From b375c53c7d0a4232b85bb8dbad3dfed28a6f7278 Mon Sep 17 00:00:00 2001
From: leitner <leitner>
Date: Fri, 29 Sep 2023 17:28:11 +0000
Subject: [PATCH] get rid of undefined behavior regarding order of evaluation

---
 buffer/prs_u16.c     | 3 ++-
 buffer/prs_u16_big.c | 3 ++-
 buffer/prs_u32.c     | 5 ++++-
 buffer/prs_u32_big.c | 5 ++++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/buffer/prs_u16.c b/buffer/prs_u16.c
index 4e17e9d..1e2b819 100644
--- a/buffer/prs_u16.c
+++ b/buffer/prs_u16.c
@@ -1,7 +1,8 @@
 #include "parse.h"
 
 uint16_t prs_u16(struct bytestream* bs) {
-  return bs_get(bs) | (bs_get(bs) << 8);
+  unsigned char c = bs_get(bs);
+  return c | (bs_get(bs) << 8);
 }
 
 #ifdef UNITTEST
diff --git a/buffer/prs_u16_big.c b/buffer/prs_u16_big.c
index e02ead2..8ef66ec 100644
--- a/buffer/prs_u16_big.c
+++ b/buffer/prs_u16_big.c
@@ -1,7 +1,8 @@
 #include "parse.h"
 
 uint16_t prs_u16_big(struct bytestream* bs) {
-  return (bs_get(bs) << 8) | bs_get(bs);
+  uint16_t x = bs_get(bs) << 8;
+  return x | bs_get(bs);
 }
 
 #ifdef UNITTEST
diff --git a/buffer/prs_u32.c b/buffer/prs_u32.c
index 555bb14..f687de5 100644
--- a/buffer/prs_u32.c
+++ b/buffer/prs_u32.c
@@ -1,7 +1,10 @@
 #include "parse.h"
 
 uint32_t prs_u32(struct bytestream* bs) {
-  return bs_get(bs) | (bs_get(bs) << 8) | (bs_get(bs) << 16) | (bs_get(bs) << 24);
+  uint32_t x = bs_get(bs);
+  x |= bs_get(bs) << 8;
+  x |= bs_get(bs) << 16;
+  return x | (bs_get(bs) << 24);
 }
 
 #ifdef UNITTEST
diff --git a/buffer/prs_u32_big.c b/buffer/prs_u32_big.c
index 900071e..237e96b 100644
--- a/buffer/prs_u32_big.c
+++ b/buffer/prs_u32_big.c
@@ -1,7 +1,10 @@
 #include "parse.h"
 
 uint32_t prs_u32_big(struct bytestream* bs) {
-  return (bs_get(bs) << 24) | (bs_get(bs) << 16) | (bs_get(bs) << 8) | bs_get(bs);
+  uint32_t x = bs_get(bs) << 24;
+  x |= bs_get(bs) << 16;
+  x |= bs_get(bs) << 8;
+  return x | bs_get(bs);
 }
 
 #ifdef UNITTEST