Zig 0.17.0-dev (Split by item)

?

× Shortcut keys

?: Show these tips

S: Focus search field

Esc: Clear focus & close tips

U: Jump to source code

↑: Move up in search results

↓: Move down in search results

↵: Go to active search result

This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Public Function

remap

Doc Source

Public Function

std.mem.Allocator.remap

pub fn remap(self: Allocator, allocation: anytype, new_len: usize) ?Slice(AbsorbSentinel(@TypeOf(allocation)))

Request to modify the size of an allocation, allowing relocation.

A non-null return value indicates the resize was successful. The allocation may have same address, or may have been relocated. In either case, the allocation now has size of new_len. A null return value indicates that the resize would be equivalent to allocating new memory, copying the bytes from the old memory, and then freeing the old memory. In such case, it is more efficient for the caller to perform those operations.

allocation may be an empty slice, in which case null is returned, unless new_len is also 0, in which case allocation is returned.

new_len may be zero, in which case the allocation is freed.

If the allocation's elements' type is zero bytes sized, allocation.len is set to new_len.

Params

self: Allocator
allocation
new_len: usize

File

mem/Allocator.zig:358

pub fn remap(self: Allocator, allocation: anytype, new_len: usize) ?Slice(AbsorbSentinel(@TypeOf(allocation))) {
    const slice_info = @typeInfo(@TypeOf(allocation)).pointer;
    const T = if (slice_info.size != .slice) comptime T: {
        assert(slice_info.size == .one);
        break :T @typeInfo(slice_info.child).array.child;
    } else slice_info.child;

    if (new_len == 0) {
        self.free(allocation);
        return allocation[0..0];
    }
    if (allocation.len == 0) {
        return null;
    }
    if (@sizeOf(T) == 0) {
        var new_memory = allocation;
        new_memory.len = new_len;
        return new_memory;
    }
    const old_memory: []u8 = @ptrCast(@constCast(mem.absorbSentinel(allocation)));
    const new_len_bytes = math.mul(usize, @sizeOf(T), new_len) catch return null;
    const new_ptr = self.rawRemap(
        old_memory,
        .fromByteUnits(slice_info.attrs.@"align" orelse @alignOf(T)),
        new_len_bytes,
        @returnAddress(),
    ) orelse return null;
    return @ptrCast(@alignCast(new_ptr[0..new_len_bytes]));
}