10 files changed, 269 insertions, 75 deletions

diff --git a/src/archive.rs b/src/archive.rs
index e17db80..73c515c 100644
--- a/src/archive.rs
+++ b/src/archive.rs
@@ -48,11 +48,31 @@ where
         self.get_file_info_by_index(self.get_file_index(name)?)
     }
 
+    fn get_file_reader_by_index_with_optional_password<'d>(
+        &'d mut self,
+        index: usize,
+        password: Option<&str>,
+    ) -> ArchiveResult<ArchiveFile<D::FileReader<'d>>, D::Error> {
+        Ok(ArchiveFile::new(
+            self.driver.get_file_reader(index, password)?,
+        ))
+    }
+
+    #[inline]
     pub fn get_file_reader_by_index<'d>(
         &'d mut self,
         index: usize,
     ) -> ArchiveResult<ArchiveFile<D::FileReader<'d>>, D::Error> {
-        Ok(ArchiveFile::new(self.driver.get_file_reader(index)?))
+        self.get_file_reader_by_index_with_optional_password(index, None)
+    }
+
+    #[inline]
+    pub fn get_file_reader_by_index_with_password<'d>(
+        &'d mut self,
+        index: usize,
+        password: &str,
+    ) -> ArchiveResult<ArchiveFile<D::FileReader<'d>>, D::Error> {
+        self.get_file_reader_by_index_with_optional_password(index, Some(password))
     }
 
     #[inline]
@@ -60,7 +80,19 @@ where
         &'d mut self,
         name: &str,
     ) -> ArchiveResult<ArchiveFile<D::FileReader<'d>>, D::Error> {
-        self.get_file_reader_by_index(self.get_file_index(name)?)
+        self.get_file_reader_by_index_with_optional_password(self.get_file_index(name)?, None)
+    }
+
+    #[inline]
+    pub fn get_file_reader_by_name_with_password<'d>(
+        &'d mut self,
+        name: &str,
+        password: &str,
+    ) -> ArchiveResult<ArchiveFile<D::FileReader<'d>>, D::Error> {
+        self.get_file_reader_by_index_with_optional_password(
+            self.get_file_index(name)?,
+            Some(password),
+        )
     }
 }
 
diff --git a/src/driver/driver.rs b/src/driver/driver.rs
index 747345c..f0f93a9 100644
--- a/src/driver/driver.rs
+++ b/src/driver/driver.rs
@@ -34,6 +34,7 @@ where
     fn get_file_reader<'d>(
         &'d mut self,
         index: usize,
+        password: Option<&str>,
     ) -> ArchiveResult<Self::FileReader<'d>, Self::Error>;
 }
 
diff --git a/src/utils/cursor.rs b/src/utils/cursor.rs
index 0c4b77e..91d44f8 100644
--- a/src/utils/cursor.rs
+++ b/src/utils/cursor.rs
@@ -34,7 +34,6 @@ impl<Io: Write> Write for IoCursor<Io> {
         Ok(bytes)
     }
 
-    #[inline]
     fn flush(&mut self) -> Result<()> {
         self.io.flush()
     }
diff --git a/src/zip/driver.rs b/src/zip/driver.rs
index 0905d9a..87f9c1a 100644
--- a/src/zip/driver.rs
+++ b/src/zip/driver.rs
@@ -3,7 +3,8 @@ use crate::utils::ReadUtils;
 use crate::zip::cp437::FromCp437;
 use crate::zip::structs::{deserialize, Cdr, Eocdr, Eocdr64, Eocdr64Locator, ExtraHeader};
 use crate::zip::{
-    BitFlag, CompressionMethod, ZipError, ZipFileInfo, ZipFileReader, ZipFileWriter, ZipResult,
+    BitFlag, CompressionMethod, EncryptionMethod, ZipError, ZipFileInfo, ZipFileReader,
+    ZipFileWriter, ZipResult,
 };
 use chrono::{DateTime, Local, NaiveDate, NaiveDateTime, NaiveTime};
 use std::collections::HashMap as Map;
@@ -220,6 +221,7 @@ impl<Io: Read + Seek> ArchiveRead for Zip<Io> {
             indexes.insert(name.clone(), i);
             files.push(ZipFileInfo::new(
                 CompressionMethod::from_struct_id(cdr.compression_method)?,
+                EncryptionMethod::from_bit_flag(bit_flag),
                 bit_flag,
                 mtime,
                 atime,
@@ -256,10 +258,15 @@ impl<Io: Read + Seek> ArchiveRead for Zip<Io> {
         self.files.get(index).ok_or(ZipError::FileNotFound.into())
     }
 
-    fn get_file_reader<'d>(&'d mut self, index: usize) -> ZipResult<Self::FileReader<'d>> {
+    fn get_file_reader<'d>(
+        &'d mut self,
+        index: usize,
+        password: Option<&str>,
+    ) -> ZipResult<Self::FileReader<'d>> {
         Ok(ZipFileReader::new(
             &mut self.io,
             self.files.get(index).ok_or(ZipError::FileNotFound)?,
+            password,
         )?)
     }
 }
diff --git a/src/zip/encryption.rs b/src/zip/encryption.rs
new file mode 100644
index 0000000..84e30d5
--- /dev/null
+++ b/src/zip/encryption.rs
@@ -0,0 +1,62 @@
+use crate::utils::ReadUtils;
+use crate::zip::ZipResult;
+use crc32fast::Hasher;
+use std::io::{Read, Result as IoResult};
+
+fn crc32(byte: u8, crc32: u32) -> u32 {
+    let mut hasher = Hasher::new_with_initial(crc32 ^ 0xFFFFFFFF);
+    hasher.update(&[byte]);
+    hasher.finalize() ^ 0xFFFFFFFF
+}
+
+pub struct WeakDecoder<Io: Read> {
+    key0: u32,
+    key1: u32,
+    key2: u32,
+    io: Io,
+}
+
+impl<Io: Read> WeakDecoder<Io> {
+    pub fn new(io: Io, password: &str) -> ZipResult<Self> {
+        let mut decoder = Self {
+            key0: 305419896,
+            key1: 591751049,
+            key2: 878082192,
+            io,
+        };
+
+        for c in password.chars() {
+            decoder.update_keys(c as u8)
+        }
+
+        let buf = decoder.read_arr::<12>()?;
+
+        Ok(decoder)
+    }
+
+    fn update_keys(&mut self, byte: u8) {
+        self.key0 = crc32(byte, self.key0);
+        self.key1 = self
+            .key1
+            .wrapping_add(self.key0 & 0xFF)
+            .wrapping_mul(134775813)
+            .wrapping_add(1);
+        self.key2 = crc32((self.key1 >> 24) as u8, self.key2);
+    }
+
+    fn decode_byte(&mut self, byte: u8) -> u8 {
+        let key = self.key2 | 2;
+        byte ^ (((key * (key ^ 1)) >> 8) as u8)
+    }
+}
+
+impl<Io: Read> Read for WeakDecoder<Io> {
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
+        let bytes = self.io.read(buf)?;
+        for i in 0..bytes {
+            buf[i] = self.decode_byte(buf[i]);
+            self.update_keys(buf[i])
+        }
+        Ok(bytes)
+    }
+}
diff --git a/src/zip/error.rs b/src/zip/error.rs
index 3eb68b8..9ec0956 100644
--- a/src/zip/error.rs
+++ b/src/zip/error.rs
@@ -11,15 +11,18 @@ pub enum ZipError {
     InvalidFileHeaderSignature,
     InvalidCDRSignature,
 
-    InvalidCompressionMethod,
-    UnsupportedCompressionMethod,
+    InvalidCompressionMethod(u16),
+    UnsupportedCompressionMethod(u16),
+    UnsupportedEncryptionMethod,
     InvalidDate,
     InvalidTime,
     InvalidFileName,
     InvalidFileComment,
 
     FileNotFound,
+    PasswordIsNotSpecified,
     CompressedDataIsUnseekable,
+    EncryptedDataIsUnseekable,
 }
 
 impl From<ZipError> for ArchiveError<ZipError> {
@@ -48,15 +51,24 @@ impl Display for ZipError {
                 write!(f, "Invalid signature of central directory record")
             }
 
-            Self::InvalidCompressionMethod => writeln!(f, "Invalid compression method"),
-            Self::UnsupportedCompressionMethod => writeln!(f, "Unsupported compression method"),
+            Self::InvalidCompressionMethod(id) => {
+                writeln!(f, "Invalid compression method {}", id)
+            }
+            Self::UnsupportedCompressionMethod(id) => {
+                writeln!(f, "Unsupported compression method {}", id)
+            }
+            Self::UnsupportedEncryptionMethod => {
+                writeln!(f, "Unsupported encryption method")
+            }
             Self::InvalidDate => write!(f, "Invalid date"),
             Self::InvalidTime => write!(f, "Invalid time"),
             Self::InvalidFileName => write!(f, "Invalid file name"),
             Self::InvalidFileComment => write!(f, "Invalid file comment"),
 
             Self::FileNotFound => write!(f, "File not found"),
+            Self::PasswordIsNotSpecified => write!(f, "Password is not specified"),
             Self::CompressedDataIsUnseekable => write!(f, "Compressed data is unseekable"),
+            Self::EncryptedDataIsUnseekable => write!(f, "Encrypted data is unseekable"),
         }
     }
 }
diff --git a/src/zip/file/info.rs b/src/zip/file/info.rs
index 4e1b293..f5d4d8a 100644
--- a/src/zip/file/info.rs
+++ b/src/zip/file/info.rs
@@ -2,7 +2,7 @@ use crate::driver::ArchiveFileInfo;
 use crate::zip::{ZipError, ZipResult};
 use chrono::{DateTime, Local};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum CompressionMethod {
     Store,
     Deflate,
@@ -10,31 +10,49 @@ pub enum CompressionMethod {
     Lzma,
     Zstd,
     Xz,
-    Unsupported,
+    Unsupported(u16),
 }
 
 impl CompressionMethod {
     pub(crate) fn from_struct_id(id: u16) -> ZipResult<Self> {
-        match id {
-            0 => Ok(Self::Store),
-            8 => Ok(Self::Deflate),
-            12 => Ok(Self::BZip2),
-            14 => Ok(Self::Lzma),
-            93 => Ok(Self::Zstd),
-            95 => Ok(Self::Xz),
-            1..=7 | 9..=11 | 13 | 15..=20 | 94 | 96..=99 => Ok(Self::Unsupported),
-            21..=92 | 100.. => Err(ZipError::InvalidCompressionMethod.into()),
+        Ok(match id {
+            0 => Self::Store,
+            8 => Self::Deflate,
+            12 => Self::BZip2,
+            14 => Self::Lzma,
+            93 => Self::Zstd,
+            95 => Self::Xz,
+            1..=7 | 9..=11 | 13 | 15..=20 | 94 | 96..=99 => Self::Unsupported(id),
+            21..=92 | 100.. => return Err(ZipError::InvalidCompressionMethod(id).into()),
+        })
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum EncryptionMethod {
+    None,
+    Weak,
+    Unsupported,
+}
+
+impl EncryptionMethod {
+    pub(crate) fn from_bit_flag(bit_flag: BitFlag) -> EncryptionMethod {
+        match (bit_flag.is_encrypted(), bit_flag.is_strong_encryption()) {
+            (false, false) => EncryptionMethod::None,
+            (true, false) => EncryptionMethod::Weak,
+            (true, true) => EncryptionMethod::Unsupported,
+            _ => panic!("impossible"),
         }
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub struct BitFlag {
     flag: u16,
 }
 
 pub mod bit {
-    #[derive(Debug, PartialEq, Eq)]
+    #[derive(Debug, PartialEq, Eq, Clone, Copy)]
     pub enum DeflateMode {
         Normal,
         Maximum,
@@ -123,6 +141,7 @@ impl BitFlag {
 #[derive(Debug, Clone)]
 pub struct ZipFileInfo {
     pub compression_method: CompressionMethod,
+    pub encryption_method: EncryptionMethod,
     pub bit_flag: BitFlag,
     pub mtime: DateTime<Local>,
     pub atime: Option<DateTime<Local>>,
@@ -138,6 +157,7 @@ pub struct ZipFileInfo {
 impl ZipFileInfo {
     pub fn new(
         compression_method: CompressionMethod,
+        encryption_method: EncryptionMethod,
         bit_flag: BitFlag,
         mtime: DateTime<Local>,
         atime: Option<DateTime<Local>>,
@@ -151,6 +171,7 @@ impl ZipFileInfo {
     ) -> Self {
         Self {
             compression_method,
+            encryption_method,
             bit_flag,
             mtime,
             atime,
diff --git a/src/zip/file/mod.rs b/src/zip/file/mod.rs
index 43ccc04..ce3c21d 100644
--- a/src/zip/file/mod.rs
+++ b/src/zip/file/mod.rs
@@ -2,6 +2,6 @@ mod info;
 mod read;
 mod write;
 
-pub use info::{bit, BitFlag, CompressionMethod, ZipFileInfo};
+pub use info::{bit, BitFlag, CompressionMethod, EncryptionMethod, ZipFileInfo};
 pub use read::ZipFileReader;
 pub use write::ZipFileWriter;
diff --git a/src/zip/file/read.rs b/src/zip/file/read.rs
index f5a54f3..aa665c3 100644
--- a/src/zip/file/read.rs
+++ b/src/zip/file/read.rs
@@ -1,6 +1,7 @@
 use crate::driver::FileDriver;
 use crate::utils::{IoCursor, ReadUtils};
-use crate::zip::{CompressionMethod, ZipError, ZipFileInfo, ZipResult};
+use crate::zip::encryption::WeakDecoder;
+use crate::zip::{CompressionMethod, EncryptionMethod, ZipError, ZipFileInfo, ZipResult};
 use bzip2::read::BzDecoder;
 use flate2::read::DeflateDecoder;
 use liblzma::read::XzDecoder;
@@ -10,6 +11,47 @@ use std::io::{
 };
 use zstd::stream::Decoder as ZstdDecoder;
 
+enum Encryption<Io: Read> {
+    None(Io),
+    Weak(WeakDecoder<Io>),
+}
+
+impl<Io: Read> Encryption<Io> {
+    pub fn new(io: Io, method: EncryptionMethod, password: Option<&str>) -> ZipResult<Self> {
+        Ok(match method {
+            EncryptionMethod::None => Self::None(io),
+            EncryptionMethod::Weak => Self::Weak(WeakDecoder::new(
+                io,
+                password.ok_or(ZipError::PasswordIsNotSpecified)?,
+            )?),
+            EncryptionMethod::Unsupported => {
+                return Err(ZipError::UnsupportedEncryptionMethod.into())
+            }
+        })
+    }
+}
+
+impl<Io: Read> Read for Encryption<Io> {
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
+        match self {
+            Self::None(io) => io.read(buf),
+            Self::Weak(io) => io.read(buf),
+        }
+    }
+}
+
+impl<Io: Read + Seek> Seek for Encryption<Io> {
+    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
+        match self {
+            Self::None(io) => io.seek(pos),
+            _ => Err(IoError::new(
+                IoErrorKind::Unsupported,
+                ZipError::EncryptedDataIsUnseekable,
+            )),
+        }
+    }
+}
+
 enum Compression<Io: Read> {
     Store(Io),
     Deflate(DeflateDecoder<Io>),
@@ -18,8 +60,48 @@ enum Compression<Io: Read> {
     Xz(XzDecoder<Io>),
 }
 
+impl<Io: Read + Seek> Compression<Io> {
+    pub fn new(io: Io, method: CompressionMethod) -> ZipResult<Self> {
+        Ok(match method {
+            CompressionMethod::Store => Self::Store(io),
+            CompressionMethod::Deflate => Self::Deflate(DeflateDecoder::new(io)),
+            CompressionMethod::BZip2 => Self::BZip2(BzDecoder::new(io)),
+            CompressionMethod::Lzma => panic!(),
+            CompressionMethod::Zstd => Self::Zstd(ZstdDecoder::new(io)?),
+            CompressionMethod::Xz => Self::Xz(XzDecoder::new(io)),
+            CompressionMethod::Unsupported(id) => {
+                return Err(ZipError::UnsupportedCompressionMethod(id).into())
+            }
+        })
+    }
+}
+
+impl<Io: Read> Read for Compression<Io> {
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
+        match self {
+            Compression::Store(io) => io.read(buf),
+            Compression::Deflate(io) => io.read(buf),
+            Compression::BZip2(io) => io.read(buf),
+            Compression::Zstd(io) => io.read(buf),
+            Compression::Xz(io) => io.read(buf),
+        }
+    }
+}
+
+impl<Io: Read + Seek> Seek for Compression<Io> {
+    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
+        match self {
+            Compression::Store(io) => io.seek(pos),
+            _ => Err(IoError::new(
+                IoErrorKind::Unsupported,
+                ZipError::CompressedDataIsUnseekable,
+            )),
+        }
+    }
+}
+
 pub struct ZipFileReader<'d, Io: Read> {
-    io: Compression<IoCursor<&'d mut Io>>,
+    io: Compression<Encryption<IoCursor<&'d mut Io>>>,
     info: &'d ZipFileInfo,
 }
 
@@ -33,7 +115,7 @@ impl<'d, Io: Read> FileDriver for ZipFileReader<'d, Io> {
 }
 
 impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
-    pub fn new(io: &'d mut Io, info: &'d ZipFileInfo) -> ZipResult<Self> {
+    pub fn new(io: &'d mut Io, info: &'d ZipFileInfo, password: Option<&str>) -> ZipResult<Self> {
         io.seek(SeekFrom::Start(info.header_pointer))?;
 
         let buf = io.read_arr::<30>()?;
@@ -45,27 +127,22 @@ impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
             + u16::from_le_bytes(buf[26..28].try_into().unwrap()) as u64
             + u16::from_le_bytes(buf[28..30].try_into().unwrap()) as u64;
 
+        io.seek(SeekFrom::Start(data_pointer))?;
+
         Ok(Self {
             io: match info.compression_method {
-                CompressionMethod::Store => Compression::Store(IoCursor::new(
-                    io,
-                    data_pointer,
-                    data_pointer + info.compressed_size,
-                )?),
-                CompressionMethod::Deflate => Compression::Deflate(DeflateDecoder::new(
-                    IoCursor::new(io, data_pointer, data_pointer + info.compressed_size)?,
-                )),
-                CompressionMethod::BZip2 => Compression::BZip2(BzDecoder::new(IoCursor::new(
-                    io,
-                    data_pointer,
-                    data_pointer + info.compressed_size,
-                )?)),
                 CompressionMethod::Lzma => {
-                    io.seek(SeekFrom::Start(data_pointer))?;
                     let buf = io.read_arr::<9>()?;
-
                     Compression::Xz(XzDecoder::new_stream(
-                        IoCursor::new(io, data_pointer + 9, data_pointer + info.compressed_size)?,
+                        Encryption::new(
+                            IoCursor::new(
+                                io,
+                                data_pointer + 9,
+                                data_pointer + info.compressed_size,
+                            )?,
+                            info.encryption_method,
+                            password,
+                        )?,
                         Stream::new_raw_decoder(
                             Filters::new().lzma1(
                                 LzmaOptions::new()
@@ -80,30 +157,22 @@ impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
                         .unwrap(),
                     ))
                 }
-                CompressionMethod::Zstd => Compression::Zstd(
-                    ZstdDecoder::new(IoCursor::new(
-                        io,
-                        data_pointer,
-                        data_pointer + info.compressed_size,
-                    )?)
-                    .unwrap(),
-                ),
-                CompressionMethod::Xz => Compression::Xz(XzDecoder::new(IoCursor::new(
-                    io,
-                    data_pointer,
-                    data_pointer + info.compressed_size,
-                )?)),
-                CompressionMethod::Unsupported => {
-                    return Err(ZipError::UnsupportedCompressionMethod.into())
-                }
+                _ => Compression::new(
+                    Encryption::new(
+                        IoCursor::new(io, data_pointer, data_pointer + info.compressed_size)?,
+                        info.encryption_method,
+                        password,
+                    )?,
+                    info.compression_method,
+                )?,
             },
             info,
         })
     }
 
-    pub fn seekable(&self) -> bool {
+    pub fn is_seekable(&self) -> bool {
         match self.io {
-            Compression::Store(..) => true,
+            Compression::Store(Encryption::None(..)) => true,
             _ => false,
         }
     }
@@ -111,24 +180,12 @@ impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
 
 impl<'d, Io: Read> Read for ZipFileReader<'d, Io> {
     fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
-        match &mut self.io {
-            Compression::Store(io) => io.read(buf),
-            Compression::Deflate(io) => io.read(buf),
-            Compression::BZip2(io) => io.read(buf),
-            Compression::Zstd(io) => io.read(buf),
-            Compression::Xz(io) => io.read(buf),
-        }
+        self.io.read(buf)
     }
 }
 
 impl<'d, Io: Read + Seek> Seek for ZipFileReader<'d, Io> {
     fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
-        match &mut self.io {
-            Compression::Store(io) => io.seek(pos),
-            _ => Err(IoError::new(
-                IoErrorKind::Unsupported,
-                ZipError::CompressedDataIsUnseekable,
-            )),
-        }
+        self.io.seek(pos)
     }
 }
diff --git a/src/zip/mod.rs b/src/zip/mod.rs
index bcc34ed..fcc6161 100644
--- a/src/zip/mod.rs
+++ b/src/zip/mod.rs
@@ -1,13 +1,16 @@
 mod archive;
 mod cp437;
 mod driver;
+mod encryption;
 mod error;
 mod file;
 mod structs;
 
 pub use driver::Zip;
 pub use error::{ZipError, ZipResult};
-pub use file::{bit, BitFlag, CompressionMethod, ZipFileInfo, ZipFileReader, ZipFileWriter};
+pub use file::{
+    bit, BitFlag, CompressionMethod, EncryptionMethod, ZipFileInfo, ZipFileReader, ZipFileWriter,
+};
 
 #[cfg(test)]
 mod tests;