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Binsearch

Fast binary search for columnar data formats.

Master Build Status Master Coverage Status

Description

The functions provided here allows to search unsigned integers in a binary file made of adjacent constant-length binary blocks sorted in ascending order.

For example, the first 4 bytes of each 8-bytes blocks below represent a uint32 in big-endian. The integers are sorted in ascending order.

2f 81 f5 77 1a cc 7b 43
2f 81 f5 78 76 5f 63 b8
2f 81 f5 79 ca a9 a6 52

This binary representation can be used to encode sortable key-value data, even with nested keys.

The xxd command-line application can be used to convert a binary file to hexdump and reverse. For example:

xxd -p -c8 binaryfile.bin > hexfile.txt
xxd -r -p hexfile.txt > binaryfile.bin

This library also provide functions to read columnar data in Little-Endian format.

The mmap_binfile function is able to extract some basic data from files in Apache Arrow, Feather or custom BINSRC format.

Getting Started

The reference code of this application is written in C language and includes wrappers for GO and Python.

A wrapper Makefile is available to allows building the project in a Linux-compatible system with simple commands.
All the artifacts and reports produced using this Makefile are stored in the target folder.

To see all available options:

make help

use the command make all to build and test all the implementations.

NOTE

  • the "be" or "BE" functions refer to source files sorted in Big-Endian.
  • the "le" or "LE" functions refer to source files sorted in Little-Endian.

BINSRC Format:

  • 8 BYTE : BINSRC1\0 magic number
  • 1 BYTE : Number of columns.
  • One byte for each column type (i.e. 1 for uint8, 2 for uint16, 4 for uint32, 8 for uint64).
  • (PADDING TO ALIGN THE DATA TO 8 BYTE)
  • 8 BYTE : number of rows
  • cols * 8 BYTE : offset to the start of each column
  • (DATA BODY AS IN APACHE ARROW)

Example

42494e5352433100    : BINSRC1 magic number
02                  : 2 columns
04                  : first column is uint32_t (4 bytes)
08                  : second column is uint64_t (8 bytes)
0000000000          : padding to 8 byte
0b00000000000000    : 11 rows per columns
2800000000000000    : byte offset to the start of the first column
5800000000000000    : byte offset to the start of the second column
01000000            : first column - first row
07000000            : ...
0b000000            : 
61000000            : 
65000000            : 
e5030000            : 
f1030000            : 
f5260000            : 
a3860100            : 
19990100            : 
19990100            : 
00000000            : 
00803380257a0208    : second column - first row
18399e43fea10048    : ...
16eb5575fea10048    : 
00003a0074020180    : 
008013008d020180    : 
00007a0099020180    : 
00003a00622b01a0    : 
00807080622b01a0    : 
926625e3652b01a0    : 
039843d5672b01a0    : 
039843d5672b01a0    :