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context.rs
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context.rs
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use core::marker::PhantomData;
use ffi;
use types::{c_uint, c_void};
use Error;
use Secp256k1;
#[cfg(feature = "std")]
pub use self::std_only::*;
/// A type that represents the type with the biggest alignment we can get in rust.
/// Trying to match what `malloc` does in C, this should be aligned enough to contain pointers too.
/// This type can have different size/alignment depending on the architecture.
#[cfg(any(target_pointer_width = "32", target_pointer_width = "16", target_pointer_width = "8"))]
pub type AlignType = u64;
/// A type that represents the type with the biggest alignment we can get in rust.
/// Trying to match what `malloc` does in C, this should be aligned enough to contain pointers too.
/// This type can have different size/alignment depending on the architecture.
#[cfg(not(any(target_pointer_width = "32", target_pointer_width = "16", target_pointer_width = "8")))]
pub type AlignType = usize;
/// A trait for all kinds of Context's that Lets you define the exact flags and a function to deallocate memory.
/// * DO NOT * implement it for your own types.
pub unsafe trait Context {
/// Flags for the ffi.
const FLAGS: c_uint;
/// A constant description of the context.
const DESCRIPTION: &'static str;
/// A function to deallocate the memory when the context is dropped.
fn deallocate(ptr: *mut [AlignType]);
}
/// Marker trait for indicating that an instance of `Secp256k1` can be used for signing.
pub trait Signing: Context {}
/// Marker trait for indicating that an instance of `Secp256k1` can be used for verification.
pub trait Verification: Context {}
/// Represents the set of capabilities needed for signing with a user preallocated memory.
pub struct SignOnlyPreallocated<'buf> {
phantom: PhantomData<&'buf ()>,
}
/// Represents the set of capabilities needed for verification with a user preallocated memory.
pub struct VerifyOnlyPreallocated<'buf> {
phantom: PhantomData<&'buf ()>,
}
/// Represents the set of all capabilities with a user preallocated memory.
pub struct AllPreallocated<'buf> {
phantom: PhantomData<&'buf ()>,
}
#[cfg(feature = "std")]
mod std_only {
use super::*;
/// Represents the set of capabilities needed for signing.
pub enum SignOnly {}
/// Represents the set of capabilities needed for verification.
pub enum VerifyOnly {}
/// Represents the set of all capabilities.
pub enum All {}
impl Signing for SignOnly {}
impl Signing for All {}
impl Verification for VerifyOnly {}
impl Verification for All {}
unsafe impl Context for SignOnly {
const FLAGS: c_uint = ffi::SECP256K1_START_SIGN;
const DESCRIPTION: &'static str = "signing only";
fn deallocate(ptr: *mut [AlignType]) {
let _ = unsafe { Box::from_raw(ptr) };
}
}
unsafe impl Context for VerifyOnly {
const FLAGS: c_uint = ffi::SECP256K1_START_VERIFY;
const DESCRIPTION: &'static str = "verification only";
fn deallocate(ptr: *mut [AlignType]) {
let _ = unsafe { Box::from_raw(ptr) };
}
}
unsafe impl Context for All {
const FLAGS: c_uint = VerifyOnly::FLAGS | SignOnly::FLAGS;
const DESCRIPTION: &'static str = "all capabilities";
fn deallocate(ptr: *mut [AlignType]) {
let _ = unsafe { Box::from_raw(ptr) };
}
}
impl<C: Context> Secp256k1<C> {
/// Lets you create a context in a generic manner(sign/verify/all)
pub fn gen_new() -> Secp256k1<C> {
let buf = vec![0 as AlignType; Self::preallocate_size_gen()].into_boxed_slice();
let ptr = Box::into_raw(buf);
Secp256k1 {
ctx: unsafe { ffi::secp256k1_context_preallocated_create(ptr as *mut c_void, C::FLAGS) },
phantom: PhantomData,
buf: ptr,
}
}
}
impl Secp256k1<All> {
/// Creates a new Secp256k1 context with all capabilities
pub fn new() -> Secp256k1<All> {
Secp256k1::gen_new()
}
}
impl Secp256k1<SignOnly> {
/// Creates a new Secp256k1 context that can only be used for signing
pub fn signing_only() -> Secp256k1<SignOnly> {
Secp256k1::gen_new()
}
}
impl Secp256k1<VerifyOnly> {
/// Creates a new Secp256k1 context that can only be used for verification
pub fn verification_only() -> Secp256k1<VerifyOnly> {
Secp256k1::gen_new()
}
}
impl Default for Secp256k1<All> {
fn default() -> Self {
Self::new()
}
}
impl<C: Context> Clone for Secp256k1<C> {
fn clone(&self) -> Secp256k1<C> {
let clone_size = unsafe {ffi::secp256k1_context_preallocated_clone_size(self.ctx)};
let ptr_buf = Box::into_raw(vec![0 as AlignType; clone_size].into_boxed_slice());
Secp256k1 {
ctx: unsafe { ffi::secp256k1_context_preallocated_clone(self.ctx, ptr_buf as *mut c_void) },
phantom: PhantomData,
buf: ptr_buf,
}
}
}
}
impl<'buf> Signing for SignOnlyPreallocated<'buf> {}
impl<'buf> Signing for AllPreallocated<'buf> {}
impl<'buf> Verification for VerifyOnlyPreallocated<'buf> {}
impl<'buf> Verification for AllPreallocated<'buf> {}
unsafe impl<'buf> Context for SignOnlyPreallocated<'buf> {
const FLAGS: c_uint = ffi::SECP256K1_START_SIGN;
const DESCRIPTION: &'static str = "signing only";
fn deallocate(_ptr: *mut [AlignType]) {
// Allocated by the user
}
}
unsafe impl<'buf> Context for VerifyOnlyPreallocated<'buf> {
const FLAGS: c_uint = ffi::SECP256K1_START_VERIFY;
const DESCRIPTION: &'static str = "verification only";
fn deallocate(_ptr: *mut [AlignType]) {
// Allocated by the user
}
}
unsafe impl<'buf> Context for AllPreallocated<'buf> {
const FLAGS: c_uint = SignOnlyPreallocated::FLAGS | VerifyOnlyPreallocated::FLAGS;
const DESCRIPTION: &'static str = "all capabilities";
fn deallocate(_ptr: *mut [AlignType]) {
// Allocated by the user
}
}
impl<'buf, C: Context + 'buf> Secp256k1<C> {
/// Lets you create a context with preallocated buffer in a generic manner(sign/verify/all)
pub fn preallocated_gen_new(buf: &'buf mut [AlignType]) -> Result<Secp256k1<C>, Error> {
if buf.len() < Self::preallocate_size_gen() {
return Err(Error::NotEnoughMemory);
}
Ok(Secp256k1 {
ctx: unsafe {
ffi::secp256k1_context_preallocated_create(
buf.as_mut_ptr() as *mut c_void,
C::FLAGS)
},
phantom: PhantomData,
buf: buf as *mut [AlignType],
})
}
}
impl<'buf> Secp256k1<AllPreallocated<'buf>> {
/// Creates a new Secp256k1 context with all capabilities
pub fn preallocated_new(buf: &'buf mut [AlignType]) -> Result<Secp256k1<AllPreallocated<'buf>>, Error> {
Secp256k1::preallocated_gen_new(buf)
}
/// Returns the required memory for a preallocated context buffer in a generic manner(sign/verify/all)
///
/// Notice that the memory returned is in [AlignType](type.AlignType.html)
///
/// ## Examples
/// ```rust
/// # use secp256k1::*;
/// let buf_size = Secp256k1::preallocate_size();
/// let mut buf = vec![0; buf_size];
/// let secp = Secp256k1::preallocated_new(&mut buf).unwrap();
///
/// ```
pub fn preallocate_size() -> usize {
Self::preallocate_size_gen()
}
}
impl<'buf> Secp256k1<SignOnlyPreallocated<'buf>> {
/// Creates a new Secp256k1 context that can only be used for signing
pub fn preallocated_signing_only(buf: &'buf mut [AlignType]) -> Result<Secp256k1<SignOnlyPreallocated<'buf>>, Error> {
Secp256k1::preallocated_gen_new(buf)
}
/// Returns the required memory for a preallocated context buffer in a generic manner(sign/verify/all)
///
/// Notice that the memory returned is in [AlignType](type.AlignType.html)
///
/// ## Examples
/// ```rust
/// # use secp256k1::*;
/// let buf_size = Secp256k1::preallocate_signing_size();
/// let mut buf = vec![0; buf_size];
/// let secp = Secp256k1::preallocated_signing_only(&mut buf).unwrap();
///
/// ```
#[inline]
pub fn preallocate_signing_size() -> usize {
Self::preallocate_size_gen()
}
}
impl<'buf> Secp256k1<VerifyOnlyPreallocated<'buf>> {
/// Creates a new Secp256k1 context that can only be used for verification
pub fn preallocated_verification_only(buf: &'buf mut [AlignType]) -> Result<Secp256k1<VerifyOnlyPreallocated<'buf>>, Error> {
Secp256k1::preallocated_gen_new(buf)
}
/// Returns the required memory for a preallocated context buffer in a generic manner(sign/verify/all)
///
/// Notice that the memory returned is in [AlignType](type.AlignType.html)
///
/// ## Examples
/// ```rust
/// # use secp256k1::*;
/// let buf_size = Secp256k1::preallocate_verification_size();
/// let mut buf = vec![0; buf_size];
/// let secp = Secp256k1::preallocated_verification_only(&mut buf).unwrap();
///
/// ```
#[inline]
pub fn preallocate_verification_size() -> usize {
Self::preallocate_size_gen()
}
}