#54 Ported new string algorithm to virt_mem

memflow/src/mem/virt_mem.rs

@@ -218,31 +218,50 @@ where
         Ok(String::from_utf8_lossy(&buf).to_string())
     }
 
-    /// Reads a variable length string with a length of up to 4kb from the target.
+    /// Reads a variable length string with a length of up to specified amount from the target.
+    ///
+    /// # Arguments
+    ///
+    /// * `addr` - target address to read from
+    /// * `n` - maximum number of bytes to read
     ///
     /// # Remarks:
     ///
     /// The string must be null-terminated.
     /// If no null terminator is found the this function will return an error.
     ///
     /// For reading fixed-size char arrays the [`virt_read_char_array`] should be used.
-    fn virt_read_char_string(&mut self, addr: Address) -> PartialResult<String> {
+    fn virt_read_char_string_n(&mut self, addr: Address, n: usize) -> Result<String> {
         let mut buf = vec![0; 32];
+
+        let mut last_n = 0;
+
         loop {
-            self.virt_read_raw_into(addr, &mut buf).data_part()?;
+            let (_, right) = buf.split_at_mut(last_n);
+
+            self.virt_read_raw_into(addr, right)?;
             if let Some((n, _)) = buf.iter().enumerate().find(|(_, c)| **c == 0_u8) {
-                buf.truncate(n);
+                buf.truncate(last_n + n);
                 return Ok(String::from_utf8_lossy(&buf).to_string());
             }
-            if buf.len() * 2 > 4096 {
+            if buf.len() >= n {
                 break;
             }
-            buf.extend(vec![0; buf.len()]);
+            last_n = buf.len();
+
+            buf.extend((0..buf.len()).map(|_| 0));
         }
-        Err(PartialError::Error(Error(
-            ErrorOrigin::VirtualMemory,
-            ErrorKind::OutOfBounds,
-        )))
+
+        Err(Error(ErrorOrigin::VirtualMemory, ErrorKind::OutOfBounds))
+    }
+
+    /// Reads a variable length string with up to 4kb length from the target.
+    ///
+    /// # Arguments
+    ///
+    /// * `addr` - target address to read from
+    fn virt_read_char_string(&mut self, addr: Address) -> Result<String> {
+        self.virt_read_char_string_n(addr, 4096)
     }
 
     fn virt_batcher(&mut self) -> VirtualMemoryBatcher<Self>