Search Results

Search found 4304 results on 173 pages for 'bytes'.

Page 129/173 | < Previous Page | 125 126 127 128 129 130 131 132 133 134 135 136  | Next Page >

• Which is faster in memory, ints or chars? And file-mapping or chunk reading?

  - by Nick

  Okay, so I've written a (rather unoptimized) program before to encode images to JPEGs, however, now I am working with MPEG-2 transport streams and the H.264 encoded video within them. Before I dive into programming all of this, I am curious what the fastest way to deal with the actual file is. Currently I am file-mapping the .mts file into memory to work on it, although I am not sure if it would be faster to (for example) read 100 MB of the file into memory in chunks and deal with it that way. These files require a lot of bit-shifting and such to read flags, so I am wondering that when I reference some of the memory if it is faster to read 4 bytes at once as an integer or 1 byte as a character. I thought I read somewhere that x86 processors are optimized to a 4-byte granularity, but I'm not sure if this is true... Thanks!

  Read the article

• Is the "message" of an exception culturally independent?

  - by Ray Hayes

  In an application I'm developing, I have the need to handle a socket-timeout differently from a general socket exception. The problem is that many different issues result in a SocketException and I need to know what the cause was. There is no inner exception reported, so the only information I have to work with is the message: "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond" This question has a general and specific part: is it acceptable to write conditional logic based upon the textual representation of an exception? Is there a way to avoid needing exception handling? Example code below... try { IPEndPoint endPoint = null; client.Client.ReceiveTimeout = 1000; bytes = client.Receive(ref endPoint); } catch( SocketException se ) { if ( se.Message.Contains("did not properly respond after a period of time") ) { // Handle timeout differently.. } }

  Read the article

• MS SQL 2005 - Understanding ouput of DBCC SHOWCONTIG

  - by user169743

  I'm seeing some slow performance on a MS SQL 2005 database. I've been doing some research regarding MS SQL performance but I'm having difficulty fully understanding the output of SHOWCONTIG and would be very grateful if someone could have a look and offer some suggestions to improve performance. TABLE level scan performed. Pages Scanned................................: 19348 Extents Scanned..............................: 2427 Extent Switches..............................: 3829 Avg. Pages per Extent........................: 8.0 Scan Density [Best Count:Actual Count].......: 63.16% [2419:3830] Logical Scan Fragmentation ..................: 8.40% Extent Scan Fragmentation ...................: 35.15% Avg. Bytes Free per Page.....................: 938.1 Avg. Page Density (full).....................: 88.41%

  Read the article

• When will a TCP network packet be fragmented at the application layer?

  - by zooropa

  When will a TCP packet be fragmented at the application layer? When a TCP packet is sent from an application, will the recipient at the application layer ever receive the packet in two or more packets? If so, what conditions cause the packet to be divided. It seems like a packet won't be fragmented until it reaches the Ethernet (at the network layer) limit of 1500 bytes. But, that fragmentation will be transparent to the recipient at the application layer since the network layer will reassemble the fragments before sending the packet up to the next layer, right?

  Read the article

• Why does my git push hang after successfully pushing?

  - by John

  On a newly set up ssh git repo, whenever I push, I get normal output like this: ? git push Counting objects: 15, done. Delta compression using up to 4 threads. Compressing objects: 100% (9/9), done. Writing objects: 100% (9/9), 989 bytes, done. Total 9 (delta 7), reused 0 (delta 0) It happens very quickly, and the changes are immediately available on the server repo. But the output hangs there for about a minute, and then finishes with: To [email protected]:baz.git c8c391c..1de5e80 branch_name -> branch_name If I control-c before it finishes, everything seems to continue to be normal and healthy, locally and remotely. What is it doing while hanging? Is something configured incorrectly on the server side?

  Read the article

• How to compute power spectrum from 2D FFT

  - by user1452954

  I've encounter a problem when doing my lab assignment, not sure how to implement this: Use fft2 on a gray image and to do Fourier transform and then compute the power spectrum. This is my code so far: >> Pc = imread('pckint.jpg'); >> whos Pc; Name Size Bytes Class Attributes Pc 256x256 65536 uint8 >> imshow(Pc); >> result = fft2(Pc); My question is from the result. How to computer power spectrum?

  Read the article

• GetDiskFreeSpaceEx in winCE 5.0 emulator?

  - by vidhyarthi

  Hi, I am trying to use GetDiskFreeSpaceEx in wince5.0 emulator. This is the following code I have written. ULARGE_INTEGER notused, totalBytes, freeBytes; GetDiskFreeSpaceEx(_T("\\Windows"),&notused,&totalBytes,&freeBytes); printf(" Error in disk %d ", GetLastError()); printf(" values = notused %d,totalBytes %d,freeBytes %d",notused,totalBytes,freeBytes); *Output * 14540 PID:3db620e TID:3e5c83e Error in disk 0 14540 PID:3db620e TID:3e5c83e values = notused 25987296,totalBytes 0,freeBytes 26234880 The total bytes that I get is zero. Am I missing something or in emulator is that OK?

  Read the article

• Getting list of all existing vtables.

  - by Patrick

  In my application I have quite some void-pointers (this is because of historical reasons, application was originally written in pure C). In one of my modules I know that the void-pointers points to instances of classes that could inherit from a known base class, but I cannot be 100% sure of it. Therefore, doing a dynamic_cast on the void-pointer might give problems. Possibly, the void-pointer even points to a plain-struct (so no vptr in the struct). I would like to investigate the first 4 bytes of the memory the void-pointer is pointing to, to see if this is the address of the valid vtable. I know this is platform, maybe even compiler-version-specific, but it could help me in moving the application forward, and getting rid of all the void-pointers over a limited time period (let's say 3 years). Is there a way to get a list of all vtables in the application, or a way to check whether a pointer points to a valid vtable, and whether that instance pointing to the vtable inherits from a known base class?

  Read the article

• Java blocking socket returning incomplete ByteBuffer

  - by evandro-carrenho

  I have a socketChannel configured as blocking, but when reading byte buffers of 5K from this socket, I get an incomplete buffer sometimes. ByteBuffer messageBody = ByteBuffer.allocate(5*1024); messageBody.mark(); messageBody.order(ByteOrder.BIG_ENDIAN); int msgByteCount = channel.read(messageBody); Ocasionally, messageBody is not completely filled and channel.read() does not return -1 or an exception, but the actual number of bytes read (which is less than 5k). Has anyone experienced a similar problem?

  Read the article

• How to create an ARGB_8888 pixel value?

  - by vidstige

  Say I want to create an array of pixel values to pass into the createBitmap method described here. I have three int values r, g, b in the range 0 - 0xff. How do I transform those into a opaque pixel p? Does the alpha channel go in the high byte or the low byte? I googled up the documentation but it only states that: Each pixel is stored on 4 bytes. Each channel (RGB and alpha for translucency) is stored with 8 bits of precision (256 possible values.) This configuration is very flexible and offers the best quality. It should be used whenever possible. So, how to write this method? int createPixel(int r, int g, int b) { retrurn ? }

  Read the article

• Oracle: TABLE ACCESS FULL with Primary key?

  - by tim

  There is a table: CREATE TABLE temp ( IDR decimal(9) NOT NULL, IDS decimal(9) NOT NULL, DT date NOT NULL, VAL decimal(10) NOT NULL, AFFID decimal(9), CONSTRAINT PKtemp PRIMARY KEY (IDR,IDS,DT) ) ; SQL>explain plan for select * from temp; Explained. SQL> select plan_table_output from table(dbms_xplan.display('plan_table',null,'serial')); PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------- --------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| --------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 61 | 2 (0)| | 1 | TABLE ACCESS FULL| TEMP | 1 | 61 | 2 (0)| --------------------------------------------------------------- Note ----- - 'PLAN_TABLE' is old version 11 rows selected. SQL server 2008 shows in the same situation Clustered index scan. What is the reason?

  Read the article

• Writing Strings to files in python

  - by Leif Andersen

  I'm getting the following error when trying to write a string to a file in pythion: Traceback (most recent call last): File "export_off.py", line 264, in execute save_off(self.properties.path, context) File "export_off.py", line 244, in save_off primary.write(file) File "export_off.py", line 181, in write variable.write(file) File "export_off.py", line 118, in write file.write(self.value) TypeError: must be bytes or buffer, not str I basically have a string class, which contains a string: class _off_str(object): __slots__ = 'value' def __init__(self, val=""): self.value=val def get_size(self): return SZ_SHORT def write(self,file): file.write(self.value) def __str__(self): return str(self.value) Furthermore, I'm calling that class like this: def write(self, file): for variable in self.variables: variable.write(file) I have no idea what is going on. I've seen other python programs writing strings to files, so why can't this one? Thank you very much for your help.

  Read the article

• Problem with increment in inline ARM assembly

  - by tech74

  Hi , i have the following bit of inline ARM assembly, it works in a debug build but crashes in a release build of iphone sdk 3.1. The problem is the add instructions where i am incrementing the address of the C variables output and x by 4 bytes, this is supposed to increment by the size of a float. I think when i increment at some such stage i am overwriting something, can anyone say which is the best way to handle this Thanks C code that the asm is replacing, sum,output and x are all floats for(int i = 0; i< count; i++) sum+= output[i]* (*x++) asm volatile( ".align 4 \n\t" "mov r4,%3 \n\t" "flds s0,[%0] \n\t" "0: \n\t" "flds s1,[%2] \n\t" //"add %3,%3,#4 \n\t" "flds s2,[%1] \n\t" //"add %2,%2,#4 \n\t" "subs r4,r4, #1 \n\t" "fmacs s0, s1, s2 \n\t" "bne 0b \n\t" "fsts s0,[%0] \n\t" : : "r" (&sum), "r" (output), "r" (x),"r" (count) : "r0","r4","cc", "memory", "s0","s1","s2" );

  Read the article

• I just can't figure out strcat.

  - by Anonymous

  I know I shouldn't be using that function, and I don't care. Last time I checked the spec for strcat, it said something along the lines of updating the first value as well as returning the same. Now, this is a really stupid question, and I want you to explain it like you're talking to a really stupid person. Why won't this work? char* foo="foo"; printf(strcat(foo,"bar")); EDIT: I don't know the difference between char[] and char*. How would I allocate a string of 255 characters? EDIT 2: OK, OK, so char[number] allocates a string of that many bytes? Makes sense. Thanks.

  Read the article

• How big can a SQL Server row be before it's a problem?

  - by John Leidegren

  Occasionally I run into this limitation using SQL Server 2000 that a row size can not exceed 8K bytes. SQL Server 2000 isn't really state of the art, but it's still in production code and because some tables are denormalized that's a problem. However, this seems to be a non issue with SQL Server 2005. At least, it won't complain that row sizes are bigger than 8K, but what happens instead and why was this a problem in SQL Server 2000? Do I need to care about my rows growing? Should I try and avoid large rows? Are varchar(max) and varbinary(max) a solution or expensive, in terms of size in database and/or CPU time? Why do I care at all about specifying the length of a particular column, when it seems like it's just a matter of time before someones going to hit that upper limit?

  Read the article

• Ignoring "Content is not allowed in trailing section" SAXException

  - by Paul J. Lucas

  I'm using Java's DocumentBuilder.parse(InputStream) to parse an XML document. Occasionally, I get malformed XML documents in that there is extra junk after the final > that causes a SAXException: Content is not allowed in trailing section. (In the cases I've seen, the junk is simply one or more null bytes.) I don't care what's after the final >. Is there an easy way to parse an entire XML document in Java and have it ignore any trailing junk? Note that by "ignore" I don't simply mean to catch and ignore the exception: I mean to ignore the trailing junk, throw no exception, and to return the Document object since the XML up to an including the final > is valid.

  Read the article

• Looking at the C++ new[] cookie. How portable is this code?

  - by carleeto

  I came up with this as a quick solution to a debugging problem - I have the pointer variable and its type, I know it points to an array of objects allocated on the heap, but I don't know how many. So I wrote this function to look at the cookie that stores the number of bytes when memory is allocated on the heap. template< typename T > int num_allocated_items( T *p ) { return *((int*)p-4)/sizeof(T); } //test #include <iostream> int main( int argc, char *argv[] ) { using std::cout; using std::endl; typedef long double testtype; testtype *p = new testtype[ 45 ]; //prints 45 std::cout<<"num allocated = "<<num_allocated_items<testtype>(p)<<std::endl; delete[] p; return 0; } I'd like to know just how portable this code is.

  Read the article

• Malware on a client's website - Ideas?

  - by Jeriko

  We recently got a call from one of our clients, complaining that their site has some "strange looking code" at the bottom of the page. We checked out the source code, and discovered that about 800 bytes of malicious javascript code had been appended to the templates/master file, after the </html> tag. I won't post said code because it looked particularly nasty. As far as I can tell, there would be no way for this file to be edited in any way, unless someone had direct access to the server and/or FTP login details. The actual file itself has been modified, so that rules out any kind of SQL attack. Besides a person physically gaining credentials and hand-modifying this file, would there be any other logical explaination for what happened? Has anyone else had experience with something like this happening?

  Read the article

• Cache bandwidth per tick for modern CPUs

  - by osgx

  Hello What is a speed of cache accessing for modern CPUs? How many bytes can be read or written from memory every processor clock tick by Intel P4, Core2, Corei7, AMD? Please, answer with both theoretical (width of ld/sd unit with its throughput in uOPs/tick) and practical numbers (even memcpy speed tests, or STREAM benchmark), if any. PS it is question, related to maximal rate of load/store instructions in assembler. There can be theoretical rate of loading (all Instructions Per Tick are widest loads), but processor can give only part of such, a practical limit of loading.

  Read the article

• Programatically determining file "size on disk" in advance

  - by porkchop

  I need to know how big a given in-memory buffer will be as an on-disk (usb stick) file before I write it. I know that unless the size falls on the block size boundary, its likely to get rounded up, e.g. a 1 byte file takes up 4096 bytes on-disk. I'm currently doing this using GetDiskFreeSpace() to work out the disk block size, then using this to calculate the on-disk size like this: GetDiskFreeSpace(szDrive, &dwSectorsPerCluster, &dwBytesPerSector, NULL, NULL); dwBlockSize = dwSectorsPerCuster * dwBytesPerSector; if (dwInMemorySize % dwBlockSize != 0) { dwSizeOnDisk = ((dwInMemorySize / dwBlockSize) * dwBlockSize) + dwBlockSize; } else { dwSizeOnDisk = dwInMemorySize; } Which seems to work fine, BUT GetDiskFreeSpace() only works on disks up to 2GB according to MSDN. GetDiskFreeSpaceEx() doesn't return the same information, so my question is, how else can I calculate this information for drives 2GB? Is there an API call I've missed? Can I assume some hard values depending on the overall disk size?

  Read the article

• Swap byte 2 and 4 from integer

  - by czar x

  I had this interview question - Swap byte 2 and byte4 within an integer sequence. Integer is a 4byte wide i.e. 32 bits My approach was to use char *pointer and a temp char to swap the bytes. For clarity i have broken the steps otherwise an character array can be considered. unsigned char *b2, *b4, tmpc; int n = 0xABCD; b2 = &n; b2++; b4 = &n; b4 +=3; ///swap the values; tmpc = *b2; *b2 = *b4; *b4 = tmpc; Any other methods?

  Read the article

• convert flv to mp3 with Java

  - by krial

  Hi, I'm pretty new in developing programs in Java. I'm currently writing a program that converts a flv video into mp3. I have already written such a program in Visual Studio.net C#, but the Problem is, that it isn't cross platform compatible... I used the ffmpeg binary to convert the video into mp3, but I can't find ffmpeg binaries for Mac and Linux. (if so, I could start the specific binaries from java, depending on the OS) So I tried to convert the video with Xuggle, but the final mp3 has 0 bytes. My current code is the following: IMediaReader reader = ToolFactory.makeReader("video.flv"); reader.addListener(ToolFactory.makeWriter("music.mp3", reader)); while (reader.readPacket() == null) do {} while(false); Thanks in advance. p.s sorry for my bad english

  Read the article

• How it is called when write or read return less that requested?

  - by Vi

  What term should I use to describe situations (or bugs in software) caused by read, write, send, recv doing less work than expected? For example, write(fd, "123456", 6); may return 3 and we need to write "456" to finish our work. I expect any good program should do all their reads and writes in a loop until without relying that write will write everything. Am I right? /* Implemented simple FUSE filesystem which only allows reading and writing with small buffers, very often returning that it is written less bytes that in a buffer. Some programs work, some not. Are them buggy? */

  Read the article

• What does this C++ code mean

  - by Markus Orreilly

  I was trying to understand how webkit parses urls, and I'm having a hard time making heads or tails of this: Vector<char, 4096> buffer(fragmentEnd * 3 + 1); This line is on line 1214 (you can see it here: http://trac.webkit.org/browser/trunk/WebCore/platform/KURL.cpp#L1214). I get that it's making a vector of type char, with each entry being an array of char 4096 bytes large, but I don't get the buffer(fragmentEnd * 3 + 1) part. I think that it confuses me most b/c I can't find where the buffer variable is instantiated anywhere (shouldn't it be something more like Vector<char, 4096> buffer = new Vector<char, 4096>(...)? Thanks in advance

  Read the article

• Storing objects in STL vector - minimal set of methods

  - by osgx

  Hello What is "minimal framework" (necessary methods) of object, which I will store in STL <vector>? For my assumptions: #include <vector> #include <cstring> using namespace std; class Doit { private: char *a; public: Doit(){a=(char*)malloc(10);} ~Doit(){free(a);} }; int main(){ vector<Doit> v(10); } gives *** glibc detected *** ./a.out: double free or corruption (fasttop): 0x0804b008 *** Aborted and in valgrind: malloc/free: 2 allocs, 12 frees, 50 bytes allocated.

  Read the article

< Previous Page | 125 126 127 128 129 130 131 132 133 134 135 136  | Next Page >