checksum

My Subversion 1.7.17 working copy is unhappy with a particular file but is unable to update it. Any attempt to update gives me the same error, even if I delete the file or delete the directory: Updating 'trunk/src/Makefile': svn: E155017: Checksum mismatch for '/Volumes/project/dev/torc/trunk/src/Makefile': expected: 78ee11ff73f3b68c903db838b6667ec3 recorded: 62bbbf4362958e3fd42470650d5b4eb6 I have read through SVN - Checksum mismatch while updating , and its two main solutions are to modify .svn/entries or to delete and restore the directory. There is nothing useful in the top-level .svn

I'd like to be able to tell whether a SQLite database file has been updated in any way. How would I go about implementing that? The first solution I think of is comparing checksums, but I don't really have any experience working with checksums. According to http://www.sqlite.org/fileformat.html SQLite3 maintains a file change counter in byte 24..27 of the database file. It is independent of the file change time which, for example, can change after a binary restore or rollback while nothing changed at all: $ sqlite3 test.sqlite 'create table test ( test )' $ od --skip-bytes 24 --read-bytes=4

Preface: I am doing a data-import that has a verify-commit phase. The idea is that: the first phase allows taking data from various sources and then running various insert/update/validate operations on a database. The commit is rolled back but a "verification hash/checksum" is generated. The commit phase is the same, but, if the "verification hash/checksum" is the same then the operations will be committed. (The database will be running under the appropriate isolation levels.) Restrictions: Input reading and operations are forward-read-once only Do not want to pre-create a stream (e.g. writing

I tried to find out how to calculate the error detection capabilities of arbitrary CRC polynomials. I know that there are various error detection capabilities that may (or may not) apply to an arbitrary polynomial: Detection of a single bit error: All CRCs can do this since this only requires a CRC width >= 1. Detection of burst errors: All CRCs can detect burst errors up to a size that equals their width. Detection of odd numbers of bit errors: CRC with polynomials with an even number of terms (which means an even number of 1-bits in the full binary polynomial) can do this. Detection of

Still learning how to use Maven , and I was wondering if there is a way to do a checksum on the generated WAR file. The Maven goal is package , and what I'm trying to achieve is to get a checksum value (of the packaged WAR file) put into a text file alongside the packaged file. Thanks in advance! Got it working with the below pom code and changing my Maven goal to verify <dependency> ... <!-- CheckSum --> <dependency> <groupId>net.ju-n.maven.plugins</groupId> <artifactId>checksum-maven-plugin</artifactId> <version>1.2</version> <exclusions> <exclusion> <groupId>org.bouncycastle</groupId>

Are there any 32-bit checksum algorithm with either: Smaller hash collision probability for input data sizes < 1 KB ? Collision hits with more uniform distribution. These relative to CRC32. I'm practically not counting on first property, because of limitation of storage space of 32 bits. But for the second ... seems there could be improvements. Any ideas ? Thanks. (I need concrete implementation, better in C, but C++/ C# or anything to start with is also OK). How about MurmurHash ? It is said , that this hash has good distribution (passes chi-square tests) and good avalanche effect. Also very