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use std::{
borrow::Cow,
io::{BufRead, BufReader, Read},
str::{from_utf8, FromStr},
};
use crate::{
error::{Error, ParseError},
result::Result,
utils::read_line,
};
use bitflags::bitflags;
const MAGIC_NUMBER: &'static [u8] = b"flf2a";
bitflags! {
pub struct Layout: u32 {
const HORIZONTAL_EQUAL = 1;
const HORIZONTAL_LOWLINE = 2;
const HORIZONTAL_HIERARCHY = 4;
const HORIZONTAL_PAIR = 8;
const HORIZONTAL_BIGX = 16;
const HORIZONTAL_HARDBLANK = 32;
const HORIZONTAL_KERNING = 64;
const HORIZONTAL_SMUSH = 128;
const VERTICAL_EQUAL = 256;
const VERTICAL_LOWLINE = 512;
const VERTICAL_HIERARCHY = 1024;
const VERTICAL_PAIR = 2048;
const VERTICAL_BIGX = 4096;
const VERTICAL_KERNING = 8192;
const VERTICAL_SMUSH = 16392;
}
}
impl FromStr for Layout {
type Err = Error;
fn from_str(raw: &str) -> std::result::Result<Self, <Self as FromStr>::Err> {
let raw: u32 = raw
.parse()
.ok()
.ok_or::<Error>(ParseError::InvalidHeader.into())?;
Layout::from_bits(raw).ok_or(ParseError::InvalidHeader.into())
}
}
#[derive(Debug)]
pub struct Header {
hard_blank_char: Vec<u8>,
height: usize,
baseline: usize,
max_length: usize,
layout: Layout,
comment: String,
print_direction: PrintDirection,
codetag_count: Option<u32>,
}
impl Header {
pub(crate) fn parse<R: Read>(bread: &mut BufReader<R>) -> Result<Header> {
parse_header(bread)
}
pub fn hard_blank_char<'a>(&'a self) -> &'a [u8] {
&self.hard_blank_char[..]
}
pub fn height(&self) -> usize {
self.height
}
pub fn baseline(&self) -> usize {
self.baseline
}
pub fn max_length(&self) -> usize {
self.max_length
}
pub fn layout(&self) -> Layout {
self.layout
}
pub fn comment<'a>(&'a self) -> Cow<'a, str> {
Cow::Borrowed(&self.comment)
}
pub fn print_direction(&self) -> PrintDirection {
self.print_direction
}
pub fn codetag_count(&self) -> Option<u32> {
self.codetag_count
}
}
#[derive(Debug, Copy, Clone)]
pub enum PrintDirection {
LeftToRight,
RightToLeft,
}
impl FromStr for PrintDirection {
type Err = ParseError;
fn from_str(text: &str) -> std::result::Result<Self, <Self as FromStr>::Err> {
match text.parse::<u8>() {
Ok(n) => match n {
0 => Ok(Self::LeftToRight),
1 => Ok(Self::RightToLeft),
_ => Err(ParseError::InvalidHeader),
},
Err(_) => Err(ParseError::InvalidHeader),
}
}
}
fn read_string_lines<R: Read>(bread: &mut BufReader<R>, num: usize) -> Result<String> {
let mut lines = String::new();
for _ in 0..num {
bread.read_line(&mut lines)?;
}
if lines.ends_with("\r\n") {
lines.truncate(lines.len() - 2);
} else if lines.ends_with("\n") {
lines.truncate(lines.len() - 1);
} else {
return Err(ParseError::NotEnoughData.into());
}
Ok(lines)
}
macro_rules! parse {
($arg:expr) => {
parse!($arg, _)
};
($arg:expr, $t:ty) => {
match from_utf8($arg)
.map_err(|_| ParseError::InvalidHeader)?
.parse::<$t>()
{
Ok(res) => Some(res),
Err(_) => {
return Err(ParseError::InvalidHeader.into());
}
}
};
}
fn parse_header<R: Read>(bread: &mut BufReader<R>) -> Result<Header> {
let header = read_line(bread)?;
let header: Vec<u8> = if header.starts_with(MAGIC_NUMBER) {
header.into_iter().skip(MAGIC_NUMBER.len()).collect()
} else {
return Err(ParseError::InvalidHeader.into());
};
let arguments: Vec<&[u8]> = header
.split(|c| c == &b' ')
.enumerate()
.filter(|(i, x)| *i == 0 || !x.is_empty())
.map(|(_, x)| x)
.collect();
if arguments.len() < 6 || arguments.len() > 9 {
return Err(ParseError::InvalidHeader.into());
}
if arguments[0].is_empty() {
return Err(ParseError::InvalidHeader.into());
}
let mut hard_blank_char: Vec<u8> = Vec::with_capacity(arguments[0].len());
hard_blank_char.extend_from_slice(arguments[0]);
let height: usize = parse!(arguments[1]).ok_or(ParseError::InvalidHeader)?;
let baseline: usize = parse!(arguments[2]).ok_or(ParseError::InvalidHeader)?;
let max_length: usize = parse!(arguments[3]).ok_or(ParseError::InvalidHeader)?;
let old_layout: i32 = parse!(arguments[4]).ok_or(ParseError::InvalidHeader)?;
let print_direction: PrintDirection = if arguments.len() > 6 {
parse!(arguments[6]).ok_or(ParseError::InvalidHeader)?
} else {
PrintDirection::LeftToRight
};
let layout: Layout = if arguments.len() > 7 {
parse!(arguments[7]).ok_or(ParseError::InvalidHeader)?
} else {
full_layout_from_old_layout(old_layout)
};
let codetag_count: Option<u32> = if arguments.len() > 8 {
Some(parse!(arguments[8]).ok_or(ParseError::InvalidHeader)?)
} else {
None
};
let comment: String = {
let comment_lines: usize = parse!(arguments[5]).ok_or(ParseError::InvalidHeader)?;
read_string_lines(bread, comment_lines)?
};
Ok(Header {
hard_blank_char,
height,
baseline,
max_length,
comment,
print_direction,
layout,
codetag_count,
})
}
fn full_layout_from_old_layout(old_layout: i32) -> Layout {
let raw = if old_layout == 0 {
64
} else if old_layout < 0 {
0
} else {
(old_layout as u32 & 31) | 128
};
Layout::from_bits_truncate(raw)
}