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retired
A standard library for the Gleam programming language
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src/gleam/bit_string.gleam
//// Working with raw bit string data.
//// The BitString type should be used instead of a String type when not utf8
//// encoded.
pub type BitString =
BitString
/// Converts a UTF-8 String type into a raw BitString type.
///
pub external fn from_string(String) -> BitString =
"gleam_stdlib" "identity"
/// Returns an integer which is the number of bytes in the bit string.
///
pub external fn byte_size(BitString) -> Int =
"erlang" "byte_size"
/// Creates a new bit string by joining two binaries.
///
/// ## Examples
///
/// > append(to: from_string("butter"), suffix: from_string("fly"))
/// from_string("butterfly")
///
pub external fn append(first: BitString, second: BitString) -> BitString =
"gleam_stdlib" "bit_string_append"
/// Extracts part of a bit string.
///
/// BitString part will start at given position and continue up to specified
/// length.
/// A negative length can be used to extract bytes at the end of a bit string.
///
pub external fn part(
string: BitString,
position: Int,
length: Int,
) -> Result(BitString, Nil) =
"gleam_stdlib" "bit_string_part_"
/// Converts an integer to unsigned 32 bits.
///
/// Returns an error if integer is less than zero or equal to or larger than
/// 2^32.
///
pub external fn int_to_u32(Int) -> Result(BitString, Nil) =
"gleam_stdlib" "bit_string_int_to_u32"
/// Converts unsigned 32 bits to an integer.
///
/// Returns an error if the bit string is not 32 bits in length.
///
pub external fn int_from_u32(BitString) -> Result(Int, Nil) =
"gleam_stdlib" "bit_string_int_from_u32"
/// Tests to see whether a bit string is valid UTF-8.
///
pub fn is_utf8(bits: BitString) -> Bool {
case bits {
<<>> -> True
<<_:utf8, rest:binary>> -> is_utf8(rest)
_ -> False
}
}
external fn unsafe_to_string(BitString) -> String =
"gleam_stdlib" "identity"
/// Converts a bit string to a string.
///
/// Returns an error if the bit string is invalid UTF-8 data.
///
pub fn to_string(bits: BitString) -> Result(String, Nil) {
case is_utf8(bits) {
True -> Ok(unsafe_to_string(bits))
False -> Error(Nil)
}
}