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Fix llseek behavior

master
LemonBoy 2019-09-25 16:38:25 +02:00 committed by Andrew Kelley
parent 48c9e17aa1
commit 3907e3b675
2 changed files with 31 additions and 3 deletions
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24
std/io/test.zig
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@ -609,3 +609,27 @@ test "c out stream" {
const out_stream = &io.COutStream.init(out_file).stream;
try out_stream.print("hi: {}\n", i32(123));
}
test "File seek ops" {
const tmp_file_name = "temp_test_file.txt";
var file = try File.openWrite(tmp_file_name);
defer {
file.close();
fs.deleteFile(tmp_file_name) catch {};
}
try file.write([_]u8{0x55} ** 8192);
// Seek to the end
try file.seekFromEnd(0);
std.testing.expect((try file.getPos()) == try file.getEndPos());
// Negative delta
try file.seekBy(-4096);
std.testing.expect((try file.getPos()) == 4096);
// Positive delta
try file.seekBy(10);
std.testing.expect((try file.getPos()) == 4106);
// Absolute position
try file.seekTo(1234);
std.testing.expect((try file.getPos()) == 1234);
}

10
std/os.zig
View File

@ -2243,7 +2243,8 @@ pub const SeekError = error{
/// Repositions read/write file offset relative to the beginning.
pub fn lseek_SET(fd: fd_t, offset: u64) SeekError!void {
if (linux.is_the_target and !builtin.link_libc and @sizeOf(usize) == 4) {
switch (errno(system.llseek(fd, offset, null, SEEK_SET))) {
var result: u64 = undefined;
switch (errno(system.llseek(fd, offset, &result, SEEK_SET))) {
0 => return,
EBADF => unreachable, // always a race condition
EINVAL => return error.Unseekable,
@ -2271,7 +2272,8 @@ pub fn lseek_SET(fd: fd_t, offset: u64) SeekError!void {
/// Repositions read/write file offset relative to the current offset.
pub fn lseek_CUR(fd: fd_t, offset: i64) SeekError!void {
if (linux.is_the_target and !builtin.link_libc and @sizeOf(usize) == 4) {
switch (errno(system.llseek(fd, @bitCast(u64, offset), null, SEEK_CUR))) {
var result: u64 = undefined;
switch (errno(system.llseek(fd, @bitCast(u64, offset), &result, SEEK_CUR))) {
0 => return,
EBADF => unreachable, // always a race condition
EINVAL => return error.Unseekable,
@ -2298,7 +2300,9 @@ pub fn lseek_CUR(fd: fd_t, offset: i64) SeekError!void {
/// Repositions read/write file offset relative to the end.
pub fn lseek_END(fd: fd_t, offset: i64) SeekError!void {
if (linux.is_the_target and !builtin.link_libc and @sizeOf(usize) == 4) {
switch (errno(system.llseek(fd, @bitCast(u64, offset), null, SEEK_END))) {
var result: u64 = undefined;
switch (errno(system.llseek(fd, @bitCast(u64, offset), &result, SEEK_END))) {
0 => return,
EBADF => unreachable, // always a race condition
EINVAL => return error.Unseekable,
EOVERFLOW => return error.Unseekable,