray matter. forgive my stupidity.
The reported exception “could not find valid signature (%PDF-)” may occurs due to the file is not a PDF document. We suspect it seems the other format files are saved with the “.pdf” extension. We could not open and repair this type of document on our end, we have already added the details in our documentation,
Please find some of the following corrupted error messages that cannot be repaired:
UG: https://help.syncfusion.com/file-formats/pdf/open-and-save-pdf-file-in-c-sharp-vb-net#possible-error-messages-of-invalid-pdf-documents-while-loading
If you want to find this type of corrupted document, Syncfusion PDF Library provides support to check and report whether the existing PDF document is corrupted or not with corruption details and structure-level syntax errors.
UG: https://help.syncfusion.com/file-formats/pdf/working-with-document#find-corrupted-pdf-document
Blog: https://www.syncfusion.com/blogs/post/how-to-find-corrupted-pdf-files-in-c-sharp.aspx
KB: https://www.syncfusion.com/kb/9686/how-to-identify-the-corrupted-pdf-document-using-c-and-vb-net
Basically, I've been developing a bot for several weeks now using the discord.js library and recently encountered a small but crucial issue. Essentially when I declare my argument, I also made it so that the message content (message.content) would be capitalized using .toUpperCase(). Essentially in doing so regardless of the type of prefix you would enter (symbol wise) it would all be read by the program as valid.
For example only: !help - should work, however if I would enter .help, it would also be read as valid.
In any case, here's the code. I appreciate all the help!
bot.on('message', message =>{
let args = message.content.toUpperCase().substring(PREFIX.length).split(" ");
const sender = message.member;
switch(args[0])
{
case 'HELP':
message.reply("I've sent you some documentation on all the commands that you can use...").then(d_msg => {d_msg.delete(3000); });
message.delete(3000);
const attachment = new Attachment('./UtilityBot_Documentation.txt')
message.author.send('[Education] Bot - Documentation');
message.author.send(attachment);
break;
}
})
The discord.js tutorial covers an extremely similar problem to what you're trying to do. I recommend you check it out. The page I linked in specific is doing a very similar thing to you, but it's worth giving the whole thing a read through if you haven't done so already. In general, I would include the following line just above where you established args.
if (!message.content.startsWith(PREFIX)) return;
What I'm doing here is saying if the message does not start with the prefix, stop running until a new message is sent. I might be missing something, but certainly check out the tutorial. It's really well written.
https://discordjs.guide/creating-your-bot/commands-with-user-input.html#basic-arguments
We have developed the tools to read the emails from the Domino mailboxes and write those into the separate file in local disk(Its look like a backup). Recently we have created a new domino 9 test environment with our lab. But, our tools not working properly with our new domino work environment. To identify the problem about this issue, I have added some debug logs and it seems to look like the control hanged with the function "NAMELookup2". Here, I have added the code snippet,
DHANDLE hLookup;
char *pLookup;
if (NAMELookup2("Local", 0, 1, "$users", 1, dominoUser, 2, "FullName", &hLookup) == NOERROR) // hunged with this line
{
pLookup = (char *) OSLockObject(hLookup);
}
The same tool working fine with our other test environment. So, I think there is no problem with the code. I suspect that maybe the problem with our new work environment setup creation, or maybe missed to provide some kind permission to the users, or maybe I missed to add the mailboxes somewhere, etc.
Note:
I have run the tool with admin privilege user.
It would be great if anyone gives some direction on this.
Thanks,
See this NAMELookup2 page for reference. The function is declared as:
STATUS LNPUBLIC NAMELookup2(const char far *ServerName, DWORD Flags,
WORD NumNameSpaces, const char far *NameSpaces,
WORD NumNames, const char far *Names,
WORD NumItems, const char far *Items,
DHANDLE far *rethBuffer);
where NumItems is the number of null-terminated item names starting at the Items address. The code snippet in your question is passing a single item name ("FullName"), but is setting NumItems to 2. That is clearly wrong and could explain the hang. NumItems should be 1.
I am also suspicious of the ServerName argument. The documentation recommends passing NULL when you want to do a local lookup. Passing "Local" may be another way to accomplish the same, but you need to change your code in any case. I recommend changing the first argument to NULL.
My goal is to write a c-dll (compiled with MinGW) that is able to search for certain models of USB sticks connected to the computer and deliver the serial number, the vendor ID, the product ID and the drive letter.
I have searched on the internet for several hours know but could not find an approach that works for me.
I am using the Setup Api to get a list of all connected USB devices. For each USB device I get a path that looks like this:
\?\usb#vid_048d&pid_1172#00000020370220#{a5dcbf10-6530-11d2-901f-00c04fb951ed}
From that string I can get the vendor ID, product ID and the serial number I am looking for.
My problem is now to determine the drive letter of the USB drive that is related to this device path.
During my internet research I found the following approach multiple times (for example here http://oroboro.com/usb-serial-number/):
Once the device path is found, the USB drive must be opened by CreateFile. The handle returned by that function can be used to get the device number by function DeviceIOControl with IOCTL_STORAGE_GET_DEVICE_NUMBER.
After that, the CreateFile function could be used to open each drive letter (starting from a:) and try to get the device number the same way like described above. Once the same device number is found again, the relation between device path and drive letter is made.
My Problem is that the IOCTL_STORAGE_GET_DEVICE_NUMBER call is not working. The DeviceIOControl function returns error code 50 which means "The request is not supported".
I am not able to create a link between the device path of a USB stick and the drive letter. I have tried several IOCTL_STORAGE and IOCTL_VOLUME calls but none worked for the USB sticks I tried.
I also read in another Forum that people had problems with the results of the DeviceIOControl function. It was returning the desired result on some PCs while it was making trouble on others.
Is there another way of achieving my goal?
I already had a look into the registry where I can also find the desired data. But again I had the problem to create the connection between device path and drive letter.
I would not like to use the WMI. I have read that it is still not really supported by MinGW.
I have a implementaion for all this with C# where it is really easy to get the desired information, but now I also need one that is created with unmanaged code and can be used to replace a c-dll also included in Delphi projects.
I would appreciate any suggestions for a solution to my problem.
Best regards,
Florian
And here the code if someone is interested. The position with this comment "//HERE IS WHERE I WOULD LIKE TO GET THE DEVICE NUMBER!!!" is where the request of the device number would be used if it would work.
typedef struct ty_TUSB_Device
{
PSP_DEVICE_INTERFACE_DETAIL_DATA deviceDetailData;
char devicePath[300];
}TUSB_Device;
int
GetUSBDevices (TUSB_Device *devList[], int size)
{
HANDLE hHCDev;
HDEVINFO deviceInfo;
SP_DEVICE_INTERFACE_DATA deviceInfoData;
ULONG index;
ULONG requiredLength;
int devCount = 0;
//SP_DEVINFO_DATA DevInfoData;
// Now iterate over host controllers using the new GUID based interface
//
deviceInfo = SetupDiGetClassDevs((LPGUID)&GUID_DEVINTERFACE_USB_DEVICE,
NULL,
NULL,
(DIGCF_PRESENT | DIGCF_DEVICEINTERFACE));
if (deviceInfo != INVALID_HANDLE_VALUE)
{
deviceInfoData.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
for (index=0;
SetupDiEnumDeviceInterfaces(deviceInfo,
0,
(LPGUID)&GUID_DEVINTERFACE_USB_DEVICE,
index,
&deviceInfoData);
index++)
{
SetupDiGetDeviceInterfaceDetail(deviceInfo,
&deviceInfoData,
NULL,
0,
&requiredLength,
NULL);
//allocate memory for pointer to TUSB_Device structure
devList[devCount] = malloc(sizeof(TUSB_Device));
devList[devCount]->deviceDetailData = GlobalAlloc(GPTR, requiredLength);
devList[devCount]->deviceDetailData->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
SetupDiGetDeviceInterfaceDetail(deviceInfo,
&deviceInfoData,
devList[devCount]->deviceDetailData,
requiredLength,
&requiredLength,
NULL);
//open the usb device
hHCDev = CreateFile(devList[devCount]->deviceDetailData->DevicePath,
GENERIC_WRITE,
FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL);
// If the handle is valid, then we've successfully found a usb device
//
if (hHCDev != INVALID_HANDLE_VALUE)
{
strncpy(devList[devCount]->devicePath, devList[devCount]->deviceDetailData->DevicePath, sizeof(devList[devCount]->devicePath));
//HERE IS WHERE I WOULD LIKE TO GET THE DEVICE NUMBER!!!
CloseHandle(hHCDev);
devCount++;
}
//GlobalFree(devList[devCount]->deviceDetailData);
}
SetupDiDestroyDeviceInfoList(deviceInfo);
}
return devCount;
}
I found out what my problem was. From what I read on the internet it seems there where other people having the same problems like me, so I will post my solution.
The whole point is that there are obviously different path values one can obtain for a USB device using the SetupApi. All path values can be used to get a handle to that device, but there are obviously differences about what can be done with the handle.
My failure was to use GUID_DEVINTERFACE_USB_DEVICE to list the devices. I found out that when I use GUID_DEVINTERFACE_DISK, I get a different path value that lets me request the device number. That way I am able to get the link to the drive letter.
That path value obtained with GUID_DEVINTERFACE_DISK also contains the serial number but not the vendor and product IDs. But since both path values do contain the serial, it is no problem to get them both and build the relation.
I tested the code with Windows XP, 7 and 8 and it works fine. Only the FileCreate code of the code sample above must be adjusted (replace GENERIC_WRITE by 0). Otherwise Administrator rights or compatibility mode are required.
I did not try to find out what these different GUID values really stand for. Someone with a deeper knowledge in this area could probably provide a better explanation.
Best regards,
Florian
I started to deal with ffmpeg API ( not the command prompt ) to build a movie editor, and I'm trying to find a good tutorial about how to extract keyframes from video, but I didn't find it.
Someone did it before and can write the code here?
Someone has a good tutorial about ffmpeg API?
Thank you!
In your demuxing loop, check for the AV_PKT_FLAG_KEY flag in AVPacket::flags after calling av_read_frame() with your AVFormatContext and confirming the read packet is from the correct stream of the input. Example:
AVPacket packet;
if (av_read_frame(pFormatCtx, &packet) < 0) {
break;
}
if (videoStream/* e.g. 0 or 1 */ == packet.stream_index) {
if (packet.flags & AV_PKT_FLAG_KEY) { //do something
Note that, in my experience, you sometimes need to decode up to 2 keyframes before the desired frame in order to produce a good picture.
See the doc/examples directory in the ffmpeg distribution for some API usage examples, e.g. demuxing_decoding.c. You can also reference ffmpeg.c (the source of the famous CLI) if you are brave and/or have a good IDE.