fix order with repr(C)

Benchmark 1 (161 runs): ./uncompress-baseline rs silesia-small.tar.gz
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          31.0ms ± 1.16ms    30.2ms … 43.6ms          4 ( 2%)        0%
  peak_rss           24.1MB ± 65.2KB    23.9MB … 24.1MB          0 ( 0%)        0%
  cpu_cycles         90.1M  ± 3.33M     89.4M  …  129M          12 ( 7%)        0%
  instructions        273M  ±  409       273M  …  273M           2 ( 1%)        0%
  cache_references   2.11M  ±  101K     2.04M  … 2.99M           8 ( 5%)        0%
  cache_misses       29.9K  ± 2.87K     27.4K  … 61.0K           4 ( 2%)        0%
  branch_misses       953K  ±  942       951K  …  961K          10 ( 6%)        0%
Benchmark 2 (163 runs): ./target/release/examples/blogpost-uncompress rs silesia-small.tar.gz
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          30.7ms ±  304us    30.1ms … 32.3ms          1 ( 1%)          -  1.0% ±  0.6%
  peak_rss           24.1MB ± 63.2KB    24.0MB … 24.1MB          0 ( 0%)          +  0.0% ±  0.1%
  cpu_cycles         88.3M  ±  563K     88.0M  … 94.2M          10 ( 6%)        ⚡-  2.0% ±  0.6%
  instructions        267M  ±  266       267M  …  267M           0 ( 0%)        ⚡-  2.4% ±  0.0%
  cache_references   2.10M  ±  105K     2.05M  … 3.20M           5 ( 3%)          -  0.5% ±  1.1%
  cache_misses       26.6K  ± 1.28K     24.3K  … 31.1K           6 ( 4%)        ⚡- 11.0% ±  1.6%
  branch_misses       953K  ±  818       952K  …  960K           6 ( 4%)          +  0.1% ±  0.0%

zlib-rs/src/inflate.rs

@@ -305,11 +305,6 @@ impl Flags {
  self.0 & other.0 != 0
  }
 
- #[inline(always)]
- pub(crate) fn union(&mut self, other: Self) {
- *self = Self(self.0 | other.0);
- }
-
  #[inline(always)]
  pub(crate) fn update(&mut self, other: Self, value: bool) {
  if value {
@@ -320,8 +315,7 @@ impl Flags {
  }
 }
 
-const _SIZE: [u8; 14608] = [0; core::mem::size_of::<State>()];
-
+#[repr(C, align(64))]
 pub(crate) struct State<'a> {
  /// Current inflate mode
  mode: Mode,
@@ -338,11 +332,11 @@ pub(crate) struct State<'a> {
  /// - bit 2 true to validate check value
  wrap: u8,
 
+ flush: InflateFlush,
+
  // allocated window if needed (capacity == 0 if unused)
  window: Window<'a>,
 
- _padding0: usize,
-
  //
  /// number of code length code lengths
  ncode: usize,
@@ -381,21 +375,16 @@ pub(crate) struct State<'a> {
  in_available: usize,
  out_available: usize,
 
- /// temporary storage space for code lengths
- lens: [u16; 320],
- /// work area for code table building
- work: [u16; 288],
-
- error_message: Option<&'static str>,
- flush: InflateFlush,
+ gzip_flags: i32,
 
  checksum: u32,
  crc_fold: Crc32Fold,
 
+ error_message: Option<&'static str>,
+
  /// place to store gzip header if needed
  head: Option<&'a mut gz_header>,
  dmax: usize,
- gzip_flags: i32,
 
  /// table for length/literal codes
  len_table: Table,
@@ -406,6 +395,11 @@ pub(crate) struct State<'a> {
  codes_codes: [Code; crate::ENOUGH_LENS],
  len_codes: [Code; crate::ENOUGH_LENS],
  dist_codes: [Code; crate::ENOUGH_DISTS],
+
+ /// temporary storage space for code lengths
+ lens: [u16; 320],
+ /// work area for code table building
+ work: [u16; 288],
 }
 
 impl<'a> State<'a> {
@@ -455,7 +449,6 @@ impl<'a> State<'a> {
  checksum: 0,
  crc_fold: Crc32Fold::new(),
 
- _padding0: 0,
  dmax: 0,
  gzip_flags: 0,
 
@@ -2155,7 +2148,6 @@ pub unsafe fn copy<'a>(
  flush: state.flush,
  checksum: state.checksum,
  crc_fold: state.crc_fold,
- _padding0: state._padding0,
  dmax: state.dmax,
  gzip_flags: state.gzip_flags,
  codes_codes: state.codes_codes,