Initial work on Rust port

.gitignore

@@ -3,7 +3,9 @@ lib/
 esm/
 .DS_STORE
 # Rust version - available when ready
-rs/
+rs/target/
+rs/Cargo.lock
+
 .DS_STORE
 umd/
 # for demo

package.json

@@ -18,6 +18,7 @@
     "types": false
   },
   "sideEffects": false,
+  "homepage": "https://101arrowz.github.io/fflate",
   "repository": "https://github.com/101arrowz/fflate",
   "author": "Arjun Barrett",
   "license": "MIT",

rs/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "fflate"
+version = "0.0.1"
+authors = ["Arjun Barrett <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+lazy_static = "^1.4.0"

rs/src/lib.rs

@@ -0,0 +1,168 @@
+//! fflate - a fast, efficient, pure compression library
+//!
+//!
+
+// Instead of trying to read this code, check out the TypeScript version
+
+#![allow(non_upper_case_globals)]
+#![no_std]
+
+extern crate alloc;
+
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use lazy_static::lazy_static;
+
+macro_rules! BM {
+    ($num:expr) => {
+        (1 << $num) - 1
+    };
+}
+
+const fleb: [u8; 32] = [
+    0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0, 0,
+];
+
+const fl: [u16; 32] = [
+    3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131,
+    163, 195, 227, 258, 0, 0, 0,
+];
+
+// in theory, this could be computed, but embedding it at compile time is faster.
+const flt: [u8; 288] = [
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8,
+];
+
+const fdeb: [u8; 32] = [
+    0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13,
+    13, 0, 0,
+];
+
+const fd: [u16; 32] = [
+    1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537,
+    2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0,
+];
+
+const fdt: [u8; 31] = [5u8; 31];
+
+const clim: [u8; 19] = [
+    16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15,
+];
+
+fn uvec<T>(sz: usize) -> Vec<T> {
+    let mut v = Vec::with_capacity(sz);
+    unsafe {
+        v.set_len(sz);
+    }
+    v
+}
+
+fn freb(b: &[u16], r: &mut [u32]) {
+    for i in 1..30 {
+        let base = b[i];
+        for j in base..b[i + 1] {
+            r[j as usize] = ((j - base) << 5) as u32 | i as u32;
+        }
+    }
+}
+
+// hmap base
+fn hmb(cd: &[u8], mb: u8) -> [u16; 16] {
+    let mut l = [0u16; 16];
+    for &cl in cd {
+        l[cl as usize] += 1;
+    }
+    let mut le = [0u16; 16];
+    let mut v = 0;
+    for i in 1..mb {
+        v += l[i as usize];
+        le[i as usize] = v;
+    }
+    le
+}
+
+fn hmap(cd: &[u8], mb: u8) -> Box<[u16]> {
+    let mut le = hmb(cd, mb);
+    cd.iter()
+        .map(|&cl| {
+            let v = rev[le[cl as usize] as usize] >> (15 - cl);
+            le[cl as usize] += 1;
+            v
+        })
+        .collect::<Vec<_>>()
+        .into_boxed_slice()
+}
+
+fn hrmap(cd: &[u8], mb: u8) -> Box<[u16]> {
+    let mut le = hmb(cd, mb);
+    let mut co = uvec(1 << mb).into_boxed_slice();
+    let rvb = 15 - mb;
+    for i in 0..cd.len() {
+        let cl = cd[i];
+        if cl != 0 {
+            let sv = ((i as u16) << 4) | cl as u16;
+            let r = mb - cl;
+            let v = le[cl as usize] << r;
+            le[cl as usize] += 1;
+            let m = v + (1 << r);
+            for j in v..m {
+                co[rev[j as usize] as usize >> rvb] = sv;
+            }
+        }
+    }
+    co
+}
+
+lazy_static! {
+    static ref revfl: Box<[u32]> = {
+        let mut v = Vec::with_capacity(261).into_boxed_slice();
+        freb(&fl, &mut v);
+        v
+    };
+    static ref revfd: Box<[u32]> = {
+        let mut v = Vec::with_capacity(32769).into_boxed_slice();
+        freb(&fd, &mut v);
+        v
+    };
+    static ref rev: Box<[u16]> = (0..32768)
+        .map(|mut v| {
+            v = ((v & 0xAAAA) >> 1) | ((v & 0x5555) << 1);
+            v = ((v & 0xCCCC) >> 2) | ((v & 0x3333) << 2);
+            v = ((v & 0xF0F0) >> 4) | ((v & 0x0F0F) << 4);
+            (((v & 0xFF00) >> 8) | ((v & 0x00FF) << 8)) >> 1
+        })
+        .collect::<Vec<_>>()
+        .into_boxed_slice();
+    static ref flm: Box<[u16]> = hmap(&flt, 9);
+    static ref flrm: Box<[u16]> = hrmap(&flt, 9);
+    static ref fdm: Box<[u16]> = hmap(&fdt, 5);
+    static ref fdrm: Box<[u16]> = hrmap(&flt, 5);
+}
+
+#[inline]
+fn bits(dat: &[u8], pos: usize, mask: u8) -> u8 {
+    let b = pos >> 3;
+    return ((dat[b] as u16 | ((dat[b + 1] as u16) << 8)) >> (pos & 7)) as u8 & mask;
+}
+
+#[inline]
+fn bits16(dat: &[u8], pos: usize, mask: u16) -> u16 {
+    let b = pos >> 3;
+    return ((dat[b] as u32 | ((dat[b + 1] as u32) << 8) | ((dat[b + 2] as u32) << 16)) >> (pos & 7))
+        as u16
+        & mask;
+}
+
+#[inline(always)]
+fn shft(pos: usize) -> usize {
+    pos >> 3 + (pos & 7 != 0) as usize
+}
+

src/index.ts

@@ -15,16 +15,12 @@ import wk from './node-worker';
 // aliases for shorter compressed code (most minifers don't do this)
 const u8 = Uint8Array, u16 = Uint16Array, u32 = Uint32Array;
 
-const mskr = (v: Uint8Array, o: Uint8Array | Uint16Array) => {
-  for (let i = 0; i < 32; ++i) o[i] = (1 << v[i]) - 1;
-  return o;
-}
 // fixed length extra bits
-const fleb = new u8([0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, /* unused */ 0, 0, /* impossible */ 0]), flebmsk = mskr(fleb, new u8(32));
+const fleb = new u8([0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, /* unused */ 0, 0, /* impossible */ 0]);
 
 // fixed distance extra bits
 // see fleb note
-const fdeb = new u8([0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, /* unused */ 0, 0]), fdebmsk = mskr(fdeb, new u16(32));
+const fdeb = new u8([0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, /* unused */ 0, 0]);
 
 // code length index map
 const clim = new u8([16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15]);
@@ -53,11 +49,11 @@ const [fd, revfd] = freb(fdeb, 0);
 // map of value to reverse (assuming 16 bits)
 const rev = new u16(32768);
 for (let i = 0; i < 32768; ++i) {
-  // reverse table algorithm from UZIP.js
-  let x = ((i & 0xAAAAAAAA) >>> 1) | ((i & 0x55555555) << 1);
-  x = ((x & 0xCCCCCCCC) >>> 2) | ((x & 0x33333333) << 2);
-  x = ((x & 0xF0F0F0F0) >>> 4) | ((x & 0x0F0F0F0F) << 4);
-  rev[i] = (((x & 0xFF00FF00) >>> 8) | ((x & 0x00FF00FF) << 8)) >>> 1;
+  // reverse table algorithm from SO
+  let x = ((i & 0xAAAA) >>> 1) | ((i & 0x5555) << 1);
+  x = ((x & 0xCCCC) >>> 2) | ((x & 0x3333) << 2);
+  x = ((x & 0xF0F0) >>> 4) | ((x & 0x0F0F) << 4);
+  rev[i] = (((x & 0xFF00) >>> 8) | ((x & 0x00FF) << 8)) >>> 1;
 }
 
 // create huffman tree from u8 "map": index -> code length for code index
@@ -292,16 +288,19 @@ const inflt = (dat: Uint8Array, buf?: Uint8Array, st?: InflateState) => {
         // no extra bits needed if less
         if (sym > 264) {
           // index
-          const i = sym - 257;
-          add = bits(dat, pos, flebmsk[i]) + fl[i];
-          pos += fleb[i];
+          const i = sym - 257, b = fleb[i];
+          add = bits(dat, pos, (1 << b) - 1) + fl[i];
+          pos += b;
         }
         // dist
         const d = dm[bits16(dat, pos) & dms], dsym = d >>> 4;
         if (!d) throw 'invalid distance';
         pos += d & 15;
         let dt = fd[dsym];
-        if (dsym > 3) dt += bits16(dat, pos) & fdebmsk[dsym], pos += fdeb[dsym];
+        if (dsym > 3) {
+          const b = fdeb[dsym];
+          dt += bits16(dat, pos) & ((1 << b) - 1), pos += b;
+        }
         if (pos > tbts) throw 'unexpected EOF';
         if (noBuf) cbuf(bt + 131072);
         const end = bt + add;
@@ -908,7 +907,7 @@ const wrkr = <T, R>(fns: (() => unknown[])[], init: (ev: MessageEvent<T>) => voi
 }
 
 // base async inflate fn
-const bInflt = () => [u8, u16, fleb, flebmsk, fdeb, fdebmsk, clim, fl, fd, flrm, fdrm, rev, hMap, max, bits, bits16, shft, slc, inflt, inflateSync, pbf, gu8];
+const bInflt = () => [u8, u16, fleb, fdeb, clim, fl, fd, flrm, fdrm, rev, hMap, max, bits, bits16, shft, slc, inflt, inflateSync, pbf, gu8];
 const bDflt = () => [u8, u16, u32, fleb, fdeb, clim, revfl, revfd, flm, flt, fdm, fdt, rev, deo, et, hMap, wbits, wbits16, hTree, ln, lc, clen, wfblk, wblk, shft, slc, dflt, dopt, deflateSync, pbf]
 
 // gzip extra