similar to: readBin is much slower for raw input than for a file

Dear all, The version of readBin() in R-devel includes a use of match(), through `%in%`, which can affect its performance significantly. By using primitives instead of the rather expensive call to match(), I reduce the time spent inside readBin() by more than 30% in some of my code (part of the tractor.base package). A simple patch that does this is given below. This passes "make

Dear all, I see from some previous threads that support for 64-bit integers in R may be an aim for future versions, but in the meantime I'm wondering whether it is possible to read in integers of greater than 32 bits at all. Judging from ?readBin, it should be possible to read 8-byte integers to some degree, but it is clearly limited in practice by R's internally 32-bit integer type:

Dear R-List, I am working with binary data that I want to store in a PostgreSQL DataBase. I decided to use a TXT field. I read my binary file with readBin function, I succeed in my data storage in the database but I have some trouble to extract the data : the correct amount of bytes is stored in the TXT field but when I access to the data, the extracted dataframe is truncated !

Hi, A piece of my code that uses readBin() to read a certain file type is behaving strangely with R 2.7.0. This seems to be because of a failure to match() strings after using rawToChar() when the original was terminated with a "\0" character. Direct equality testing with == still works as expected. I can reproduce this as follows: > x <- "foo" > y <-

Hi, FYI, I just notice that on Windows (but not Linux) it is orders of magnitude (below it's 50x) faster to serialize() and object to a temporary file and then read it back, than to serialize to an object directly. This has for instance impact on how fast digest::digest() can provide a checksum. Example: x <- 1:1e7; t1 <- system.time(raw1 <- serialize(x, connection=NULL));

Hello! I have problems with using of "readBin" to read files, which was written in C with "fwrite". In the C-File there is the following Code: fwrite(MyitINI,sizeof(itINItype),1,outfile); where MyitINI is a structure of the following form typedef struct{ int KernelFileSave; /* Determined, if Systemmatrix saved or not.*/ char KernelFileName[200]; /* A-Matrix name

R-devel: I am encountering a consistency issue using socketConnection and readBin with *non-blocking* connections on Unix and Windows XP (no Vista to test). I am a bit confused by the behavior of *non-blocking* connections under Windows specifically. When calling readBin on a non-blocking connection when there is no data to read on the socket, the connection under Unix will return a vector of

Hi, I'm running into more issues when reading data from a gzfile connection. If I read the data sequentially with successive calls to readBin(), the data I get looks ok. But if I call seek() between the successive calls to readBin(), I get corrupted data. Here is a (hopefully) reproducible example. See my sessionInfo() at the end (I'm not on Windows, where, according to the man page,

I would like to use readBin to read a binary data file. Most of the data is 4-byte floating point but, for some reason, only double precision appears to be offered. I tried fVariable=readBin(iFile,what=single()); and got 35.87879 which looks believable except that the correct value is 3.030303. I then tried fVariable=readBin(iFile,what=single(),4); and got [1] 3.831111e+10 6.657199e+10

I think it would be helpful if readBin checked that its endian argument is a legal value. Why? I was reviewing some of our code and noticed that the author had readBin(..., endian="network") and never having heard of "network", I looked at the man page for readBin, and it hadn't heard of "network" either. Not good. I then looked at the R code for readBin, which

Hi, The man page for readBin has a small typo: --- a/src/library/base/man/readBin.Rd +++ b/src/library/base/man/readBin.Rd @@ -58,7 +58,7 @@ writeBin(object, con, size = NA, endian \code{readBin} and \code{writeBin} read and write C-style zero-terminated character strings. Input strings are limited to 10000 - characters. \code{\link{readChar}} and \code{\code{writeChar}} +

I have been trying to use the gunzip function in the R.utils package. It opens a connection to a gzfile, uses readBin to read from that connection, and then uses writeBin to write out the raw data to a new file. This works as expected under linux/mac, but under Windows, I get: Error in readBin(inn, what= raw(0), size = 1, n=BFR.SIZE) : negative length vectors are not allowed A simple

Hi folks: This may be a stupid question, but I cannot seem to find a way to tell readBin that I want to read 2-byte integers from the connection. The input file is 150,720 bytes long containing 75,360 short (2-byte) integers. But specifying "integer" or "int" for what in readBin only returns me a vector of length 37680, leading me to believe that sizeof(integer) or

Hi, The latest version of R had some changes to functions "readbin() and writeBin() [which] now support raw vectors as well as filenames and connections.". As a result I am working on retiring "raw2bin" and "bin2raw" functions from "caTools" package which do exactly the same. Thanks to Prof. Ripley for bringing this change to my attention. Which brings me

Full_Name: Ken Yap Version: 1.6.1 OS: Linux (SuSE 8.0) Submission from: (NULL) (129.78.64.5) I'm trying to copy a file using readBin and writeBin. (The reason is to be able to pipe PostScript or PDF output to a socket later, this is just an experiment.) I do: zz <- file("foo.ps", "rb") r <- readBin(zz, character(), 1000000) yy <- file("bar.ps",

Posting for a friend Begin forwarded message: From: "Geier, Florian" <florian.geier08@imperial.ac.uk<mailto:florian.geier08@imperial.ac.uk>> Subject: Fwd: readBin fails to read large files Date: September 1, 2011 4:10:53 PM GMT+01:00 To: Begin forwarded message: Date: 1 September 2011 16:01:45 GMT+01:00 Subject: readBin fails to read large files Dear all, I am trying

Hello, With the help of "seek" I can start "readBin" from any byte offset within my file that I deem appropriate. What I would like to do is to be able to define the endpoint of that read as well. Is there any solution to that already out there? Thanks for any hints, Joh

I found that seek(..., origin = 'current', ...) and readBin(..., what = 'integer', ...) or 'int' do not work correctly. Did anyone have the same experience?

I have a binary file which is an image with multiple bands, arranged in BSQ format such that R, B and G are all N x M sized matrices (corresponding to Red, Blue and Green colors respectively). The BSQ file arranges the data as [R, B, G], so to access the B matrix, I have to read forward N x M + 1 number of samples. Is there a fast way to define a variable as the B matrix exclusively (e.g. Can I

Hello, I'm wondering if I can get some help with reading Fortran binary "unformatted" output files into R. The Fortran output files were generated in Ubuntu 10.04 LTS using gfortran4.4, on a 32bit Intel Core 2 Duo 3.16 GHz machine, with little-endian and record marker lengths equal to 4. The machine I'm currently trying to read this Fortran output file is a Macbook Pro