From 2719d6b234da1fc36c3806038c5cffc4658044e5 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Wed, 12 Jun 2024 20:59:17 -0500
Subject: [PATCH] Replaced lfs_swap16/swap32/sswap16/etc with a macro

Seems the best way to do this in standard C.

No code changes:

           code          stack
  before: 33886           2560
  after:  33886 (+0.0%)   2560 (+0.0%)
---
 lfs.c      | 38 +++++++++++++++++++-------------------
 lfs_util.h | 35 +++++++++--------------------------
 2 files changed, 28 insertions(+), 45 deletions(-)

diff --git a/lfs.c b/lfs.c
index c3706617..e860ea0d 100644
--- a/lfs.c
+++ b/lfs.c
@@ -2921,7 +2921,7 @@ trunk:;
                         &alt, &weight,
                         p[0].alt, p[0].weight,
                         lower_rid, upper_rid);
-                lfs_swap32(&jump, &branch_);
+                LFS_SWAP(lfs_size_t, &jump, &branch_);
             }
 
             // should've taken red alt? needs a flip
@@ -2935,9 +2935,9 @@ trunk:;
                         p[0].alt, p[0].weight,
                         lower_rid, upper_rid,
                         a_rid, a_tag)) {
-                lfs_swap16(&p[0].alt, &alt);
-                lfs_swap32(&p[0].weight, &weight);
-                lfs_swap32(&p[0].jump, &jump);
+                LFS_SWAP(lfsr_tag_t, &p[0].alt, &alt);
+                LFS_SWAP(lfsr_rid_t, &p[0].weight, &weight);
+                LFS_SWAP(lfs_size_t, &p[0].jump, &jump);
                 alt = (alt & ~LFSR_TAG_R) | (p[0].alt & LFSR_TAG_R);
                 p[0].alt |= LFSR_TAG_R;
 
@@ -2945,7 +2945,7 @@ trunk:;
                         &alt, &weight,
                         p[0].alt, p[0].weight,
                         lower_rid, upper_rid);
-                lfs_swap32(&jump, &branch_);
+                LFS_SWAP(lfs_size_t, &jump, &branch_);
             }
 
             // do bounds want to take different paths? begin diverging
@@ -3125,9 +3125,9 @@ trunk:;
                 // 1  2  3  4      1  2  3  4  1
                 if (branch_ < branch) {
                     if (jump > branch) {
-                        lfs_swap16(&p[0].alt, &alt);
-                        lfs_swap32(&p[0].weight, &weight);
-                        lfs_swap32(&p[0].jump, &jump);
+                        LFS_SWAP(lfsr_tag_t, &p[0].alt, &alt);
+                        LFS_SWAP(lfsr_rid_t, &p[0].weight, &weight);
+                        LFS_SWAP(lfs_size_t, &p[0].jump, &jump);
                     }
                     alt &= ~LFSR_TAG_R;
 
@@ -3173,7 +3173,7 @@ trunk:;
                             &alt, &weight,
                             p[0].alt, p[0].weight,
                             lower_rid, upper_rid);
-                    lfs_swap32(&jump, &branch_);
+                    LFS_SWAP(lfs_size_t, &jump, &branch_);
                 }
 
             // black alt? terminate 2-3-4 nodes
@@ -3232,8 +3232,8 @@ trunk:;
                     // swap tag/rid and move on to upper trunk
                     diverged = false;
                     branch = trunk_;
-                    lfs_swap16(&a_tag, &b_tag);
-                    lfs_sswap32(&a_rid, &b_rid);
+                    LFS_SWAP(lfsr_tag_t, &a_tag, &b_tag);
+                    LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
                     goto trunk;
 
                 } else {
@@ -3580,8 +3580,8 @@ static lfs_ssize_t lfsr_rbyd_estimate(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
         if (a_dsize > b_dsize
                 // bias so lower dsize >= upper dsize
                 || (a_dsize == b_dsize && a_rid > b_rid)) {
-            lfs_sswap32(&a_rid, &b_rid);
-            lfs_swap32(&a_dsize, &b_dsize);
+            LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
+            LFS_SWAP(lfs_size_t, &a_dsize, &b_dsize);
         }
 
         if (a_rid > b_rid) {
@@ -5754,8 +5754,8 @@ static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
         if (i == 0
                 || err == LFS_ERR_CORRUPT
                 || lfs_scmp(revs[1], revs[0]) > 0) {
-            lfs_swap32(&blocks_[0], &blocks_[1]);
-            lfs_swap32(&revs[0], &revs[1]);
+            LFS_SWAP(lfs_block_t, &blocks_[0], &blocks_[1]);
+            LFS_SWAP(uint32_t, &revs[0], &revs[1]);
         }
     }
 
@@ -5773,8 +5773,8 @@ static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
             return 0;
         }
 
-        lfs_swap32(&blocks_[0], &blocks_[1]);
-        lfs_swap32(&revs[0], &revs[1]);
+        LFS_SWAP(lfs_block_t, &blocks_[0], &blocks_[1]);
+        LFS_SWAP(uint32_t, &revs[0], &revs[1]);
     }
 
     // could not find a non-corrupt rbyd
@@ -6386,8 +6386,8 @@ static lfs_ssize_t lfsr_mdir_estimate__(lfs_t *lfs, const lfsr_mdir_t *mdir,
         if (a_dsize > b_dsize
                 // bias so lower dsize >= upper dsize
                 || (a_dsize == b_dsize && a_rid > b_rid)) {
-            lfs_sswap32(&a_rid, &b_rid);
-            lfs_swap32(&a_dsize, &b_dsize);
+            LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
+            LFS_SWAP(lfs_size_t, &a_dsize, &b_dsize);
         }
 
         if (a_rid > b_rid) {
diff --git a/lfs_util.h b/lfs_util.h
index 8f4f6f77..25a13d27 100644
--- a/lfs_util.h
+++ b/lfs_util.h
@@ -193,32 +193,15 @@ static inline int32_t lfs_abs32(int32_t a) {
     return (a < 0) ? -a : a;
 }
 
-// TODO how many of these do we actually need
-// Swap two 16-bit numbers
-static inline void lfs_swap16(uint16_t *a, uint16_t *b) {
-    uint16_t t = *a;
-    *a = *b;
-    *b = t;
-}
-
-static inline void lfs_sswap16(int16_t *a, int16_t *b) {
-    int16_t t = *a;
-    *a = *b;
-    *b = t;
-}
-
-// Swap two 32-bit numbers
-static inline void lfs_swap32(uint32_t *a, uint32_t *b) {
-    uint32_t t = *a;
-    *a = *b;
-    *b = t;
-}
-
-static inline void lfs_sswap32(int32_t *a, int32_t *b) {
-    int32_t t = *a;
-    *a = *b;
-    *b = t;
-}
+// Swap two variables
+#define LFS_SWAP(_t, _a, _b) \
+    do { \
+        _t *a = _a; \
+        _t *b = _b; \
+        _t t = *a; \
+        *a = *b; \
+        *b = t; \
+    } while (0)
 
 // Align to nearest multiple of a size
 static inline uint32_t lfs_aligndown(uint32_t a, uint32_t alignment) {