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use crate::*;
use std::collections::BTreeMap;
/// Convert source html to PDF using Writer w.
pub fn html(w: &mut Writer, source: &[u8]) {
let mut p = Parser::new(source);
p.read_token();
html_inner(w, &mut p, b"");
}
#[derive(Debug)]
enum Token {
Text,
Tag,
WhiteSpace,
Eof,
}
struct Parser<'a> {
source: &'a [u8],
position: usize,
token_start: usize,
token_end: usize,
end_tag: bool,
token: Token,
attr: BTreeMap<&'a [u8], &'a [u8]>,
}
impl<'a> Parser<'a> {
fn new(source: &'a [u8]) -> Self {
Self {
source,
position: 0,
token_start: 0,
token_end: 0,
end_tag: false,
token: Token::Eof,
attr: BTreeMap::new(),
}
}
fn tvalue(&self) -> &'a [u8] {
&self.source[self.token_start..self.token_end]
}
/// Get attribute value,
fn avalue(&self, name: &'a [u8]) -> Option<&&'a [u8]> {
self.attr.get(name)
}
/// Get integer attribute, return None on not present or error.
fn aint(&self, name: &'a [u8]) -> Option<Px> {
if let Some(s) = self.avalue(name)
&& let Ok(x) = tos(s).parse::<Px>()
{
return Some(x);
}
None
}
fn next(&mut self) -> u8 {
if self.position == self.source.len() {
0
} else {
let c = self.source[self.position];
self.position += 1;
c
}
}
fn next_non_space(&mut self) -> u8 {
loop {
let c = self.next();
if c != b' ' {
return c;
}
}
}
fn read_tag_attributes(&mut self) {
// Example: width = 15 alt = "something" src = "something" >
loop {
let mut c = self.next_non_space();
let attr_name_start = self.position - 1;
while c != b'=' && c != b' ' && c != b'>' && c != 0 {
c = self.next();
}
if c == b'>' {
return;
}
let attr_name = &self.source[attr_name_start..self.position - 1];
if c == b' ' {
c = self.next_non_space();
}
if c != b'=' {
return;
}
c = self.next_non_space();
let start = self.position - 1;
let attr = if c == b'"' {
// Read quoted attribute
c = self.next();
while c != b'"' && c != 0 {
c = self.next();
}
if c != b'"' {
return;
}
&self.source[start + 1..self.position - 1]
} else {
// Read unquoted attribute
while c != b' ' && c != b'>' && c != 0 {
c = self.next();
}
&self.source[start..self.position - 1]
};
self.attr.insert(attr_name, attr);
if c == b'>' {
return;
}
}
}
fn read_token(&mut self) {
let c = self.next();
if c == 0 {
self.token = Token::Eof;
} else if c == b' ' || c == b'\n' {
self.token = Token::WhiteSpace;
loop {
let c = self.next();
if c != b' ' || c != b'\n' {
if c != 0 {
self.position -= 1;
}
break;
}
}
} else if c == b'<' {
// e.g. <h1 name=x> or </h1>
self.token = Token::Tag;
self.token_start = self.position;
self.end_tag = false;
let mut c = self.next();
if c == b'/' {
self.end_tag = true;
self.token_start = self.position;
c = self.next();
}
loop {
// To find end of tag name
if c == b' ' {
self.token_end = self.position - 1;
self.read_tag_attributes();
break;
} else if c == b'>' {
self.token_end = self.position - 1;
break; // No attributes to parse
} else if c == 0 {
self.token = Token::Eof; // Error
return;
} else {
c = self.next();
}
}
} else {
self.token = Token::Text;
self.token_start = self.position - 1;
let mut c = self.next();
loop {
if c == b'<' || c == b' ' || c == b'\n' {
self.position -= 1;
self.token_end = self.position;
break;
} else if c == 0 {
self.token_end = self.position;
break;
}
c = self.next();
}
}
}
}
fn html_inner(w: &mut Writer, p: &mut Parser, endtag: &[u8]) {
loop {
match p.token {
Token::Eof => {
return;
}
Token::WhiteSpace => {
w.space();
p.read_token();
}
Token::Text => {
let s = tos(p.tvalue());
let s = &html_escape::decode_html_entities(s);
w.text(s);
p.read_token();
}
Token::Tag => {
let tag = p.tvalue();
if p.end_tag {
if tag == endtag {
p.read_token();
}
return;
} else if tag == b"p" && tag == endtag {
return;
}
p.read_token();
if tag == b"br" || tag == b"br/" {
w.output_line();
} else if tag == b"img" {
if let Some(src) = p.avalue(b"src") {
let width = p.aint(b"width");
let height = p.aint(b"height");
w.image(tos(src), width, height);
}
} else {
let save_mode = w.mode;
let save_font = w.cur_font;
let save_font_size = w.font_size;
let mut save: Px = 0;
match tag {
b"p" => w.output_line(),
b"h1" => {
w.font_size = 14;
w.output_line();
save = if w.center { 1 } else { 0 };
w.center = true;
}
b"b" => w.cur_font |= 1,
b"i" => w.cur_font |= 2,
b"title" => w.mode = Mode::Title,
b"html" | b"head" => w.mode = Mode::Head,
b"body" => w.mode = Mode::Normal,
b"sup" => {
save = w.sup;
w.set_sup(w.font_size / 2);
}
b"sub" => {
save = w.sup;
w.set_sup(-w.font_size / 2);
}
_ => {}
}
html_inner(w, p, tag);
w.mode = save_mode;
w.font_size = save_font_size;
w.cur_font = save_font;
match tag {
b"sup" | b"sub" => w.set_sup(save),
b"h1" => {
w.output_line();
w.center = save == 1;
}
_ => {}
}
}
}
}
}
}
/// Convert byte slice into string.
fn tos(s: &[u8]) -> &str {
std::str::from_utf8(s).unwrap()
}