feature: implement block and fields as Struct implementing (Try)From trait

crates/sesam-vitale/src/ssv_memory.rs

@@ -4,25 +4,24 @@
 
 // TODO : Est-ce qu'on pourrait/devrait définir un type custom pour représenter les tableaux de bytes ?
 
+use std::convert::TryFrom;
+
 #[derive(PartialEq, Debug)]
-pub struct ElementSize {
+struct ElementSize {
     pub size: usize,
     pub pad: usize,
 }
 
-#[derive(PartialEq, Debug)]
+impl TryFrom<&[u8]> for ElementSize {
-pub enum MemoryParsingError<'a> {
+    type Error = &'static str;
-    MemoryIsEmpty(&'a str),
-    MemoryIsNotValid(&'a str),
-}
 
-pub fn read_element_size(bytes: &[u8]) -> Result<ElementSize, MemoryParsingError> {
+    fn try_from(bytes: &[u8]) -> Result<Self, Self::Error> {
             /* Longueur:
         *   - si le bit de poids fort du premier octet est à 0, la longueur est codée sur un octet
         *   - si le bit de poids fort du premier octet est à 1, les 7 bits de poids faible codent le nombre d'octets utilisés pour coder la longueur
         */
         if bytes.len() == 0 {
-        return Err(MemoryParsingError::MemoryIsEmpty("Empty bytes input"));
+            return Err("Empty bytes input");
         }
 
         let mut element_size = ElementSize { size: 0, pad: 1 };
@@ -34,13 +33,9 @@ pub fn read_element_size(bytes: &[u8]) -> Result<ElementSize, MemoryParsingError
             // N are the 7 lower bits of the first byte
             let size_bytes_len = (bytes[0] & 0b0111_1111) as usize;
             if size_bytes_len > bytes.len() - 1 {
-            return Err(MemoryParsingError::MemoryIsNotValid(
+                return Err("Invalid memory: not enough bytes to read the size");
-                "Invalid memory: not enough bytes to read the size",
-            ));
             } else if size_bytes_len > 4 {
-            return Err(MemoryParsingError::MemoryIsNotValid(
+                return Err("Invalid memory: size is too big");
-                "Invalid memory: size is too big",
-            ));
             }
             let size_bytes = &bytes[1..1 + size_bytes_len];
 
@@ -53,92 +48,134 @@ pub fn read_element_size(bytes: &[u8]) -> Result<ElementSize, MemoryParsingError
         }
         Ok(element_size)
     }
-
-pub struct Element {
-    pub pad: usize,
-    pub contenu: Vec<u8>,
 }
 
-pub fn read_element(bytes: &[u8]) -> Element {
+#[derive(Debug)]
-    let ElementSize { size, pad } = read_element_size(bytes).unwrap();
+pub struct Block<'a> {
-    let contenu = bytes[pad..pad+size].to_vec();
+    pub id: u16,
-    Element {
+    pub size: usize,
-        pad: pad+size,
+    pub content: Vec<Field<'a>>,
-        contenu,
 }
+
+impl<'a> From<&'a [u8]> for Block<'a> {
+    fn from(bytes: &'a [u8]) -> Self {
+        let mut offset = 0;
+        let id = u16::from_be_bytes(bytes[..2].try_into().unwrap());
+        offset += 2;
+        let ElementSize { size: block_size, pad } = bytes[2..].try_into().unwrap();
+        offset += pad;
+        let raw_content = &bytes[offset..];
+        let mut field_offset = 0;
+        // While there is still content to read, parse Fields
+        let mut content = Vec::new();
+        while field_offset < block_size {
+            let field: Field<'a> = raw_content[field_offset..].into();
+            field_offset += field.size;
+            content.push(field);
+        }
+        Block {
+            id,
+            size: offset + block_size,
+            content,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Field<'a> {
+    pub size: usize,
+    pub content: &'a [u8],
+}
+
+impl<'a> From<&'a [u8]> for Field<'a> {
+    fn from(bytes: &'a [u8]) -> Self {
+        let ElementSize { size, pad } = bytes.try_into().unwrap();
+        let contenu = &bytes[pad..pad+size];
+        Field {
+            size: pad+size,
+            content: contenu,
+        }
+    }
+}
+
+pub fn decode_ssv_memory(bytes: &[u8], size: usize) -> Vec<Block> {
+    let mut blocks: Vec<Block> = Vec::new();
+    let mut offset = 0;
+    while offset < size {
+        let block: Block = bytes[offset..].into();
+        offset += block.size;
+        blocks.push(block);
+    }
+    blocks
 }
 
 #[cfg(test)]
-mod test_read_element_size {
+mod test_element_size {
     use super::*;
 
     #[test]
     fn short_size() {
-        let bytes = [0b_0000_0001_u8];
+        let bytes: &[u8] = &[0b_0000_0001_u8];
-        let element_size = read_element_size(&bytes).unwrap();
+        let element_size: ElementSize = bytes.try_into().unwrap();
         assert_eq!(element_size.size, 1);
         assert_eq!(element_size.pad, 1);
 
-        let bytes = [0b_0100_0000_u8];
+        let bytes: &[u8] = &[0b_0100_0000_u8];
-        let element_size = read_element_size(&bytes).unwrap();
+        let element_size: ElementSize = bytes.try_into().unwrap();
         assert_eq!(element_size.size, 64);
         assert_eq!(element_size.pad, 1);
     }
 
     #[test]
     fn long_size() {
-        let bytes = [0b_1000_0010_u8, 0b_0000_0001_u8, 0b_0100_0000_u8];
+        let bytes: &[u8] = &[0b_1000_0010_u8, 0b_0000_0001_u8, 0b_0100_0000_u8];
-        let element_size = read_element_size(&bytes).unwrap();
+        let element_size: ElementSize = bytes.try_into().unwrap();
         assert_eq!(element_size.size, 320);
         assert_eq!(element_size.pad, 3);
     }
 
     #[test]
     fn null_size() {
-        let bytes = [];
+        let bytes: &[u8] = &[];
-        let toto = "toto";
+        let result: Result<ElementSize, &str> = bytes.try_into();
-        // Expect an error
         assert_eq!(
-            read_element_size(&bytes),
+            result,
-            Err(MemoryParsingError::MemoryIsEmpty("Empty bytes input")),
+            Err("Empty bytes input"),
         );
     }
 
     #[test]
     fn invalid_memory() {
-        let bytes = [0b_1000_0001_u8];
+        let bytes: &[u8] = &[0b_1000_0001_u8];
+        let result: Result<ElementSize, &str> = bytes.try_into();
         assert_eq!(
-            read_element_size(&bytes),
+            result,
-            Err(MemoryParsingError::MemoryIsNotValid(
+            Err("Invalid memory: not enough bytes to read the size"),
-                "Invalid memory: not enough bytes to read the size"
-            )),
         );
 
-        let bytes = [0b_1000_0010_u8, 1];
+        let bytes: &[u8] = &[0b_1000_0010_u8, 1];
+        let result: Result<ElementSize, &str> = bytes.try_into();
         assert_eq!(
-            read_element_size(&bytes),
+            result,
-            Err(MemoryParsingError::MemoryIsNotValid(
+            Err("Invalid memory: not enough bytes to read the size"),
-                "Invalid memory: not enough bytes to read the size"
-            )),
         );
 
-        let bytes = [0b_1000_0101_u8, 1, 1, 1, 1, 1];
+        let bytes: &[u8] = &[0b_1000_0101_u8, 1, 1, 1, 1, 1];
+        let result: Result<ElementSize, &str> = bytes.try_into();
         assert_eq!(
-            read_element_size(&bytes),
+            result,
-            Err(MemoryParsingError::MemoryIsNotValid(
+            Err("Invalid memory: size is too big"),
-                "Invalid memory: size is too big"
-            )),
         );
     }
 }
 
 #[cfg(test)]
-mod test_read_element {
+mod test_field {
     use super::*;
 
     #[test]
     fn short_size() {
-        let bytes = [51,
+        let bytes: &[u8] = &[51,
             1, 48, 1, 56, 11, 57, 57, 55, 48, 48,
             53, 50, 52, 49, 57, 52, 1, 52, 2, 50,
             50, 17, 80, 72, 65, 82, 77, 65, 67, 73,
@@ -146,20 +183,142 @@ mod test_read_element {
             70, 82, 65, 78, 67, 79, 73, 83, 69, 1,
             84,
         ];
-        let element = read_element(&bytes);
+        let element: Field = bytes.try_into().unwrap();
-        assert_eq!(element.pad, 52);
+        assert_eq!(element.size, 52);
-        assert_eq!(element.contenu[..5], [1, 48, 1, 56, 11]);
+        assert_eq!(element.content[..5], [1, 48, 1, 56, 11]);
     }
 
     #[test]
     fn long_size() {
-        let mut bytes = vec![0b_1000_0010_u8,
+        let mut bytes_vec = vec![0b_1000_0010_u8,
             0b_0000_0001_u8, 0b_0000_0000_u8, // size = 256
         ];
         // Add 256 bytes to the content
-        bytes.append(&mut vec![1; 256]);
+        bytes_vec.append(&mut vec![1; 256]);
-        let element = read_element(&bytes);
+        let bytes: &[u8] = &bytes_vec;
-        assert_eq!(element.pad, 259);
+        let element: Field = bytes.try_into().unwrap();
-        assert_eq!(element.contenu.len(), 256);
+        assert_eq!(element.size, 259);
+        assert_eq!(element.content.len(), 256);
+    }
+}
+
+#[cfg(test)]
+mod test_block {
+    use super::*;
+
+    #[test]
+    fn test_francoise_pharmacien0052419_partial_block_1() {
+        let bytes: &[u8] = &[
+            1, 48,
+            1, 56,
+            11, 57, 57, 55, 48, 48, 53, 50, 52, 49, 57, 52,
+        ];
+        
+        let field1: Field = bytes.into();
+        assert_eq!(field1.size, 2);
+        assert_eq!(field1.content, &[48]);
+
+        let field2: Field = bytes[field1.size..].into();
+        assert_eq!(field2.size, 2);
+        assert_eq!(field2.content, &[56]);
+
+        let field3: Field = bytes[field1.size + field2.size..].into();
+        assert_eq!(field3.size, 12);
+        assert_eq!(field3.content, &[57, 57, 55, 48, 48, 53, 50, 52, 49, 57, 52]);
+    }
+
+    #[test]
+    fn test_francoise_pharmacien0052419() {
+        let bytes: &[u8] = &[
+        0, 1, 51, // 3
+            1, 48, // 2
+            1, 56, // 2
+            11, 57, 57, 55, 48, 48, 53, 50, 52, 49, 57, 52, // 12
+            1, 52, // 2
+            2, 50, 50, // 3
+            17, 80, 72, 65, 82, 77, 65, 67, 73, 69, 78, 48, 48, 53, 50, 52, 49, 57, // 18
+            9, 70, 82, 65, 78, 67, 79, 73, 83, 69, // 10
+            1, 84, // 2
+        // total: 54
+            
+        0, 2, 83,
+            1, 1,
+            1, 48,
+            1, 49,
+            2, 56, 54,
+            1, 49,
+            9, 48, 66, 48, 50, 50, 49, 57, 53, 56,
+            1, 56,
+            24, 80, 72, 65, 82, 77, 65, 67, 73, 69, 32, 68, 85, 32, 67, 69, 78, 84, 82, 69, 50, 50, 49, 57, 53,
+            8, 48, 48, 50, 48, 50, 52, 49, 57,
+            1, 56,
+            0,
+            1, 48,
+            1, 49,
+            2, 53, 48,
+            2, 49, 48,
+            2, 48, 48,
+            1, 48,
+            1, 48,
+            1, 48,
+            1, 49,
+            1, 49,
+        ];
+        
+        let first_block: Block = bytes.into();
+        assert_eq!(first_block.id, 1);
+        assert_eq!(first_block.size, 54);
+        assert_eq!(first_block.content.len(), 8);
+
+        let second_block: Block = bytes[first_block.size..].into();
+        assert_eq!(second_block.id, 2);
+        assert_eq!(second_block.size, 86);
+        assert_eq!(second_block.content.len(), 21);
+    }
+}
+
+#[cfg(test)]
+mod test_decode_ssv_memory {
+    use super::*;
+
+    #[test]
+    fn test_francoise_pharmacien0052419() {
+        let bytes: &[u8] = &[
+        0, 1, 51, // 3
+            1, 48, // 2
+            1, 56, // 2
+            11, 57, 57, 55, 48, 48, 53, 50, 52, 49, 57, 52, // 12
+            1, 52, // 2
+            2, 50, 50, // 3
+            17, 80, 72, 65, 82, 77, 65, 67, 73, 69, 78, 48, 48, 53, 50, 52, 49, 57, // 18
+            9, 70, 82, 65, 78, 67, 79, 73, 83, 69, // 10
+            1, 84, // 2
+        // total: 54
+            
+        0, 2, 83,
+            1, 1,
+            1, 48,
+            1, 49,
+            2, 56, 54,
+            1, 49,
+            9, 48, 66, 48, 50, 50, 49, 57, 53, 56,
+            1, 56,
+            24, 80, 72, 65, 82, 77, 65, 67, 73, 69, 32, 68, 85, 32, 67, 69, 78, 84, 82, 69, 50, 50, 49, 57, 53,
+            8, 48, 48, 50, 48, 50, 52, 49, 57,
+            1, 56,
+            0,
+            1, 48,
+            1, 49,
+            2, 53, 48,
+            2, 49, 48,
+            2, 48, 48,
+            1, 48,
+            1, 48,
+            1, 48,
+            1, 49,
+            1, 49,
+        ];
+        let blocks = decode_ssv_memory(&bytes, bytes.len());
+        assert_eq!(blocks.len(), 2);
     }
 }