authorgravatar for walt@waltermays.comWalter Mays <walt@waltermays.com> 2020-05-26 12:04:25-05:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2020-05-26 13:04:25-04:00
log19a04d8ebd4d671a7f461048555831a629243b49
tree508cc177f78b1b6c832d87df7adad4534b975a5d
parentcb6bc5bdb5a3ebc95b0ee5fa414c4a2d4449e172
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

Add `writeToSlice` method to SegmentedList. (#5405)

1 files changed, 53 insertions(+), 4 deletions(-)

lib/std/segmented_list.zig+53-4
...@@ -213,6 +213,34 @@ pub fn SegmentedList(comptime T: type, comptime prealloc_item_count: usize) type...@@ -213,6 +213,34 @@ pub fn SegmentedList(comptime T: type, comptime prealloc_item_count: usize) type
213 self.len = new_len;213 self.len = new_len;
214 }214 }
215215
216 pub fn writeToSlice(self: *Self, dest: []T, start: usize) void {
217 const end = start + dest.len;
218 assert(end <= self.len);
219
220 var i = start;
221 if (end <= prealloc_item_count) {
222 std.mem.copy(T, dest[i - start ..], self.prealloc_segment[i..end]);
223 return;
224 } else if (i < prealloc_item_count) {
225 std.mem.copy(T, dest[i - start ..], self.prealloc_segment[i..]);
226 i = prealloc_item_count;
227 }
228
229 while (i < end) {
230 const shelf_index = shelfIndex(i);
231 const copy_start = boxIndex(i, shelf_index);
232 const copy_end = std.math.min(shelfSize(shelf_index), copy_start + end - i);
233
234 std.mem.copy(
235 T,
236 dest[i - start ..],
237 self.dynamic_segments[shelf_index][copy_start..copy_end],
238 );
239
240 i += (copy_end - copy_start);
241 }
242 }
243
216 pub fn uncheckedAt(self: var, index: usize) AtType(@TypeOf(self)) {244 pub fn uncheckedAt(self: var, index: usize) AtType(@TypeOf(self)) {
217 if (index < prealloc_item_count) {245 if (index < prealloc_item_count) {
218 return &self.prealloc_segment[index];246 return &self.prealloc_segment[index];
...@@ -395,10 +423,31 @@ fn testSegmentedList(comptime prealloc: usize, allocator: *Allocator) !void {...@@ -395,10 +423,31 @@ fn testSegmentedList(comptime prealloc: usize, allocator: *Allocator) !void {
395 try list.pushMany(&[_]i32{});423 try list.pushMany(&[_]i32{});
396 testing.expect(list.len == 99);424 testing.expect(list.len == 99);
397425
398 var i: i32 = 99;426 {
399 while (list.pop()) |item| : (i -= 1) {427 var i: i32 = 99;
400 testing.expect(item == i);428 while (list.pop()) |item| : (i -= 1) {
401 list.shrinkCapacity(list.len);429 testing.expect(item == i);
430 list.shrinkCapacity(list.len);
431 }
432 }
433
434 {
435 var control: [100]i32 = undefined;
436 var dest: [100]i32 = undefined;
437
438 var i: i32 = 0;
439 while (i < 100) : (i += 1) {
440 try list.push(i + 1);
441 control[@intCast(usize, i)] = i + 1;
442 }
443
444 std.mem.set(i32, dest[0..], 0);
445 list.writeToSlice(dest[0..], 0);
446 testing.expect(std.mem.eql(i32, control[0..], dest[0..]));
447
448 std.mem.set(i32, dest[0..], 0);
449 list.writeToSlice(dest[50..], 50);
450 testing.expect(std.mem.eql(i32, control[50..], dest[50..]));
402 }451 }
403452
404 try list.setCapacity(0);453 try list.setCapacity(0);