Use macro for wrapping += and -=

The current auto-generated += and -= implementation is hard to read, and should be replaced with += where possible. That said, we cannot auto-replace it just yet because Rust behaves differently in debug mode, therefore we should use second best approach - a macro that clearly shows intention without all the boilerplate code.

The only manual code are two macros in the src/enc/mod.rs

Use this replacement file as described in other recent PRs to replace boilerplate code.

<details>
<summary>replacement file content</summary>

```diff
@@
expression cond, expr;
@@
if cond
{
-   let _rhs = 1;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+::wrapping_add!(expr, 1);
}

@@
expression expr;
@@
-{
-   let _rhs = 1;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+::wrapping_add!(expr, 1);
-}

@@
expression expr;
@@
-{
-   let _rhs = 1u32;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs);
+::wrapping_add!(expr, 1);
-}

@@
expression expr;
@@
-{
-   let _rhs = 1i32;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+::wrapping_add!(expr, 1);
-}

@@
expression expr;
@@
-{
-   let _rhs = 1;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as usize);
+::wrapping_add!(expr, 1);
-}

@@
expression inc, expr;
@@
-{
-   let _rhs = inc;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+::wrapping_add!(expr, inc as u32);
-}

@@
expression inc, expr;
@@
-{
-   let _rhs = inc;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs);
+::wrapping_add!(expr, inc);
-}

@@
expression inc, expr;
@@
-{
-   let _rhs = inc;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+::wrapping_add!(expr, inc as u32);
-}

@@
expression inc, expr;
@@
-{
-   let _rhs = inc;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_add(_rhs as usize);
+::wrapping_add!(expr, inc as usize);
-}

@@
expression expr;
@@
-{
-   let _rhs = 1;
-   let _lhs = &mut expr;
-   *_lhs = (*_lhs).wrapping_sub(_rhs as usize);
+::wrapping_sub!(expr, 1);
-}

@@
expression expr_r, expr_l;
@@
-{
-   let _rhs = expr_r;
-   let _lhs = &mut expr_l;
-   *_lhs *= _rhs;
+expr_l *= expr_r;
-}

@@
expression expr_r, expr_l;
@@
-{
-   let _rhs = expr_r;
-   let _lhs = &mut expr_l;
-   *_lhs += _rhs;
+expr_l += expr_r;
-}

```
</details>

Author: nyurik

src/enc/backward_references/hq.rs

@@ -1244,24 +1244,17 @@ fn ZopfliCostModelSetFromCommands<AllocF: Allocator<floatX>>(
             let distcode: usize = ((commands[i]).dist_prefix_ as i32 & 0x3ff) as usize;
             let cmdcode: usize = (commands[i]).cmd_prefix_ as usize;
             let mut j: usize;
-            {
-                let _rhs = 1;
-                let _lhs = &mut histogram_cmd[cmdcode];
-                *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-            }
+            ::wrapping_add!(histogram_cmd[cmdcode], 1);
             if cmdcode >= 128usize {
-                let _rhs = 1;
-                let _lhs = &mut histogram_dist[distcode];
-                *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+                ::wrapping_add!(histogram_dist[distcode], 1);
             }
             j = 0usize;
             while j < inslength {
-                {
-                    let _rhs = 1;
-                    let _lhs = &mut histogram_literal
-                        [(ringbuffer[(pos.wrapping_add(j) & ringbuffer_mask)] as usize)];
-                    *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-                }
+                ::wrapping_add!(
+                    histogram_literal
+                        [(ringbuffer[(pos.wrapping_add(j) & ringbuffer_mask)] as usize)],
+                    1
+                );
                 j = j.wrapping_add(1);
             }
             pos = pos.wrapping_add(inslength.wrapping_add(copylength));

src/enc/block_splitter.rs

@@ -562,11 +562,7 @@ fn ClusterBlocks<
         while i < length {
             {
                 0i32;
-                {
-                    let _rhs = 1;
-                    let _lhs = &mut block_lengths.slice_mut()[block_idx];
-                    *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-                }
+                ::wrapping_add!(block_lengths.slice_mut()[block_idx], 1);
                 if i.wrapping_add(1) == length
                     || block_ids[i] as i32 != block_ids[i.wrapping_add(1)] as i32
                 {

src/enc/brotli_bit_stream.rs

@@ -923,11 +923,7 @@ pub fn BrotliStoreHuffmanTree(
     );
     i = 0usize;
     while i < huffman_tree_size {
-        {
-            let _rhs = 1;
-            let _lhs = &mut huffman_tree_histogram[huffman_tree[i] as usize];
-            *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-        }
+        ::wrapping_add!(huffman_tree_histogram[huffman_tree[i] as usize], 1);
         i = i.wrapping_add(1);
     }
     i = 0usize;
@@ -1665,15 +1661,9 @@ fn BuildAndStoreBlockSplitCode(
         {
             let type_code: usize = NextBlockTypeCode(&mut type_code_calculator, types[i]);
             if i != 0usize {
-                let _rhs = 1;
-                let _lhs = &mut type_histo[type_code];
-                *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-            }
-            {
-                let _rhs = 1;
-                let _lhs = &mut length_histo[BlockLengthPrefixCode(lengths[i]) as usize];
-                *_lhs = (*_lhs).wrapping_add(_rhs as u32);
+                ::wrapping_add!(type_histo[type_code], 1);
             }
+            ::wrapping_add!(length_histo[BlockLengthPrefixCode(lengths[i]) as usize], 1);
         }
         i = i.wrapping_add(1);
     }
@@ -1969,11 +1959,10 @@ fn EncodeContextMap<AllocU32: alloc::Allocator<u32>>(
     let mut histogram: [u32; 272] = [0; 272];
     i = 0usize;
     while i < num_rle_symbols {
-        {
-            let _rhs = 1;
-            let _lhs = &mut histogram[(rle_symbols.slice()[i] & kSymbolMask) as usize];
-            *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-        }
+        ::wrapping_add!(
+            histogram[(rle_symbols.slice()[i] & kSymbolMask) as usize],
+            1
+        );
         i = i.wrapping_add(1);
     }
     {
@@ -2868,11 +2857,7 @@ pub fn BrotliStoreMetaBlockFast<Cb, Alloc: BrotliAlloc>(
                 j = cmd.insert_len_ as usize;
                 while j != 0usize {
                     {
-                        {
-                            let _rhs = 1;
-                            let _lhs = &mut histogram[input[(pos & mask)] as usize];
-                            *_lhs = (*_lhs).wrapping_add(_rhs as u32);
-                        }
+                        ::wrapping_add!(histogram[input[(pos & mask)] as usize], 1);
                         pos = pos.wrapping_add(1);
                     }
                     j = j.wrapping_sub(1);

src/enc/cluster.rs

@@ -188,11 +188,10 @@ pub fn BrotliHistogramCombine<
         let best_idx2: u32 = (pairs[0]).idx2;
         HistogramSelfAddHistogram(out, (best_idx1 as usize), (best_idx2 as usize));
         (out[(best_idx1 as usize)]).set_bit_cost((pairs[0]).cost_combo);
-        {
-            let _rhs = cluster_size[(best_idx2 as usize)];
-            let _lhs = &mut cluster_size[(best_idx1 as usize)];
-            *_lhs = (*_lhs).wrapping_add(_rhs);
-        }
+        ::wrapping_add!(
+            cluster_size[(best_idx1 as usize)],
+            cluster_size[(best_idx2 as usize)]
+        );
         i = 0usize;
         while i < symbols_size {
             {