bcal

bcal (Byte CALculator) is a REPL CLI utility for storage expression (e.g. "(2GiB * 2) / (2KiB >> 2)") evaluation, SI/IEC conversion, byte address calculation, base conversion and LBA/CHS calculation. It's very useful for those who deal with bits, bytes, addresses and binary prefixes frequently.

To evaluate general-purpose operations, use bcal -b or prompt key b.

bcal uses SI and IEC binary prefixes and supports 64-bit Operating Systems only.

Table of Contents

• Features
• Installation
  • Dependencies
  • From a package manager
  • From source
  • make options
  • Termux
• Usage
  • cmdline options
  • Operational notes
  • Environment variables
• Examples
• Testing
• Copyright

Features

• REPL and single execution modes
• evaluate arithmetic expressions involving storage units
• general-purpose operations
  • arithmetic: addition, subtraction, multiplication, division, modulo
  • bitwise: AND (&), OR (|), XOR (^), complement (~), lshift (<<), rshift (>>)
  • functions: exp(n), log(base, n), ln(n) [natural log], pow(n, exponent), root(radical, n), sum(n1 n2 ...)
• works with piped input or file redirection
• convert to IEC/SI standard data storage units
• REPL mode with the last valid result stored for reuse
• show the address in bytes
• show address as LBA:OFFSET
• convert CHS to LBA and vice versa
• base conversion to binary, decimal and hex
• show bit positions with bit value of a number
• custom sector size, max heads/cylinder and max sectors/track
• minimal dependencies

Installation

Dependencies

bcal is written in C and depends on standard libc and GNU Readline (or BSD Editline). However, readline can be excluded by building with O_NORL=1, which uses a native input prompt with history file support instead.

From a package manager

Install bcal from your package manager. If the version available is dated try an alternative installation method.

Packaging status (expand)

From source

If you have git installed, clone this repository. Otherwise, download the latest stable release or development version (risky).

Install to default location (/usr/local):

$ sudo make strip install

To link to libedit:

$ sudo make O_EL=1 strip install

To build without readline dependency (uses native input with history file support):

$ sudo make O_NORL=1 strip install

To uninstall, run:

$ sudo make uninstall

PREFIX is supported, in case you want to install to a different location.

make options

• O_NORL=1: build without GNU Readline (native prompt with history file support).
• O_EL=1: link against BSD Editline instead of Readline.
• O_STATIC=1: build a static binary (forces O_NORL=1).
• strip: target to strip the resulting binary after build.
• static: target to build a static binary via O_STATIC=1.

To build with musl libc, use musl-gcc as the compiler, for example:

   $ CC=musl-gcc make
   $ CC=musl-gcc make O_STATIC=1

Termux

bcal can be compiled and installed from source in the Termux environment on aarch64 Android devices. Instructions:

$ wget https://github.com/jarun/bcal/archive/master.zip
$ unzip bcal-master.zip
$ cd bcal-master/
$ pkg install make clang readline-dev
$ make strip install

Usage

cmdline options

usage: bcal [-b [expr]] [-c N] [-p N] [-f loc]
            [-s bytes] [expr] [N [unit]] [-m] [-H] [-d] [-h]

Bits, bytes and general-purpose calculator.

positional arguments:
 expr       expression in decimal/hex operands
 N [unit]   capacity in B/KiB/MiB/GiB/TiB/kB/MB/GB/TB
            https://en.wikipedia.org/wiki/Binary_prefix
            default unit is B (byte), case is ignored
            N can be decimal or '0x' prefixed hex value

optional arguments:
 -b [expr]  start in general-purpose REPL mode
            or, evaluate expression and quit
 -c N       show +ve integer N in binary, decimal, hex
 -p N       show bit position with bit value for N
 -f loc     convert CHS to LBA or LBA to CHS
            refer to the operational notes in man page
 -s bytes   sector size [default 512]
 -m         show minimal output (e.g. decimal bytes)
 -H         show integral maths results in hex
 -d         enable debug information and logs
 -h         show this help

prompt keys:
 b          toggle general-purpose mode
 c N        show +ve integer N in binary, decimal, hex
 p N        show bit position with bit value for N
 r          show result from last operation
 s          show sizes of storage types
 ?          show prompt help
 q/double ↵ quit program
 prompt: bytes> for storage mode, maths> for general-purpose mode

Operational notes

• REPL mode: bcal enters the REPL mode if no arguments are provided. Storage unit conversion, base conversion and expression evaluation are supported in this mode. The last valid result is stored in the variable r.
• Expression: Expression passed as argument in single execution mode must be quoted. Inner spaces are ignored. Operators supported in storage expressions: +, -, *, /, %.
• N [unit]: N can be a decimal or '0x' prefixed hex value. unit can be B/KiB/MiB/GiB/TiB/kB/MB/GB/TB. Default is Byte. As all of these tokens are unique, unit is case-insensitive. Note that bcal doesn't support bit as a unit.
• Numeric representation: Decimal and hex are recognized in expressions and unit conversions. Binary is also recognized in other operations.
• Syntax: Prefix hex inputs with 0x, binary inputs with 0b.
• Precision: 128 bits if __uint128_t is available or 64 bits for numeric conversions. Floating point operations use long double. Negative values in storage expressions are unsupported. Only 64-bit operating systems are supported.
• Fractional bytes do not exist because they can't be addressed. bcal shows the floor value of non-integer bytes.
• CHS and LBA syntax:
  • LBA: lLBA-MAX_HEAD-MAX_SECTOR [NOTE: LBA starts with l (case ignored)]
  • CHS: cC-H-S-MAX_HEAD-MAX_SECTOR [NOTE: CHS starts with c (case ignored)]
  • Format conversion arguments must be hyphen separated.
  • Any unspecified value, including the one preceding the first - to the one following the last -, is considered 0 (zero).
  • Examples:
    • c-50--0x12- -> C = 0, H = 50, S = 0, MH = 0x12, MS = 0
    • l50-0x12 -> LBA = 50, MH = 0x12, MS = 0
• Default values:
  • sector size: 0x200 (512)
  • max heads per cylinder: 0x10 (16)
  • max sectors per track: 0x3f (63)
• REPL mode: r is synced and can be used in expressions. The built-in evaluator uses long double arithmetic.
• History file: Stored at $XDG_CONFIG_HOME/bcal/history, or $HOME/.config/bcal/history if XDG_CONFIG_HOME is unset.

Environment variables

• BCAL_BIT_ANSI_COLOR_CODE: ANSI escape code to colorize bit value 1 in -p output. Set to empty to disable coloring. Examples:

  export BCAL_BIT_ANSI_COLOR_CODE=$'\033[1;92m'         // ANSI 8-bit color code
  export BCAL_BIT_ANSI_COLOR_CODE=$'\u001b[1;38;5;51m'  // ANSI 256-bit color code
  export BCAL_BIT_ANSI_COLOR_CODE=''                    // Disable coloring
  

Examples

1. Evaluate arithmetic expression of storage units.

   $ bcal "(5kb+2mb)/3"
   $ bcal "5 tb / 12"
   $ bcal "2.5mb*3"
   $ bcal "(2giB * 2) / (2kib >> 2)"
   

2. Convert storage capacity to other units and get address, LBA.

   $ bcal 20140115 b
   $ bcal 0x1335053 B
   $ bcal 0xaabbcc kb
   $ bcal 0xdef Gib
   

   Note that the units are case-insensitive.

3. Convert storage capacity, set sector size to 4096 to calculate LBA.

   $ bcal 0xaabbcc kb -s 4096
   

4. Convert LBA to CHS.

   $ bcal -f l500
   $ bcal -f l0x600-18-0x7e
   $ bcal -f l0x300-0x12-0x7e
   

5. Convert CHS to LBA.

   $ bcal -f c10-10-10
   $ bcal -f c0x10-0x10-0x10
   $ bcal -f c0x10-10-2-0x12
   $ bcal -f c-10-2-0x12
   $ bcal -f c0x10-10--0x12
   

6. Show binary, decimal and hex representations of a number.

   $ bcal -c 20140115
   $ bcal -c 0b1001100110101000001010011
   $ bcal -c 0x1335053
   bytes> c 20140115  // REPL mode
   maths> c 20140115  // REPL mode
   

7. Perform bitwise operations.

   $ bcal -b '0xFF & 0x0F'
   $ bcal -b '0x0F | 0xF0'
   $ bcal -b '0xFF ^ 0xF0'
   $ bcal -b '0xF0'
   $ bcal -b '0x01 << 3'
   $ bcal -b '0x10 >> 2'
   $ bcal -b '(0xFF & 0x0F) | (0x0F << 4)'
   

8. Use as a general-purpose calculator.

   $ bcal -b '3.5 * 2.1 + 5.7' // Single execution mode
   $ bcal -b // Start in geenral-purpose REPL mode
   $ bcal
   bcal> b   // Switch to general-purpose mode
   expr> 3.5 * 2.1 + 5.7
   

9. Pipe input.

   $ printf '15 kib + 15 gib \n r / 5' | bcal -m
   $ printf '15 + 15 + 2' | bcal -bm
   

10. Redirect from file.

    $ cat expr
    15 gib + 15 kib
    r / 5
    $ bcal -m < expr
    

11. Use mathematical functions.

    $ bcal -b 'root(2, 17.3)'  // square root of 17.3
    $ bcal -b 'exp(5.2)'
    $ bcal -b 'pow(2, 8)'
    

    $ bcal -b 'sum(1 2 3 4)' $ bcal -b 'pow(10, 3) + root(2, 9)'

12. Show bit positions with values.

Testing

Due to the nature of the project, it's extremely important to test existing functionality before raising any PR. bcal has several test cases written in test.py. To execute the test cases locally, install pytest and run:

$ make
$ python3 -m pytest test.py

Copyright

Copyright © 2016 Arun Prakash Jana