authorgravatar for drsingh2518@icloud.comdevins2518 <drsingh2518@icloud.com> 2022-07-23 06:22:35-05:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2022-07-23 14:22:35+03:00
log5647a73fea7ecc9e1ee190362ef47f402eb95dff
treefd0291f37c3f48b89d523149e7df6ec695cba057
parent9555b84ab43caeaaa85e7f25424c3ba731075142
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

std.mem.Allocator: add alignedCreate

1 files changed, 58 insertions(+), 0 deletions(-)

lib/std/mem/Allocator.zig+58
...@@ -185,6 +185,64 @@ pub fn create(self: Allocator, comptime T: type) Error!*T {...@@ -185,6 +185,64 @@ pub fn create(self: Allocator, comptime T: type) Error!*T {
185 return &slice[0];185 return &slice[0];
186}186}
187187
188/// Returns an aligned pointer to undefined memory.
189/// Call `destroy` with the result to free the memory.
190pub fn alignedCreate(
191 self: Allocator,
192 comptime T: type,
193 // null means naturally aligned
194 comptime alignment: ?u29,
195) Error!*align(alignment orelse @alignOf(T)) T {
196 if (@sizeOf(T) == 0) return @as(*T, undefined);
197 const slice = try self.allocAdvancedWithRetAddr(T, alignment, 1, .exact, @returnAddress());
198 return &slice[0];
199}
200
201test "create" {
202 // Non-zero type, greater alignment
203 {
204 const x = try std.testing.allocator.alignedCreate(u8, @alignOf(u32));
205 defer std.testing.allocator.destroy(x);
206
207 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(u32));
208 }
209 // Non-zero type, null alignment
210 {
211 const x = try std.testing.allocator.alignedCreate(u8, null);
212 defer std.testing.allocator.destroy(x);
213
214 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(u8));
215 }
216 // Non-zero type, lesser alignment
217 {
218 const x = try std.testing.allocator.alignedCreate(u32, @alignOf(u5));
219 defer std.testing.allocator.destroy(x);
220
221 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(u5));
222 }
223 // Zero type, greater alignment
224 {
225 const x = try std.testing.allocator.alignedCreate([0]u8, @alignOf(u32));
226 defer std.testing.allocator.destroy(x);
227
228 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(void));
229 }
230 // Zero type, null alignment
231 {
232 const x = try std.testing.allocator.alignedCreate([0]u8, null);
233 defer std.testing.allocator.destroy(x);
234
235 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(void));
236 }
237 // Zero alignment, lesser alignment
238 {
239 const x = try std.testing.allocator.alignedCreate([0]u8, @alignOf(u5));
240 defer std.testing.allocator.destroy(x);
241
242 assert(@typeInfo(@TypeOf(x)).Pointer.alignment == @alignOf(void));
243 }
244}
245
188/// `ptr` should be the return value of `create`, or otherwise246/// `ptr` should be the return value of `create`, or otherwise
189/// have the same address and alignment property.247/// have the same address and alignment property.
190pub fn destroy(self: Allocator, ptr: anytype) void {248pub fn destroy(self: Allocator, ptr: anytype) void {