transfert file from zip to another (wip)

apk_frauder/src/zip_writer.rs

@@ -0,0 +1,73 @@
+use std::io::{Read, Seek, SeekFrom, Write};
+
+use crate::{
+    end_of_central_directory::EndCentralDirectory,
+    end_of_central_directory::Zip64EndCentralDirectory, FileInfo, ZipFileReader,
+};
+use androscalpel_serializer::Serializable;
+
+pub struct ZipFileWriter<T: Write> {
+    files: Vec<FileInfo>,
+    zip64_end_of_central_directory: Option<Zip64EndCentralDirectory>,
+    current_offset: u64,
+    data: T,
+}
+
+impl<T: Write> ZipFileWriter<T> {
+    pub fn new(writer: T, zip64_info: Option<Zip64EndCentralDirectory>) -> Self {
+        Self {
+            current_offset: 0,
+            zip64_end_of_central_directory: zip64_info,
+            files: vec![],
+            data: writer,
+        }
+    }
+
+    /// Insert an file from an existing zip
+    pub fn insert_file_from_zip<U: Read + Seek>(
+        &mut self,
+        mut file_info: FileInfo,
+        zip_file: &mut ZipFileReader<U>,
+    ) {
+        let file_off = file_info.get_file_offset();
+        let file_size = file_info.get_compressed_size();
+        file_info.set_offset_local_header(self.current_offset);
+        file_info.local_header.serialize(&mut self.data).unwrap();
+        zip_file.data.seek(SeekFrom::Start(file_off)).unwrap();
+        let mut remaining_size = file_size;
+        let mut buffer = [0u8; 4096];
+        while remaining_size != 0 {
+            let read = zip_file
+                .data
+                .read(&mut buffer[0..core::cmp::min(4096, remaining_size as usize)])
+                .unwrap();
+            self.data.write_all(&buffer[0..read]).unwrap();
+            remaining_size -= read as u64;
+        }
+        self.current_offset += file_info.local_header.size() as u64 + file_size;
+        self.files.push(file_info);
+    }
+
+    /// Finish the zip file by writing the central directory.
+    pub fn write_central_directory(&mut self) {
+        for file_info in &self.files {
+            file_info.header.serialize(&mut self.data).unwrap();
+        }
+        // TODO: zip64
+        EndCentralDirectory {
+            disk_number: 0,
+            disk_number_of_central_directory_start: 0,
+            number_of_entries_in_central_directory_on_disk: self.files.len() as u16,
+            number_of_entries_in_central_directory: self.files.len() as u16,
+            size_central_directory: self
+                .files
+                .iter()
+                .map(|file| file.local_header.size() as u32 + file.get_compressed_size() as u32)
+                .sum(),
+            offset_central_directory: self.current_offset as u32,
+            comment: vec![],
+        }
+        .serialize(&mut self.data)
+        .unwrap();
+    }
+}