将字符串每个字符的 CRC32 校验和值添加到数组中

Question

我正在尝试遍历一个字符串并将每个字符的CRC32校验和获取到数组中。我通过使用.each_char方法执行此操作：

def calculate_signature(data)
signature = [] of UInt32
data.each_char do |c|
signature << CRC32.checksum(c)
end
end

当我运行它时，我收到一个很长的无用错误消息。

Error in sigwaf.cr:4: instantiating 'calculate_signature(String)'
calculate_signature("yrdy")
^~~~~~~~~~~~~~~~~~~
in lib/settings.cr:17: instantiating 'String#each_char()'
data.each_char do |c|
^~~~~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/string.cr:3773: instantiating 'each_byte()'
each_byte do |byte|
^~~~~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/string.cr:3881: instantiating 'Slice(UInt8)#each()'
to_slice.each do |byte|
^~~~
in /usr/local/Cellar/crystal/0.29.0/src/indexable.cr:187: instantiating 'each_index()'
each_index do |i|
^~~~~~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/indexable.cr:187: instantiating 'each_index()'
each_index do |i|
^~~~~~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/string.cr:3881: instantiating 'Slice(UInt8)#each()'
to_slice.each do |byte|
^~~~
in /usr/local/Cellar/crystal/0.29.0/src/string.cr:3773: instantiating 'each_byte()'
each_byte do |byte|
^~~~~~~~~
in lib/settings.cr:17: instantiating 'String#each_char()'
data.each_char do |c|
^~~~~~~~~
in lib/settings.cr:18: instantiating 'CRC32:Module#checksum(Char)'
signature >> CRC32.checksum(c)
^~~~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/crc32/crc32.cr:9: instantiating 'update(Char, UInt32)'
update(data, initial)
^~~~~~
in /usr/local/Cellar/crystal/0.29.0/src/crc32/crc32.cr:13: undefined method 'to_slice' for Char
slice = data.to_slice
^~~~~~~~
Rerun with --error-trace to show a complete error trace.

如何成功将 crc32 校验和添加到数组中？

Answer 1

试试这个：

require "crc32"
def calculate_signature(data)
signature = [] of UInt32
data.chars.each do |c|
signature << CRC32.checksum(c.to_s)
end
signature
end
puts calculate_signature("string")

您收到错误是因为Char不是array of String，而是另一种array of Chars类型。Char没有 CRC32 在此行上调用的方法.to_slice并引发错误。我只是在each中为图表添加.to_s，它可以工作。您也可以将.chars替换为.split("")并获得相同的结果。

错误消息"Char的未定义方法'to_slice'"正是关于它的。