From b43299642b24d6bec8479c980b68a9251033dc60 Mon Sep 17 00:00:00 2001
From: Tom Almeida <tommoa256@gmail.com>
Date: Fri, 21 Sep 2018 15:21:39 +0200
Subject: [PATCH] Fix buffering issue with large output through stdio
---
src/header/stdio/helpers.rs | 7 ++++++-
tests/Makefile | 1 +
tests/stdio/buffer.c | 10 ++++++++++
3 files changed, 17 insertions(+), 1 deletion(-)
create mode 100644 tests/stdio/buffer.c
diff --git a/src/header/stdio/helpers.rs b/src/header/stdio/helpers.rs
index 426e161d..f67199e8 100644
--- a/src/header/stdio/helpers.rs
+++ b/src/header/stdio/helpers.rs
@@ -97,7 +97,7 @@ pub fn fwritex(buf: *const u8, l: size_t, stream: &mut FILE) -> size_t {
// We can't write to this stream
return 0;
}
- if let Some((wbase, wpos, wend)) = stream.write {
+ if let Some((wbase, mut wpos, wend)) = stream.write {
if l > wend - wpos {
// We can't fit all of buf in the buffer
return stream.write(buf);
@@ -110,6 +110,11 @@ pub fn fwritex(buf: *const u8, l: size_t, stream: &mut FILE) -> size_t {
}
if i > 0 {
let n = stream.write(buf);
+ match stream.write {
+ Some((_, new_wpos, _)) => wpos = new_wpos,
+ None => unreachable!("stream.write should never be None after a write call")
+ }
+
if n < i {
return n;
}
diff --git a/tests/Makefile b/tests/Makefile
index f2fd7c9d..94f0a315 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -15,6 +15,7 @@ EXPECT_BINS=\
setjmp \
signal \
stdio/all \
+ stdio/buffer \
stdio/freopen \
stdio/fwrite \
stdio/getc_unget \
diff --git a/tests/stdio/buffer.c b/tests/stdio/buffer.c
new file mode 100644
index 00000000..c5d55944
--- /dev/null
+++ b/tests/stdio/buffer.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+
+int main() {
+ // Tests what used to be a bug with buffering
+ fwrite("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 1, 999, stdout);
+ fwrite("Test\n", 1, 5, stdout);
+ fwrite("Hello\nWorld\n", 1, 12, stdout);
+ puts("It works");
+ puts("No buffering issues here");
+}
--
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