Update Readme and add utility functions

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdflib"
-version = "0.1.4"
+version = "0.1.5"
 authors = ["trivernis <trivernis@gmail.com>"]
 edition = "2018"
 license-file = "LICENSE"

README.md

@@ -2,6 +2,54 @@
 
 This library provides methods to read and write Binary Dictionary Format files that can be used to represent rainbow tables.
 
+## Usage
+
+### Read
+
+```rust
+use bdf::io::BDFReader;
+use std::fs::File;
+use std::io::BufReader;
+
+fn main() {
+    let f = File::open("dictionary.bdf").unwrap();
+    let buf_reader = BufReader::new(f);
+    let mut bdf_reader = BDFReader::new(buf_reader);
+    bdf_reader.read_metadata().unwrap();
+    let lookup_table = bdf_reader.read_lookup_table().unwrap();
+    let lookup_table = lookup_table.clone();
+    while let Ok(next_chunk) = &mut bdf_reader.next_chunk() {
+        if let Ok(entries) = next_chunk.data_entries(&lookup_table) {
+            println!("{:?}", entries);
+        }
+    }
+}
+```
+
+### Write
+
+```rust
+use bdf::chunks::{DataEntry, HashEntry};
+use bdf::io::BDFWriter;
+use std::fs::File;
+use std::io::BufWriter;
+use std::convert::Into;
+
+fn main() {
+    let f = File::create("dictionary.bdf").unwrap();
+    let buf_writer = BufWriter::new(f);
+    let entry_count = 1;
+    let mut bdf_writer = BDFWriter::new(buf_writer, entry_count, false);
+    bdf_writer.add_lookup_entry(HashEntry::new("fakehash".into(), 3)).unwrap();
+    let mut entry = DataEntry::new("foo".into());
+    entry.add_hash_value("fakehash".into(), vec![0, 2, 3]);
+    bdf_writer.add_data_entry(entry).unwrap();
+    bdf_writer.flush().unwrap();
+    bdf_writer.flush_writer().unwrap();
+    println!("Finished writing!");
+}
+```
+
 ## Binary Dictionary File Format (bdf)
 
 ```

src/io.rs

@@ -1,14 +1,13 @@
 use super::chunks::*;
-use std::io::{Write, BufWriter, ErrorKind, BufReader, Read};
-use std::fs::File;
-use std::collections::HashMap;
-use std::io::Error;
 use byteorder::{BigEndian, ByteOrder};
+use std::collections::HashMap;
 use std::convert::TryInto;
+use std::fs::File;
+use std::io::Error;
+use std::io::{BufReader, BufWriter, ErrorKind, Read, Write};
 
 const ENTRIES_PER_CHUNK: u32 = 100_000;
 
-
 pub struct BDFReader {
     reader: BufReader<File>,
     pub metadata: Option<MetaChunk>,
@@ -16,7 +15,6 @@ pub struct BDFReader {
     compressed: bool,
 }
 
-
 pub struct BDFWriter {
     writer: BufWriter<File>,
     metadata: MetaChunk,
@@ -28,7 +26,14 @@ pub struct BDFWriter {
 }
 
 impl BDFWriter {
-    
+    /// Creates a new BDFWriter.
+    /// The number for `entry_count` should be the total number of entries
+    /// This is required since the META chunk containing the information is the
+    /// first chunk to be written.
+    /// The number of entries can be used in tools that provide a progress
+    /// bar for how many entries were read.
+    /// If the `compress` parameter is true, each data chunk will be compressed
+    /// using lzma with a default level of 1.
     pub fn new(writer: BufWriter<File>, entry_count: u64, compress: bool) -> Self {
         Self {
             metadata: MetaChunk::new(entry_count, ENTRIES_PER_CHUNK, compress),
@@ -70,7 +75,6 @@ impl BDFWriter {
     }
 
     /// Writes the data to the file
-    
     pub fn flush(&mut self) -> Result<(), Error> {
         if !self.head_written {
             self.writer.write(BDF_HDR)?;
@@ -98,6 +102,15 @@ impl BDFWriter {
         self.writer.flush()
     }
 
+    /// Flushes the buffered chunk data and the writer
+    /// to finish the file.
+    pub fn finish(&mut self) -> Result<(), Error> {
+        self.flush()?;
+        self.flush_writer()?;
+
+        Ok(())
+    }
+
     /// Sets the compression level for lzma compression
     pub fn set_compression_level(&mut self, level: u32) {
         self.compression_level = level;
@@ -107,16 +120,19 @@ impl BDFWriter {
     /// Returns an error if the metadata has already been written.
     pub fn set_entries_per_chunk(&mut self, number: u32) -> Result<(), Error> {
         if self.head_written {
-            return Err(Error::new(ErrorKind::Other, "the head has already been written"))
+            return Err(Error::new(
+                ErrorKind::Other,
+                "the head has already been written",
+            ));
         }
         self.metadata.entries_per_chunk = number;
-        self.metadata.chunk_count = (self.metadata.entry_count as f64 / number as f64).ceil() as u32;
+        self.metadata.chunk_count =
+            (self.metadata.entry_count as f64 / number as f64).ceil() as u32;
         Ok(())
     }
 }
 
 impl BDFReader {
-
     /// Creates a new BDFReader
     pub fn new(reader: BufReader<File>) -> Self {
         Self {
@@ -127,6 +143,14 @@ impl BDFReader {
         }
     }
 
+    /// Reads the metadata and lookup table
+    pub fn read_start(&mut self) -> Result<(), Error> {
+        self.read_metadata()?;
+        self.read_lookup_table()?;
+
+        Ok(())
+    }
+
     /// Verifies the header of the file and reads and stores the metadata
     pub fn read_metadata(&mut self) -> Result<&MetaChunk, Error> {
         if !self.validate_header() {

src/lib.rs

@@ -2,10 +2,10 @@
 mod tests {
 
     use super::io::BDFWriter;
-    use std::io::{BufWriter, Error, BufReader};
-    use std::fs::{File, remove_file};
-    use crate::chunks::{HashEntry, DataEntry};
+    use crate::chunks::{DataEntry, HashEntry};
     use crate::io::BDFReader;
+    use std::fs::{remove_file, File};
+    use std::io::{BufReader, BufWriter, Error};
 
     const FOO: &str = "foo";
     const BAR: &str = "bar";
@@ -53,8 +53,7 @@ mod tests {
         entry_2.add_hash_value(FOO.to_string(), vec![4, 5, 2, 3]);
         writer.add_data_entry(entry_2)?;
 
-        writer.flush()?;
-        writer.flush_writer()?;
+        writer.finish()?;
 
         remove_file("tmp2.bdf")?;
 
@@ -65,8 +64,8 @@ mod tests {
     fn it_reads() -> Result<(), Error> {
         create_simple_file("tmp3.bdf", false)?;
         let mut reader = new_reader("tmp3.bdf")?;
-        reader.read_metadata()?;
-        let lookup_table = &reader.read_lookup_table()?.clone();
+        reader.read_start()?;
+        let lookup_table = &reader.lookup_table.clone().unwrap();
         let mut next_chunk = reader.next_chunk()?;
         let data_entries = next_chunk.data_entries(lookup_table)?;
         assert_eq!(data_entries[0].plain, "lol".to_string());