gonna make a reader

.gitignore

@@ -0,0 +1,2 @@
+/target
+Cargo.lock

Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "pdf_parser"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.44"
+rev_lines = "0.2.1"

measure

@@ -0,0 +1,6 @@
+%PDF-1.6
+%<25><><EFBFBD><EFBFBD>
+124332 0 obj
+<</Linearized 1/L 8995189/O 124334/E 49521/N 756/T 8983957/H [ 2916 7320]>>
+endobj
+  

src/lib.rs

@@ -0,0 +1,119 @@
+mod structs;
+
+use anyhow::Result;
+use rev_lines::RevLines;
+use std::collections::HashMap;
+use std::io::BufRead;
+use std::io::BufReader;
+use std::io::Read;
+
+enum Token {}
+
+enum Value {
+	None,
+	Num,
+	Ident(String),
+	String(Vec<u8>),
+	Stream(Vec<u8>),
+	Object(HashMap<String, Box<Value>>),
+}
+struct Lexer<'a> {
+	source: &'a [u8],
+	limit: Option<usize>,
+	state: Value,
+}
+
+impl<'a> Lexer<'a> {
+	fn lex(&mut self) -> Result<Vec<Token>> {
+		let mut output = vec![];
+
+		for c in self.source.iter() {
+			match *c as char {
+				'/' => match self.state {
+					Value::None => todo!(),
+					Value::Num => todo!(),
+					Value::Ident(_) => todo!(),
+					Value::String(_) => todo!(),
+					Value::Stream(_) => todo!(),
+					Value::Object(_) => todo!(),
+				},
+				x => unimplemented!["{}", x],
+			}
+		}
+
+		Ok(output)
+	}
+}
+
+// #[derive(Debug, PartialEq, Eq, Clone, PartialOrd, Ord)]
+// struct Object {
+// 	id: u64,
+// 	version: u64,
+// 	header: HashMap<String, >,
+// }
+
+enum State {
+	Start,
+	FoundEof,
+	FoundStartXref,
+	FoundXrefOffset,
+}
+
+pub fn parse(file: std::fs::File) -> Result<()> {
+	let mut reader = RevLines::new(BufReader::new(file))?;
+	let mut offset_to_trailer = 0u64;
+	let mut found_eof = false;
+	let mut forwards = false;
+	let mut state = State::Start;
+
+	reader.;
+
+	while let Ok(Some(line)) = if forwards {
+		reader.next_line()
+	} else {
+		reader.prev_line()
+	} {
+		match state {
+			State::Start => {
+				if line.contains("%%EOF") {
+					state = State::FoundEof;
+					continue;
+				}
+			}
+			State::FoundEof => {
+				if line.contains("startxref") {
+					state = State::FoundStartXref;
+					forwards = true;
+					continue;
+				}
+			}
+			State::FoundStartXref => {
+				state = State::FoundXrefOffset;
+				offset_to_trailer = line.parse::<u64>()?;
+			}
+			State::FoundXrefOffset => {
+				reader.seek();
+			}
+		}
+	}
+
+	Ok(())
+}
+
+#[test]
+fn open_a_file() -> Result<()> {
+	let the_pdf = std::fs::File::open("1005.1497.pdf")?;
+
+	parse(the_pdf);
+
+	Ok(())
+}
+
+#[test]
+fn open_another_file() -> Result<()> {
+	let the_pdf = std::fs::File::open("PDF32000_2008.pdf")?;
+
+	parse(the_pdf);
+
+	Ok(())
+}