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v/vlib/encoding/base58/alphabet.v

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2021-08-24 06:22:46 +03:00
module base58
// alphabets is a map of common base58 alphabets
pub const alphabets = init_alphabets()
// init_alphabet instantiates the preconfigured `Alphabet`s and returns them as `map[string]Alphabet`.
// This is a temporary function. Setting const alphabets to the value returned in this function
// causes a C error right now.
fn init_alphabets() map[string]Alphabet {
return {
'btc': new_alphabet('123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz') or {
panic(@MOD + '.' + @FN + ': this should never happen')
}
'flickr': new_alphabet('123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ') or {
panic(@MOD + '.' + @FN + ': this should never happen')
}
'ripple': new_alphabet('rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz') or {
panic(@MOD + '.' + @FN + ': this should never happen')
}
}
}
// Alphabet is the series of characters that an input
// will be encoded to and a decode table.
struct Alphabet {
mut:
decode []i8 = []i8{len: 128, init: -1}
encode []byte = []byte{len: 58}
}
// str returns an Alphabet encode table byte array as a string
pub fn (alphabet Alphabet) str() string {
// i guess i had a brain fart here. Why would I actually use this code?!
// mut str := []byte{}
// for entry in alphabet.encode {
// str << entry
// }
// return str.bytestr()
return alphabet.encode.bytestr()
}
// new_alphabet instantiates an Alphabet object based on
// the provided characters
pub fn new_alphabet(str string) ?Alphabet {
if str.len != 58 {
return error(@MOD + '.' + @FN + ': string must be 58 characters in length')
}
mut ret := Alphabet{}
copy(mut ret.encode, str.bytes())
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mut distinct := 0
for i, b in ret.encode {
if ret.decode[b] == -1 {
distinct++
}
ret.decode[b] = i8(i)
}
if distinct != 58 {
return error(@MOD + '.' + @FN + ': string must not contain repeating characters')
}
return ret
}