From 5eb2a8f7bdda44354c27a2f8cb5267524ba09135 Mon Sep 17 00:00:00 2001
From: lmiskiew <lukasz.miskiewicz20@gmail.com>
Date: Thu, 28 Feb 2019 08:23:11 +0000
Subject: [PATCH] Implement swab
---
src/header/unistd/mod.rs | 15 +++++++--
tests/Makefile | 1 +
tests/expected/unistd/swab.stderr | 0
tests/expected/unistd/swab.stdout | 0
tests/unistd/swab.c | 51 +++++++++++++++++++++++++++++++
5 files changed, 65 insertions(+), 2 deletions(-)
create mode 100644 tests/expected/unistd/swab.stderr
create mode 100644 tests/expected/unistd/swab.stdout
create mode 100644 tests/unistd/swab.c
diff --git a/src/header/unistd/mod.rs b/src/header/unistd/mod.rs
index 0a1214e20..96803ce71 100644
--- a/src/header/unistd/mod.rs
+++ b/src/header/unistd/mod.rs
@@ -555,9 +555,20 @@ pub extern "C" fn sleep(seconds: c_uint) -> c_uint {
0
}
-// #[no_mangle]
+#[no_mangle]
pub extern "C" fn swab(src: *const c_void, dest: *mut c_void, nbytes: ssize_t) {
- unimplemented!();
+ if nbytes <= 0 {
+ return
+ }
+ let number_of_swaps = nbytes / 2;
+ let mut offset = 0;
+ for i in 0..number_of_swaps {
+ unsafe {
+ src.offset(offset).copy_to(dest.offset(offset + 1), 1);
+ src.offset(offset + 1).copy_to(dest.offset(offset), 1);
+ }
+ offset += 2;
+ }
}
#[no_mangle]
diff --git a/tests/Makefile b/tests/Makefile
index b2e5396fd..e1bf32db6 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -81,6 +81,7 @@ EXPECT_BINS=\
unistd/pipe \
unistd/rmdir \
unistd/sleep \
+ unistd/swab \
unistd/write \
waitpid \
wchar/mbrtowc \
diff --git a/tests/expected/unistd/swab.stderr b/tests/expected/unistd/swab.stderr
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/expected/unistd/swab.stdout b/tests/expected/unistd/swab.stdout
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/unistd/swab.c b/tests/unistd/swab.c
new file mode 100644
index 000000000..c194ff280
--- /dev/null
+++ b/tests/unistd/swab.c
@@ -0,0 +1,51 @@
+#include <unistd.h>
+
+int main(int argc, char ** argv) {
+
+ const char source[] = {0, 1, 2, 3, 4, 5, 6};
+ char destination[] = {0, 0, 0, 0, 0, 0};
+ const char flipped_source[] = {1, 0, 3, 2, 5, 4};
+ const char first_two_source_bytes_flipped[] = {1, 0};
+
+ swab(source, destination, /* nbytes */ -3);
+ for (int i = 0; i < sizeof(destination); ++i) {
+ if (destination[i] != 0) {
+ puts("If nbytes is negative destionation shouldn't be modified");
+ return 1;
+ }
+ }
+
+ swab(source, destination, /* nbytes */ 0);
+ for (int i = 0; i < sizeof(destination); ++i) {
+ if (destination[i] != 0) {
+ puts("If nbytes is zero destionation shouldn't be modified");
+ return 1;
+ }
+ }
+
+ swab(source, destination, /* nbytes */ 3);
+ for (int i = 0; i < sizeof(first_two_source_bytes_flipped); ++i) {
+ if (destination[i] != first_two_source_bytes_flipped[i]) {
+ puts("copied bytes don't match expected values");
+ return 1;
+ }
+ }
+ // If nbytes is not even it's not specified what should happen to the
+ // last byte so the third byte in destination is not checked.
+ for (int i = sizeof(first_two_source_bytes_flipped) + 1; i < sizeof(destination); ++i) {
+ if (destination[i] != 0) {
+ puts("swab modified too many bytes in destination");
+ return 1;
+ }
+ }
+
+ swab(source, destination, /* nbytes */ sizeof(destination));
+ for (int i = 0; i < sizeof(destination); ++i) {
+ if (destination[i] != flipped_source[i]) {
+ puts("copied bytes don't match expected values");
+ return 1;
+ }
+ }
+
+ return 0;
+}
--
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