language-servers/roc
1
0
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2025-09-28 22:34:45 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 6

Revise RocStr a bit

Browse source
This commit is contained in:
Richard Feldman 2020-11-29 22:20:16 -05:00
parent 214c338647
commit 19e5c1350e
1 changed files with 8 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

20
compiler/builtins/bitcode/src/str.zig
View file

@ -7,7 +7,7 @@ const expect = testing.expect;
extern fn malloc(size: usize) ?*u8;
extern fn free([*]u8) void;
const RocStr = struct {
const RocStr = extern struct {
str_bytes: ?[*]u8,
str_len: usize,
@ -119,14 +119,13 @@ const RocStr = struct {
return if (self.is_small_str()) small_len else big_len;
}
// Given a pointer to some memory of length (self.len() + 1) bytes,
// write this RocStr's contents into it as a nul-terminated C string.
// Given a pointer to some bytes, write the first (len) bytes of this
// RocStr's contents into it.
//
// This is useful so that (for example) we can write into an `alloca`
// if the C string only needs to live long enough to be passed as an
// argument to a C function - like the file path argument to `fopen`.
pub fn write_cstr(self: RocStr, dest: [*]u8) void {
const len: usize = self.len();
// One use for this function is writing into an `alloca` for a C string that
// only needs to live long enough to be passed as an argument to
// a C function - like the file path argument to `fopen`.
pub fn memcpy(self: RocStr, dest: [*]u8, len: usize) void {
const small_src = @ptrCast(*u8, self);
const big_src = self.str_bytes_ptr;
@ -135,12 +134,9 @@ const RocStr = struct {
// Since this conditional would be prone to branch misprediction,
// make sure it will compile to a cmov.
const src: [*]u8 = if (len < @sizeOf(RocStr)) small_src else big_src;
const src: [*]u8 = if (self.is_small_str()) small_src else big_src;
@memcpy(dest, src, len);
// C strings must end in 0.
dest[len + 1] = 0;
}
test "RocStr.eq: equal" {