From 8d70bb08ca9698791a8e9572c583e15e87aaba95 Mon Sep 17 00:00:00 2001
From: Able <abl3theabove@gmail.com>
Date: Tue, 12 Apr 2022 18:17:48 -0500
Subject: [PATCH] Messaging api done

---
 ableos/src/unicode_utils.rs |   1 +
 kernel/src/lib.rs           |   1 +
 kernel/src/messaging.rs     | 128 +++++++++++++++++++++++++++++++++++-
 3 files changed, 129 insertions(+), 1 deletion(-)

diff --git a/ableos/src/unicode_utils.rs b/ableos/src/unicode_utils.rs
index 22369a2..11c95f0 100644
--- a/ableos/src/unicode_utils.rs
+++ b/ableos/src/unicode_utils.rs
@@ -1,2 +1,3 @@
 pub const CONSOLE: &str = "\u{E795}";
 pub const POWER_SIGN: &str = "\u{23FB}";
+pub const LAMBDA: &str = "λ";
diff --git a/kernel/src/lib.rs b/kernel/src/lib.rs
index 55a56b2..4290210 100644
--- a/kernel/src/lib.rs
+++ b/kernel/src/lib.rs
@@ -3,6 +3,7 @@
 #![deny(missing_docs)]
 #![no_std]
 #![feature(prelude_import)]
+#![feature(arbitrary_enum_discriminant)]
 
 pub mod device_interface;
 pub mod messaging;
diff --git a/kernel/src/messaging.rs b/kernel/src/messaging.rs
index 068919f..044b28a 100644
--- a/kernel/src/messaging.rs
+++ b/kernel/src/messaging.rs
@@ -1,7 +1,22 @@
 //! Interprocess communication.
 
+use alloc::vec::Vec;
+
 use crate::{proccess::PID, time::Time};
 
+extern crate alloc;
+
+/// 131070 * 128
+pub const TINY_MESSAGE_COUNT: usize = 131070;
+/// 16384 * 1024
+pub const SMALL_MESSAGE_COUNT: usize = 16384;
+/// 65536 * 256
+pub const MEDIUM_MESSAGE_COUNT: usize = 256;
+///  262144 * 16
+pub const LARGE_MESSAGE_COUNT: usize = 16;
+/// 16777216 * 4
+pub const HUGE_MESSAGE_COUNT: usize = 4;
+
 /// 128 Bytes
 pub type Tiny = [u8; 128];
 
@@ -54,7 +69,18 @@ pub struct ProcessMessage {
     /// The time the message was received
     pub receiver_time: Time,
 }
-
+impl ProcessMessage {
+    /// Return the size of the message
+    pub fn size(&self) -> usize {
+        match &self.message {
+            Message::Tiny(_) => 128,
+            Message::Small(_) => 1024,
+            Message::Medium(_) => 65536,
+            Message::Large(_) => 1048576,
+            Message::Huge(_) => 16777216,
+        }
+    }
+}
 #[derive(Debug)]
 /// An enum of all possible errors that can occur when sending a message
 pub enum MessagingError {
@@ -65,3 +91,103 @@ pub enum MessagingError {
     /// The message Queue is full
     TooManyMessages,
 }
+
+/// A mailbox that holds messages and PipeState
+pub struct Mailbox {
+    /// The messages in the mailbox
+    pub messages: Vec<ProcessMessage>,
+    /// The count of messages in the mailbox
+    pub message_count: MessageCount,
+}
+impl Mailbox {
+    /// append a message to the mailbox
+    pub fn append(&mut self, message: ProcessMessage) -> Result<(), MessagingError> {
+        let msg_size = message.size();
+
+        if self.message_count.total() > 147730 {
+            return Err(MessagingError::TooManyMessages);
+        }
+
+        match msg_size {
+            TINY_MESSAGE_COUNT => {
+                if self.message_count.tiny < TINY_MESSAGE_COUNT {
+                    self.messages.push(message);
+                    self.message_count.tiny += 1;
+                    Ok(())
+                } else {
+                    Err(MessagingError::TooManyMessages)
+                }
+            }
+            SMALL_MESSAGE_COUNT => {
+                if self.message_count.small < SMALL_MESSAGE_COUNT {
+                    self.messages.push(message);
+                    self.message_count.small += 1;
+                    Ok(())
+                } else {
+                    Err(MessagingError::TooManyMessages)
+                }
+            }
+            MEDIUM_MESSAGE_COUNT => {
+                if self.message_count.medium < MEDIUM_MESSAGE_COUNT {
+                    self.messages.push(message);
+                    self.message_count.medium += 1;
+                    Ok(())
+                } else {
+                    Err(MessagingError::TooManyMessages)
+                }
+            }
+            LARGE_MESSAGE_COUNT => {
+                if self.message_count.large < LARGE_MESSAGE_COUNT {
+                    self.messages.push(message);
+                    self.message_count.large += 1;
+                    Ok(())
+                } else {
+                    Err(MessagingError::TooManyMessages)
+                }
+            }
+            HUGE_MESSAGE_COUNT => {
+                if self.message_count.huge < HUGE_MESSAGE_COUNT {
+                    self.messages.push(message);
+                    self.message_count.huge += 1;
+                    Ok(())
+                } else {
+                    return Err(MessagingError::TooManyMessages);
+                }
+            }
+            _ => Err(MessagingError::MessageTooLarge),
+        }
+    }
+}
+
+/// A proper struct to list the number of messages in the mailbox
+pub struct MessageCount {
+    /// The number of tiny messages in the mailbox
+    pub tiny: usize,
+    /// The number of small messages in the mailbox
+    pub small: usize,
+    /// The number of medium messages in the mailbox
+    pub medium: usize,
+    /// The number of large messages in the mailbox
+    pub large: usize,
+    /// The number of huge messages in the mailbox
+    pub huge: usize,
+}
+
+impl MessageCount {
+    /// Return the total number of messages in the mailbox
+    pub fn total(&self) -> usize {
+        self.tiny + self.small + self.medium + self.large + self.huge
+    }
+}
+
+impl Default for MessageCount {
+    fn default() -> Self {
+        MessageCount {
+            tiny: 0,
+            small: 0,
+            medium: 0,
+            large: 0,
+            huge: 0,
+        }
+    }
+}