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div class="Breadcrumb-module__container__Vxvev Breadcrumb-module__md__Wb1Gs">
/
format.rs
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662 lines (608 loc) · 20.8 KB
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use num_bigint::{BigInt, Sign};
use num_traits::Signed;
use std::cmp;
use std::str::FromStr;
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum FormatAlign {
Left,
Right,
AfterSign,
Center,
}
impl FormatAlign {
fn from_char(c: char) -> Option<FormatAlign> {
match c {
'<' => Some(FormatAlign::Left),
'>' => Some(FormatAlign::Right),
'=' => Some(FormatAlign::AfterSign),
'^' => Some(FormatAlign::Center),
_ => None,
}
}
}
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum FormatSign {
Plus,
Minus,
MinusOrSpace,
}
#[derive(Debug, PartialEq)]
pub enum FormatGrouping {
Comma,
Underscore,
}
#[derive(Debug, PartialEq)]
pub enum FormatType {
String,
Binary,
Character,
Decimal,
Octal,
HexLower,
HexUpper,
Number,
ExponentLower,
ExponentUpper,
GeneralFormatLower,
GeneralFormatUpper,
FixedPointLower,
FixedPointUpper,
}
#[derive(Debug, PartialEq)]
pub struct FormatSpec {
fill: Option<char>,
align: Option<FormatAlign>,
sign: Option<FormatSign>,
alternate_form: bool,
width: Option<usize>,
grouping_option: Option<FormatGrouping>,
precision: Option<usize>,
format_type: Option<FormatType>,
}
fn get_num_digits(text: &str) -> usize {
for (index, character) in text.char_indices() {
if !character.is_digit(10) {
return index;
}
}
text.len()
}
fn parse_align(text: &str) -> (Option<FormatAlign>, &str) {
let mut chars = text.chars();
let maybe_align = chars.next().and_then(FormatAlign::from_char);
if maybe_align.is_some() {
(maybe_align, &chars.as_str())
} else {
(None, text)
}
}
fn parse_fill_and_align(text: &str) -> (Option<char>, Option<FormatAlign>, &str) {
let char_indices: Vec<(usize, char)> = text.char_indices().take(3).collect();
if char_indices.is_empty() {
(None, None, text)
} else if char_indices.len() == 1 {
let (maybe_align, remaining) = parse_align(text);
(None, maybe_align, remaining)
} else {
let (maybe_align, remaining) = parse_align(&text[char_indices[1].0..]);
if maybe_align.is_some() {
(Some(char_indices[0].1), maybe_align, remaining)
} else {
let (only_align, only_align_remaining) = parse_align(text);
(None, only_align, only_align_remaining)
}
}
}
fn parse_number(text: &str) -> (Option<usize>, &str) {
let num_digits: usize = get_num_digits(text);
if num_digits == 0 {
return (None, text);
}
// This should never fail
(
Some(text[..num_digits].parse::<usize>().unwrap()),
&text[num_digits..],
)
}
fn parse_sign(text: &str) -> (Option<FormatSign>, &str) {
let mut chars = text.chars();
match chars.next() {
Some('-') => (Some(FormatSign::Minus), chars.as_str()),
Some('+') => (Some(FormatSign::Plus), chars.as_str()),
Some(' ') => (Some(FormatSign::MinusOrSpace), chars.as_str()),
_ => (None, text),
}
}
fn parse_alternate_form(text: &str) -> (bool, &str) {
let mut chars = text.chars();
match chars.next() {
Some('#') => (true, chars.as_str()),
_ => (false, text),
}
}
fn parse_zero(text: &str) -> &str {
let mut chars = text.chars();
match chars.next() {
Some('0') => chars.as_str(),
_ => text,
}
}
fn parse_precision(text: &str) -> (Option<usize>, &str) {
let mut chars = text.chars();
match chars.next() {
Some('.') => {
let (size, remaining) = parse_number(&chars.as_str());
if size.is_some() {
(size, remaining)
} else {
(None, text)
}
}
_ => (None, text),
}
}
fn parse_grouping_option(text: &str) -> (Option<FormatGrouping>, &str) {
let mut chars = text.chars();
match chars.next() {
Some('_') => (Some(FormatGrouping::Underscore), chars.as_str()),
Some(',') => (Some(FormatGrouping::Comma), chars.as_str()),
_ => (None, text),
}
}
fn parse_format_type(text: &str) -> (Option<FormatType>, &str) {
let mut chars = text.chars();
match chars.next() {
Some('b') => (Some(FormatType::Binary), chars.as_str()),
Some('c') => (Some(FormatType::Character), chars.as_str()),
Some('d') => (Some(FormatType::Decimal), chars.as_str()),
Some('o') => (Some(FormatType::Octal), chars.as_str()),
Some('x') => (Some(FormatType::HexLower), chars.as_str()),
Some('X') => (Some(FormatType::HexUpper), chars.as_str()),
Some('e') => (Some(FormatType::ExponentLower), chars.as_str()),
Some('E') => (Some(FormatType::ExponentUpper), chars.as_str()),
Some('f') => (Some(FormatType::FixedPointLower), chars.as_str()),
Some('F') => (Some(FormatType::FixedPointUpper), chars.as_str()),
Some('g') => (Some(FormatType::GeneralFormatLower), chars.as_str()),
Some('G') => (Some(FormatType::GeneralFormatUpper), chars.as_str()),
Some('n') => (Some(FormatType::Number), chars.as_str()),
_ => (None, text),
}
}
fn parse_format_spec(text: &str) -> FormatSpec {
let (fill, align, after_align) = parse_fill_and_align(text);
let (sign, after_sign) = parse_sign(after_align);
let (alternate_form, after_alternate_form) = parse_alternate_form(after_sign);
let after_zero = parse_zero(after_alternate_form);
let (width, after_width) = parse_number(after_zero);
let (grouping_option, after_grouping_option) = parse_grouping_option(after_width);
let (precision, after_precision) = parse_precision(after_grouping_option);
let (format_type, _) = parse_format_type(after_precision);
FormatSpec {
fill,
align,
sign,
alternate_form,
width,
grouping_option,
precision,
format_type,
}
}
impl FormatSpec {
pub fn parse(text: &str) -> FormatSpec {
parse_format_spec(text)
}
fn compute_fill_string(fill_char: char, fill_chars_needed: i32) -> String {
(0..fill_chars_needed)
.map(|_| fill_char)
.collect::<String>()
}
fn add_magnitude_separators_for_char(
magnitude_string: String,
interval: usize,
separator: char,
) -> String {
let mut result = String::new();
let mut remaining: usize = magnitude_string.len() % interval;
if remaining == 0 {
remaining = interval;
}
for c in magnitude_string.chars() {
result.push(c);
if remaining == 0 {
result.push(separator);
remaining = interval;
}
}
result
}
fn get_separator_interval(&self) -> usize {
match self.format_type {
Some(FormatType::Binary) => 4,
Some(FormatType::Decimal) => 3,
Some(FormatType::Octal) => 4,
Some(FormatType::HexLower) => 4,
Some(FormatType::HexUpper) => 4,
Some(FormatType::Number) => 3,
None => 3,
_ => panic!("Separators only valid for numbers!"),
}
}
fn add_magnitude_separators(&self, magnitude_string: String) -> String {
match self.grouping_option {
Some(FormatGrouping::Comma) => FormatSpec::add_magnitude_separators_for_char(
magnitude_string,
self.get_separator_interval(),
',',
),
Some(FormatGrouping::Underscore) => FormatSpec::add_magnitude_separators_for_char(
magnitude_string,
self.get_separator_interval(),
'_',
),
None => magnitude_string,
}
}
pub fn format_int(&self, num: &BigInt) -> Result<String, &'static str> {
let fill_char = self.fill.unwrap_or(' ');
let magnitude = num.abs();
let prefix = if self.alternate_form {
match self.format_type {
Some(FormatType::Binary) => "0b",
Some(FormatType::Octal) => "0o",
Some(FormatType::HexLower) => "0x",
Some(FormatType::HexUpper) => "0x",
_ => "",
}
} else {
""
};
let raw_magnitude_string_result: Result<String, &'static str> = match self.format_type {
Some(FormatType::Binary) => Ok(magnitude.to_str_radix(2)),
Some(FormatType::Decimal) => Ok(magnitude.to_str_radix(10)),
Some(FormatType::Octal) => Ok(magnitude.to_str_radix(8)),
Some(FormatType::HexLower) => Ok(magnitude.to_str_radix(16)),
Some(FormatType::HexUpper) => {
let mut result = magnitude.to_str_radix(16);
result.make_ascii_uppercase();
Ok(result)
}
Some(FormatType::Number) => Ok(magnitude.to_str_radix(10)),
Some(FormatType::String) => Err("Unknown format code 's' for object of type 'int'"),
Some(FormatType::Character) => Err("Unknown format code 'c' for object of type 'int'"),
Some(FormatType::GeneralFormatUpper) => {
Err("Unknown format code 'G' for object of type 'int'")
}
Some(FormatType::GeneralFormatLower) => {
Err("Unknown format code 'g' for object of type 'int'")
}
Some(FormatType::ExponentUpper) => {
Err("Unknown format code 'E' for object of type 'int'")
}
Some(FormatType::ExponentLower) => {
Err("Unknown format code 'e' for object of type 'int'")
}
Some(FormatType::FixedPointUpper) => {
Err("Unknown format code 'F' for object of type 'int'")
}
Some(FormatType::FixedPointLower) => {
Err("Unknown format code 'f' for object of type 'int'")
}
None => Ok(magnitude.to_str_radix(10)),
};
if raw_magnitude_string_result.is_err() {
return raw_magnitude_string_result;
}
let magnitude_string = format!(
"{}{}",
prefix,
self.add_magnitude_separators(raw_magnitude_string_result.unwrap())
);
let align = self.align.unwrap_or(FormatAlign::Right);
// Use the byte length as the string length since we're in ascii
let num_chars = magnitude_string.len();
let format_sign = self.sign.unwrap_or(FormatSign::Minus);
let sign_str = match num.sign() {
Sign::Minus => "-",
_ => match format_sign {
FormatSign::Plus => "+",
FormatSign::Minus => "",
FormatSign::MinusOrSpace => " ",
},
};
let fill_chars_needed: i32 = self.width.map_or(0, |w| {
cmp::max(0, (w as i32) - (num_chars as i32) - (sign_str.len() as i32))
});
Ok(match align {
FormatAlign::Left => format!(
"{}{}{}",
sign_str,
magnitude_string,
FormatSpec::compute_fill_string(fill_char, fill_chars_needed)
),
FormatAlign::Right => format!(
"{}{}{}",
FormatSpec::compute_fill_string(fill_char, fill_chars_needed),
sign_str,
magnitude_string
),
FormatAlign::AfterSign => format!(
"{}{}{}",
sign_str,
FormatSpec::compute_fill_string(fill_char, fill_chars_needed),
magnitude_string
),
FormatAlign::Center => {
let left_fill_chars_needed = fill_chars_needed / 2;
let right_fill_chars_needed = fill_chars_needed - left_fill_chars_needed;
let left_fill_string =
FormatSpec::compute_fill_string(fill_char, left_fill_chars_needed);
let right_fill_string =
FormatSpec::compute_fill_string(fill_char, right_fill_chars_needed);
format!(
"{}{}{}{}",
left_fill_string, sign_str, magnitude_string, right_fill_string
)
}
})
}
}
#[derive(Debug, PartialEq)]
pub enum FormatParseError {
UnmatchedBracket,
MissingStartBracket,
UnescapedStartBracketInLiteral,
}
impl FromStr for FormatSpec {
type Err = &'static str;
fn from_str(s: &str) -> Result<Self, Self::Err> {
Ok(FormatSpec::parse(s))
}
}
#[derive(Debug, PartialEq)]
pub enum FormatPart {
AutoSpec(String),
IndexSpec(usize, String),
KeywordSpec(String, String),
Literal(String),
}
impl FormatPart {
pub fn is_auto(&self) -> bool {
match self {
FormatPart::AutoSpec(_) => true,
_ => false,
}
}
pub fn is_index(&self) -> bool {
match self {
FormatPart::IndexSpec(_, _) => true,
_ => false,
}
}
}
#[derive(Debug, PartialEq)]
pub struct FormatString {
pub format_parts: Vec<FormatPart>,
}
impl FormatString {
fn parse_literal_single(text: &str) -> Result<(char, &str), FormatParseError> {
let mut chars = text.chars();
// This should never be called with an empty str
let first_char = chars.next().unwrap();
if first_char == '{' || first_char == '}' {
let maybe_next_char = chars.next();
// if we see a bracket, it has to be escaped by doubling up to be in a literal
if maybe_next_char.is_some() && maybe_next_char.unwrap() != first_char {
return Err(FormatParseError::UnescapedStartBracketInLiteral);
} else {
return Ok((first_char, chars.as_str()));
}
}
Ok((first_char, chars.as_str()))
}
fn parse_literal(text: &str) -> Result<(FormatPart, &str), FormatParseError> {
let mut cur_text = text;
let mut result_string = String::new();
while !cur_text.is_empty() {
match FormatString::parse_literal_single(cur_text) {
Ok((next_char, remaining)) => {
result_string.push(next_char);
cur_text = remaining;
}
Err(err) => {
if !result_string.is_empty() {
return Ok((FormatPart::Literal(result_string.to_string()), cur_text));
} else {
return Err(err);
}
}
}
}
Ok((FormatPart::Literal(result_string), ""))
}
fn parse_part_in_brackets(text: &str) -> Result<FormatPart, FormatParseError> {
let parts: Vec<&str> = text.splitn(2, ':').collect();
// before the comma is a keyword or arg index, after the comma is maybe a spec.
let arg_part = parts[0];
let format_spec = if parts.len() > 1 {
parts[1].to_string()
} else {
String::new()
};
if arg_part.is_empty() {
return Ok(FormatPart::AutoSpec(format_spec));
}
if let Ok(index) = arg_part.parse::<usize>() {
Ok(FormatPart::IndexSpec(index, format_spec))
} else {
Ok(FormatPart::KeywordSpec(arg_part.to_string(), format_spec))
}
}
fn parse_spec(text: &str) -> Result<(FormatPart, &str), FormatParseError> {
let mut chars = text.chars();
if chars.next() != Some('{') {
return Err(FormatParseError::MissingStartBracket);
}
// Get remaining characters after opening bracket.
let cur_text = chars.as_str();
// Find the matching bracket and parse the text within for a spec
match cur_text.find('}') {
Some(position) => {
let (left, right) = cur_text.split_at(position);
let format_part = FormatString::parse_part_in_brackets(left)?;
Ok((format_part, &right[1..]))
}
None => Err(FormatParseError::UnmatchedBracket),
}
}
}
impl FromStr for FormatString {
type Err = FormatParseError;
fn from_str(text: &str) -> Result<Self, Self::Err> {
let mut cur_text: &str = text;
let mut parts: Vec<FormatPart> = Vec::new();
while !cur_text.is_empty() {
// Try to parse both literals and bracketed format parts util we
// run out of text
cur_text = FormatString::parse_literal(cur_text)
.or_else(|_| FormatString::parse_spec(cur_text))
.map(|(part, new_text)| {
parts.push(part);
new_text
})?;
}
Ok(FormatString {
format_parts: parts,
})
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_fill_and_align() {
assert_eq!(
parse_fill_and_align(" <"),
(Some(' '), Some(FormatAlign::Left), "")
);
assert_eq!(
parse_fill_and_align(" <22"),
(Some(' '), Some(FormatAlign::Left), "22")
);
assert_eq!(
parse_fill_and_align("<22"),
(None, Some(FormatAlign::Left), "22")
);
assert_eq!(
parse_fill_and_align(" ^^"),
(Some(' '), Some(FormatAlign::Center), "^")
);
assert_eq!(
parse_fill_and_align("==="),
(Some('='), Some(FormatAlign::AfterSign), "=")
);
}
#[test]
fn test_width_only() {
let expected = FormatSpec {
fill: None,
align: None,
sign: None,
alternate_form: false,
width: Some(33),
grouping_option: None,
precision: None,
format_type: None,
};
assert_eq!(parse_format_spec("33"), expected);
}
#[test]
fn test_fill_and_width() {
let expected = FormatSpec {
fill: Some('<'),
align: Some(FormatAlign::Right),
sign: None,
alternate_form: false,
width: Some(33),
grouping_option: None,
precision: None,
format_type: None,
};
assert_eq!(parse_format_spec("<>33"), expected);
}
#[test]
fn test_all() {
let expected = FormatSpec {
fill: Some('<'),
align: Some(FormatAlign::Right),
sign: Some(FormatSign::Minus),
alternate_form: true,
width: Some(23),
grouping_option: Some(FormatGrouping::Comma),
precision: Some(11),
format_type: Some(FormatType::Binary),
};
assert_eq!(parse_format_spec("<>-#23,.11b"), expected);
}
#[test]
fn test_format_int() {
assert_eq!(
parse_format_spec("d").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("16".to_string())
);
assert_eq!(
parse_format_spec("x").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("10".to_string())
);
assert_eq!(
parse_format_spec("b").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("10000".to_string())
);
assert_eq!(
parse_format_spec("o").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("20".to_string())
);
assert_eq!(
parse_format_spec("+d").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("+16".to_string())
);
assert_eq!(
parse_format_spec("^ 5d").format_int(&BigInt::from_bytes_be(Sign::Minus, b"\x10")),
Ok(" -16 ".to_string())
);
assert_eq!(
parse_format_spec("0>+#10x").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("00000+0x10".to_string())
);
}
#[test]
fn test_format_parse() {
let expected = Ok(FormatString {
format_parts: vec![
FormatPart::Literal("abcd".to_string()),
FormatPart::IndexSpec(1, String::new()),
FormatPart::Literal(":".to_string()),
FormatPart::KeywordSpec("key".to_string(), String::new()),
],
});
assert_eq!(FormatString::from_str("abcd{1}:{key}"), expected);
}
#[test]
fn test_format_parse_fail() {
assert_eq!(
FormatString::from_str("{s"),
Err(FormatParseError::UnmatchedBracket)
);
}
#[test]
fn test_format_parse_escape() {
let expected = Ok(FormatString {
format_parts: vec![
FormatPart::Literal("{".to_string()),
FormatPart::KeywordSpec("key".to_string(), String::new()),
FormatPart::Literal("}ddfe".to_string()),
],
});
assert_eq!(FormatString::from_str("{{{key}}}ddfe"), expected);
}
}