将字符串的每个字符的 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 校验和放入一个数组中。我正在使用 .each_char 方法这样做：

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

当我运行执行此操作时，我收到了一条非常长且无用的错误消息。

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.

如何才能成功地将 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")

你收到错误是因为 Char 不是 array of String，它是另一种类型 array of Chars。 Char 没有 CRC32 在此 row 上调用的方法 .to_slice，它会引发错误。我只是在 each 中为 Chart 添加 .to_s 并且它有效。您也可以将 .chars 替换为 .split("") 并得到相同的结果。

错误消息 «undefined method 'to_slice' for Char» 正是关于它。

将字符串的每个字符的 CRC32 校验和值添加到数组中

Add the CRC32 checksum value of each character of a string, into an array

crystal-lang