file-io

问题 Step1 : AssumeRole public static AWSCredentialsProvider getCredentials() { if (roleARN.length() > 0) { STSAssumeRoleSessionCredentialsProvider credentialsProvider = new STSAssumeRoleSessionCredentialsProvider .Builder(roleARN, Constants.SESSION_NAME) .withStsClient(AWSSecurityTokenServiceClientBuilder.defaultClient()) .build(); return credentialsProvider; } return new ProfileCredentialsProvider(); } Step 2 : Set Credentials to pipeline credentials = getCredentials(); pipeline.getOptions().as

问题 I create a file transfer program which upload files (huge file about 4gb) using html5 chunking. each chunk is sized of 100MB (I just choose this for no reason, as I try use 10MB, it does not really have any difference as far as I can tell). It upload correctly each chunk. but at the end of finish uploading, I try to merge the file back into 1 piece, but it takes so much time. If I try to refresh the web ui for the uploader, it won't work until it finish merging. my merge code something like

问题 I'm trying to understand Linux (UNIX) low-level interfaces and as an exercise want to write a code which will copy a file with holes into a new file (again with holes). So my question is, how to read from the first file not till the first hole, but till the very end of the file? If I'm not mistaken, read() returns 0 when reaches the first hole(EOF). I was thinking about seeking right byte by byte and trying to read this byte, but then I have to know the number of holes in advance. 回答1: If by

问题 I'm attempting to identify the blocks that are tied to a specific file and write zeros to them. I've found several methods that do this to the free space on a disk, but so far I haven't found any slid suggestions for doing the following: identify the blocks for a file Write zeros to those blocks. The purpose of this is for a virtualized system. This system has the ability to dedupe blocks that are identified as being the same. This is used to reduce space used by the guest OSes on the drive.

问题 I'm having a strange issue with the package numpy.genfromtxt. I use it to read a data file with a number of columns (available here) but these are not being unpacked even when unpack is set to True . Here's a MWE : import numpy as np f_data = np.genfromtxt('file.dat', dtype=None, unpack=True) print f_data[3] (237, 304.172, 2017.48, 15.982, 0.005, 0.889, 0.006, -2.567, 0.004, 1.205, 0.006) (I use dtype=None because the file can have strings scattered around) As you can see it returns a line

问题 I'm having a strange issue with the package numpy.genfromtxt. I use it to read a data file with a number of columns (available here) but these are not being unpacked even when unpack is set to True . Here's a MWE : import numpy as np f_data = np.genfromtxt('file.dat', dtype=None, unpack=True) print f_data[3] (237, 304.172, 2017.48, 15.982, 0.005, 0.889, 0.006, -2.567, 0.004, 1.205, 0.006) (I use dtype=None because the file can have strings scattered around) As you can see it returns a line

问题 I have to duplicate a FILE* in C on Mac OS X (using POSIX int file descriptors all the way is unfortunately out of question), so I came up with the following function: static FILE* fdup(FILE* fp, const char* mode) { int fd = fileno(fp); int duplicated = dup(fd); return fdopen(duplicated, mode); } It works very well, except it has that small ugly part where I ask for the file mode again, because fdopen apparently can't determine it itself. This issue isn't critical, since basically, I'm just

问题 I have to duplicate a FILE* in C on Mac OS X (using POSIX int file descriptors all the way is unfortunately out of question), so I came up with the following function: static FILE* fdup(FILE* fp, const char* mode) { int fd = fileno(fp); int duplicated = dup(fd); return fdopen(duplicated, mode); } It works very well, except it has that small ugly part where I ask for the file mode again, because fdopen apparently can't determine it itself. This issue isn't critical, since basically, I'm just

问题 I am making a text editor and for editing a file I really need some sort of way to only read certain bytes from a file, which I've achieved using fs.createReadStream uisng the start and end options. I also need to replace certain bytes in the file. I am not sure how this can be done. So far the best solution I've come up is to read the file using a stream and then write to a new file, when I come across the bytes I'm looking for I write my new content instead, thus replacing the old stuff

问题 I am making a text editor and for editing a file I really need some sort of way to only read certain bytes from a file, which I've achieved using fs.createReadStream uisng the start and end options. I also need to replace certain bytes in the file. I am not sure how this can be done. So far the best solution I've come up is to read the file using a stream and then write to a new file, when I come across the bytes I'm looking for I write my new content instead, thus replacing the old stuff