Tag - crc32c

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2021-05-08

Enhanced Faster ZIP Support in mORMot 2

The .zip format is from last century, back to the early DOS days, but can still be found everywhere. It is even hidden when you run a .docx document, a .jar application, or any Android app!
It is therefore (ab)used not only as archive format, but as application file format / container - even if in this respect using SQLite3 may have much more sense.

We recently enhanced our mormot.core.zip.pas unit:

  • to support Zip64,
  • with enhanced .zip read/write,
  • to have a huge performance boost during its process,
  • and to integrate better with signed executables.

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2021-02-12

New AesNiHash for mORMot 2

I have just committed some new AesNiHash32 AesNiHash64 AesNiHash128 Hashers for mORMot 2. They are using AES-NI and SSE4.1 opcodes on x86_64 and i386. This implementation is faster than the fastest SSE4.1 crc32c and with a much higher usability (less collisions). Logic was extracted from the Go  […]

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2018-02-07

Status of mORMot ORM SOA MVC with FPC

In the last weeks/months, we worked a lot with FPC.
Delphi is still our main IDE, due to its better debugging experience under Windows, but we target to have premium support of FPC, on all platforms, especially Linux.

The new Delphi Linux compiler is out of scope, since it is heavily priced, its performance is not so good, and ARC broke memory management so would need a deep review/rewrite of our source code, which we can't afford - since we have FPC which is, from our opinion,  a much better compiler for Linux.
Of course, you can create clients for Delphi Linux and FMX, as usual, using the cross-platform client parts of mORMot. But for server side, this compiler is not supported, and will probably never be.

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2014-05-25

New crc32c() function using optimized asm and SSE 4.2 instruction

Cyclic Redundancy Check (CRC) codes are widely used for integrity checking of data in fields such as storage and networking.
There is an ever-increasing need for very high-speed CRC computations on processors for end-to-end integrity checks.

We just introduced to mORMot's core unit (SynCommons.pas) a fast and efficient crc32c() function.

It will use either:

  • Optimized x86 asm code, with unrolled loops;
  • SSE 4.2 hardware crc32 instruction, if available.

Resulting speed is very good.
This is for sure the fastest CRC function available in Delphi.
Note that there is a version dedicated to each Win32 and Win64 platform - both performs at the same speed!

In fact, most popular file formats and protocols (Ethernet, MPEG-2, ZIP, RAR, 7-Zip, GZip, and PNG) use the polynomial $04C11DB7, while Intel's hardware implementation is based on another polynomial, $1EDC6F41 (used in iSCSI and Btrfs).
So you would not use this new crc32c() function to replace the zlib's crc32() function, but as a convenient very fast hashing function at application level.
For instance, our TDynArray wrapper will use it for fast items hashing.

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