nwaku/waku/common/utils/parse_size_units.nim

52 lines
1.5 KiB
Nim

import std/strutils, stew/results, regex
proc parseMsgSize*(input: string): Result[uint64, string] =
## Parses size strings such as "1.2 KiB" or "3Kb" and returns the equivalent number of bytes
## if the parse task goes well. If not, it returns an error describing the problem.
const RegexDef = """\s*(\d+([\,\.]\d*)?)\s*([Kk]{0,1}[i]?[Bb]{1})"""
const RegexParseSize = re2(RegexDef)
var m: RegexMatch2
if input.match(RegexParseSize, m) == false:
return err("error in parseSize. regex is not matching: " & RegexDef)
var value: float
try:
value = parseFloat(input[m.captures[0]].replace(",", "."))
except ValueError:
return err(
"invalid size in parseSize: " & getCurrentExceptionMsg() & " error parsing: " &
input[m.captures[0]] & " KKK : " & $m
)
let units = input[m.captures[2]].toLowerAscii() # units is "kib", or "kb", or "b".
var multiplier: float
case units
of "kb":
multiplier = 1000
of "kib":
multiplier = 1024
of "ib":
return err("wrong units. ib or iB aren't allowed.")
else: ## bytes
multiplier = 1
value = value * multiplier
return ok(uint64(value))
proc parseCorrectMsgSize*(input: string): uint64 =
## This proc always returns an int and wraps the following proc:
##
## proc parseMsgSize*(input: string): Result[int, string] = ...
##
## in case of error, it just returns 0, and this is expected to
## be called only from a controlled and well-known inputs
let ret = parseMsgSize(input).valueOr:
return 0
return ret