nim-codex/codex/utils.nim

94 lines
3.3 KiB
Nim

## Nim-Codex
## Copyright (c) 2023 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
##
import std/parseutils
import std/options
import pkg/chronos
import ./utils/asyncheapqueue
import ./utils/fileutils
import ./utils/asynciter
export asyncheapqueue, fileutils, asynciter
func divUp*[T: SomeInteger](a, b : T): T =
## Division with result rounded up (rather than truncated as in 'div')
assert(b != T(0))
if a==T(0): T(0) else: ((a - T(1)) div b) + T(1)
func roundUp*[T](a, b : T): T =
## Round up 'a' to the next value divisible by 'b'
divUp(a,b) * b
proc orElse*[A](a, b: Option[A]): Option[A] =
if (a.isSome()):
a
else:
b
when not declared(parseDuration): # Odd code formatting to minimize diff v. mainLine
const Whitespace = {' ', '\t', '\v', '\r', '\l', '\f'}
func toLowerAscii(c: char): char =
if c in {'A'..'Z'}: char(uint8(c) xor 0b0010_0000'u8) else: c
func parseDuration*(s: string, size: var Duration): int =
## Parse a size qualified by simple time into `Duration`.
##
runnableExamples:
var res: Duration # caller must still know if 'b' refers to bytes|bits
doAssert parseDuration("10H", res) == 3
doAssert res == initDuration(hours=10)
doAssert parseDuration("64m", res) == 6
doAssert res == initDuration(minutes=64)
doAssert parseDuration("7m/block", res) == 2 # '/' stops parse
doAssert res == initDuration(minutes=7) # 1 shl 30, forced binary metric
doAssert parseDuration("3d", res) == 2 # '/' stops parse
doAssert res == initDuration(days=3) # 1 shl 30, forced binary metric
const prefix = "s" & "mhdw" # byte|bit & lowCase metric-ish prefixes
const timeScale = [1.0, 60.0, 3600.0, 86_400.0, 604_800.0]
var number: float
var scale = 1.0
result = parseFloat(s, number)
if number < 0: # While parseFloat accepts negatives ..
result = 0 #.. we do not since sizes cannot be < 0
else:
let start = result # Save spot to maybe unwind white to EOS
while result < s.len and s[result] in Whitespace:
inc result
if result < s.len: # Illegal starting char => unity
if (let si = prefix.find(s[result].toLowerAscii); si >= 0):
inc result # Now parse the scale
scale = timeScale[si]
else: # Unwind result advancement when there..
result = start #..is no unit to the end of `s`.
var sizeF = number * scale + 0.5 # Saturate to int64.high when too big
size = seconds(int(sizeF))
when isMainModule:
import unittest2
suite "time parse":
test "parseDuration":
var res: Duration # caller must still know if 'b' refers to bytes|bits
check parseDuration("10Hr", res) == 3
check res == hours(10)
check parseDuration("64min", res) == 3
check res == minutes(64)
check parseDuration("7m/block", res) == 2 # '/' stops parse
check res == minutes(7) # 1 shl 30, forced binary metric
check parseDuration("3d", res) == 2 # '/' stops parse
check res == days(3) # 1 shl 30, forced binary metric