You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: memop.rs
    path of file: ./repos/tock/kernel/src
    
    the code of the file until where you have to start completion: // Licensed under the Apache License, Version 2.0 or the MIT License.
// SPDX-License-Identifier: Apache-2.0 OR MIT
// Copyright Tock Contributors 2022.

//! Implementation of the MEMOP family of syscalls.

use crate::process::Process;
use crate::syscall::SyscallReturn;
use crate::ErrorCode;

/// Handle the `memop` syscall.
///
/// ### `memop_num`
///
/// - `0`: BRK. Change the location of the program break and return a
///   SyscallReturn.
/// - `1`: SBRK. Change the location of the program break and return the
///   previous break address.
/// - `2`: Get the address of the start of the application's RAM allocation.
/// - `3`: Get the address pointing to the first address after the end of the
///   application's RAM allocation.
/// - `4`: Get the addr
    
pub(crate) fn memop(process: &dyn Process, op_type: usize, r1: usize) -> SyscallReturn {
    match op_type {
        // Op Type 0: BRK
        0 => process
            .brk(r1 as *const u8)
            .map(|_| SyscallReturn::Success)
            .unwrap_or(SyscallReturn::Failure(ErrorCode::NOMEM)),

        // Op Type 1: SBRK
        1 => process
            .sbrk(r1 as isize)
            .map(|addr| SyscallReturn::SuccessU32(addr as u32))
            .unwrap_or(SyscallReturn::Failure(ErrorCode::NOMEM)),

        // Op Type 2: Process memory start
        2 => SyscallReturn::SuccessU32(process.get_addresses().sram_start as u32),

        // Op Type 3: Process memory end
        3 => SyscallReturn::SuccessU32(process.get_addresses().sram_end as u32),

        // Op Type 4: Process flash start
        4 => SyscallReturn::SuccessU32(process.get_addresses().flash_start as u32),

        // Op Type 5: Process flash end
        5 => SyscallReturn::SuccessU32(process.get_addresses().flash_end as u32),

        // Op Type 6: Grant region begin
        6 => SyscallReturn::SuccessU32(process.get_addresses().sram_grant_start as u32),

        // Op Type 7: Number of defined writeable regions in the TBF header.
        7 => SyscallReturn::SuccessU32(process.number_writeable_flash_regions() as u32),

        // Op Type 8: The start address of the writeable region indexed by r1.
        8 => {
            let flash_start = process.get_addresses().flash_start as u32;
            let (offset, size) = process.get_writeable_flash_region(r1);
            if size == 0 {
                SyscallReturn::Failure(ErrorCode::FAIL)
            } else {
                SyscallReturn::SuccessU32(flash_start + offset)
            }
        }

        // Op Type 9: The end address of the writeable region indexed by r1.
        // Returns (void*) -1 on failure, meaning the selected writeable region
        // does not exist.
        9 => {
            let flash_start = process.get_addresses().flash_start as u32;
            let (offset, size) = process.get_writeable_flash_region(r1);
            if size == 0 {
                SyscallReturn::Failure(ErrorCode::FAIL)
            } else {
                SyscallReturn::SuccessU32(flash_start + offset + size)
            }
        }

        // Op Type 10: Specify where the start of the app stack is.
        10 => {
            process.update_stack_start_pointer(r1 as *const u8);
            SyscallReturn::Success
        }

        // Op Type 11: Specify where the start of the app heap is.
        11 => {
            process.update_heap_start_pointer(r1 as *const u8);
            SyscallReturn::Success
        }

        _ => SyscallReturn::Failure(ErrorCode::NOSUPPORT),
    }
}