Merge pull request #1049 from rtfeldman/map2

List.map2
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Richard Feldman 2021-03-05 22:55:12 -05:00 committed by GitHub
commit 1211fa93f7
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11 changed files with 230 additions and 2 deletions

View file

@ -153,6 +153,66 @@ pub fn listMapWithIndex(list: RocList, transform: Opaque, caller: Caller2, align
}
}
pub fn listMap2(list1: RocList, list2: RocList, transform: Opaque, caller: Caller2, alignment: usize, a_width: usize, b_width: usize, c_width: usize, dec_a: Dec, dec_b: Dec) callconv(.C) RocList {
const output_length = std.math.min(list1.len(), list2.len());
if (list1.bytes) |source_a| {
if (list2.bytes) |source_b| {
const output = RocList.allocate(std.heap.c_allocator, alignment, output_length, c_width);
const target_ptr = output.bytes orelse unreachable;
var i: usize = 0;
while (i < output_length) : (i += 1) {
const element_a = source_a + i * a_width;
const element_b = source_b + i * b_width;
const target = target_ptr + i * c_width;
caller(transform, element_a, element_b, target);
}
// if the lists don't have equal length, we must consume the remaining elements
// In this case we consume by (recursively) decrementing the elements
if (list1.len() > output_length) {
while (i < list1.len()) : (i += 1) {
const element_a = source_a + i * a_width;
dec_a(element_a);
}
} else if (list2.len() > output_length) {
while (i < list2.len()) : (i += 1) {
const element_b = source_b + i * b_width;
dec_b(element_b);
}
}
utils.decref(std.heap.c_allocator, alignment, list1.bytes, list1.len() * a_width);
utils.decref(std.heap.c_allocator, alignment, list2.bytes, list2.len() * b_width);
return output;
} else {
// consume list1 elements (we know there is at least one because the list1.bytes pointer is non-null
var i: usize = 0;
while (i < list1.len()) : (i += 1) {
const element_a = source_a + i * a_width;
dec_a(element_a);
}
utils.decref(std.heap.c_allocator, alignment, list1.bytes, list1.len() * a_width);
return RocList.empty();
}
} else {
// consume list2 elements (if any)
if (list2.bytes) |source_b| {
var i: usize = 0;
while (i < list2.len()) : (i += 1) {
const element_b = source_b + i * b_width;
dec_b(element_b);
}
utils.decref(std.heap.c_allocator, alignment, list2.bytes, list2.len() * b_width);
}
return RocList.empty();
}
}
pub fn listKeepIf(list: RocList, transform: Opaque, caller: Caller1, alignment: usize, element_width: usize, inc: Inc, dec: Dec) callconv(.C) RocList {
if (list.bytes) |source_ptr| {
const size = list.len();

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@ -7,6 +7,7 @@ const list = @import("list.zig");
comptime {
exportListFn(list.listMap, "map");
exportListFn(list.listMap2, "map2");
exportListFn(list.listMapWithIndex, "map_with_index");
exportListFn(list.listKeepIf, "keep_if");
exportListFn(list.listWalk, "walk");