From 25491036360a489bc22f9eb0b534d56c0f96dcee Mon Sep 17 00:00:00 2001
From: Moysan Gabriel <gabriel.moysan.1@etudiant.univ-rennes1.fr>
Date: Mon, 3 Apr 2023 22:48:22 +0200
Subject: [PATCH] open_file impl

---
 src/filesys/filehdr.rs  |  12 +++
 src/filesys/openfile.rs | 161 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 173 insertions(+)

diff --git a/src/filesys/filehdr.rs b/src/filesys/filehdr.rs
index e6dcad9..e0b6be1 100644
--- a/src/filesys/filehdr.rs
+++ b/src/filesys/filehdr.rs
@@ -20,6 +20,18 @@ pub struct FileHdr {
 
 impl FileHdr { 
 
+    //Juste histoire d'avoir un constructeur, temporaire
+    pub fn new() -> FileHdr {
+        FileHdr{
+            is_dir : 0,
+            num_bytes : 0,
+            num_sectors : 0,
+            data_sectors : Vec::new(),
+            num_header_sectors : 0,
+            header_sectors : [0 ; MAX_HEADER_SECTORS as usize]
+        }
+    }
+
     pub fn allocate(&mut self, mut free_map: BitMap, file_size: i32) -> bool {
         self.num_bytes = file_size;
         if file_size > MAX_FILE_LENGTH {
diff --git a/src/filesys/openfile.rs b/src/filesys/openfile.rs
index e69de29..deafa89 100644
--- a/src/filesys/openfile.rs
+++ b/src/filesys/openfile.rs
@@ -0,0 +1,161 @@
+
+use crate::{simulator::{self, disk}, drivers::drv_disk::{DrvDisk, self}};
+
+use super::filehdr::FileHdr;
+
+
+pub const MAX_FILE_NAME_SIZE : i32 = 500;
+
+pub struct OpenFile {
+    pub name : String, // the file's
+    pub hdr : FileHdr, // Header for this file
+    pub seekPosition : i32, // Current position in the file (in byte)
+    pub fSector : i32 // this file first sector on the disk (fichiers stockés de maniere contigue)
+}
+
+//division arrondie vers le bas
+pub fn div_round_down(a : i32, b : i32) -> i32{
+    a/b
+}
+
+//division arrondie vers le haut
+pub fn div_round_up(a : i32, b : i32) -> i32{
+    let mut result = a/b;
+
+    if a%b > 0 {
+        result + 1
+    }
+    else {
+        result
+    }
+}
+
+
+impl OpenFile {
+
+    /*
+    Creer un "fichier ouvert", charge le file_hdr depuis disk
+     */
+    pub fn open_file(sector : i32) -> OpenFile{
+        let file_hdr : FileHdr = FileHdr::new();
+        let name : String = String::from("");
+
+        //ici appel a fetchFrom(sector) sur file_hdr
+
+        OpenFile { name: name, 
+            hdr: file_hdr, 
+            seekPosition: 0, 
+            fSector: sector }
+    }
+
+    pub fn seek(file : &mut OpenFile, position : i32){
+        file.seekPosition = position;
+    }
+
+    /* params : 
+    into : buffer de reception
+    num_bytes : nombre d'octets à lire
+    position : position du premier octet à lire dans le fichier (header compté??)
+     */
+    pub fn read_at(driver_disk : &mut DrvDisk, file : &mut OpenFile, into : &mut Vec<u8>, num_bytes : i32, position : i32) -> i32 {
+
+        let mut nbr_octet_lu = num_bytes;
+        let file_length = file.hdr.file_length(); 
+        let mut first_sector : i32;
+        let mut last_sector : i32;   
+        let mut num_sectors : i32;   
+        let mut start : i32;
+        let mut end : i32; 
+
+        if ( num_bytes <= 0)||( position < 0)||( position >= file_length) {
+            return 0;
+        }
+
+        if (position + num_bytes > file_length) {
+           nbr_octet_lu = file_length - position; 
+        }
+
+        first_sector = div_round_down(position,disk::SECTOR_SIZE);
+        last_sector = div_round_up(position + num_bytes - 1, disk::SECTOR_SIZE);
+        num_sectors = last_sector - first_sector + 1;
+
+        let mut buffer = vec![0_u8; (num_sectors * disk::SECTOR_SIZE) as usize];
+        let mut sector_buffer = vec![0_u8; disk::SECTOR_SIZE as usize];
+
+        for i in first_sector..(last_sector + 1){
+            
+            DrvDisk::read_sector(driver_disk, i, &mut sector_buffer);
+
+            for j in 0..sector_buffer.len(){
+                buffer.push(sector_buffer[j]);
+            }
+        }
+
+        start = position%disk::SECTOR_SIZE;
+        end = start + nbr_octet_lu - 1;
+
+        for i in start..(end + 1){
+            into.push(buffer[i as usize]);
+        }
+
+        nbr_octet_lu
+    }
+
+
+    /* params : 
+    from : données à écrire
+    num_bytes : nombre d'octets à écrire depuis from
+    position : position du premier octet à écrire dans le fichier(header compté??)
+     */
+    pub fn write_at(driver_disk : &mut DrvDisk, file : &mut OpenFile, from : &mut Vec<u8>, num_bytes : i32, position : i32) -> i32 {
+        
+        let mut nbr_octet_ecrit = num_bytes;
+        let mut file_length = file.hdr.file_length();
+        let mut max_file_length = file.hdr.max_file_length();
+
+        let mut first_sector : i32;
+        let mut last_sector : i32;
+        let mut nbr_sectors : i32;
+
+        let mut first_aligned : bool;
+        let mut last_aligned : bool;
+
+        if (num_bytes <= 0)||(position < 0) ||(position > file_length){
+            return 0;
+        }
+
+        if num_bytes + file_length > max_file_length {
+        /*
+        PARTIE MANQUANTE : allocation de nouveau secteurs si fichier trop petit pour l'ecriture
+         need FetchFrom
+         */
+        }
+        else if position + num_bytes > file_length{
+            file.hdr.change_file_length(position + num_bytes);
+        }
+        0
+    }
+
+    pub fn read(driver_disk : &mut DrvDisk, file : &mut OpenFile, into : &mut Vec<u8>, num_bytes : i32) -> i32 {
+
+        let result = OpenFile::read_at(driver_disk, file, into, num_bytes, file.seekPosition);
+        file.seekPosition += result;
+        result
+    }
+
+    pub fn write(driver_disk : &mut DrvDisk, file : &mut OpenFile, from : &mut Vec<u8>, num_bytes : i32) -> i32 {
+        
+        let result = OpenFile::write_at(driver_disk, file, from, num_bytes, file.seekPosition);
+        file.seekPosition += result;
+        result
+    }
+}
+
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+ 
+}
\ No newline at end of file