From b64b9b04150c168f6de38cce340b2251a78cf245 Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Mon, 2 Jun 2025 10:25:10 +0100
Subject: [PATCH] Better `strcasestr`.

---
 sqlite3/libc/libc.wasm | Bin 6398 -> 6300 bytes
 sqlite3/libc/libc.wat  | 175 ++++++++++++++++++++++++-----------------
 sqlite3/libc/string.h  |  16 ++--
 3 files changed, 112 insertions(+), 79 deletions(-)

diff --git a/sqlite3/libc/libc.wasm b/sqlite3/libc/libc.wasm
index ba5147f25433cbe509f473668ca2881f245b1e76..821c6985bd441fe9ad1f23bbaf1f1b51db7f17f8 100755
GIT binary patch
delta 422
zcmX|-Pf7zZ6vkg(lCf=O+9Fs%H(y5Fh!%PQZIB{eC<Tw83z=D|-MN?pxa`(L2)%&b
zp?m4tGemr8MFL-vFTeLMKclzN`?FH7%eh+ZHY?4oCVPQ8BPw}f#-N@9e|XJfs6LlF
zLDgk8DF~UjT0Gb)u?Bo4wDFv?gH4nz$jN(_-aRMYK?giR%l1iiIG7%KBj+!A+<0qh
zwx*VfB`1`@|7c6j2~FPmFPwRt)&+(B9JUVqx@?1{(w>PuFZD!ov_uQAXcsD|%4_MI
zB1zw!c;_Vv3Xn{4x$%1O2wjNA85}xt%ag`gyb=CZ#^gz%#k!X-Dpbk^eyB<#si7C&
zd&k4}wG8h--UOLl2!^Rnr5;HD6nJy7X+#UVI3Jwsr|2#2a&qJ(&^VZ7Gidl14SY?-

delta 366
zcmXAky-EW?6ov2Hnce)%t_hMTD8iiyX+jk82ALvA3MF7|rG@NvYG;w!dRret2v{fY
zVCgFezQBlQVl%_s`<*%Gyv=@R?@vm7Z=TiX;rhdHYi(XcofCOpn7L5T3U6J;b5VWv
zt)Ob3FG`Z!8I75kDzRGl60~+)uoaUiQ<B9#PkYCSw~_^UlnmF7>Tt3=b<k}+rzr~u
zwQGI`183^cuYD%8gpZCr*A>Qz--4=KThE))j9U~5#+~LipBzXhu6!rnIYv&K)?Grf
zJy9fLCPiGuk#s?h;x*VC#N|b)F}O$7QlSkAKU7}BMcU2laD0(np@bE3I-mmx7F|tY
iOAw$O?;j@RH)5Kv;p8}}|8ZN8B@3apqBmzpYyJab$w77i

diff --git a/sqlite3/libc/libc.wat b/sqlite3/libc/libc.wat
index 7db9da4..2188a97 100644
--- a/sqlite3/libc/libc.wat
+++ b/sqlite3/libc/libc.wat
@@ -3700,10 +3700,13 @@
   (local $6 i32)
   (local $7 i32)
   (local $8 i32)
-  (local $9 v128)
+  (local $9 i32)
   (local $10 v128)
   (local $11 v128)
   (local $12 v128)
+  (local $13 v128)
+  (local $14 v128)
+  (local $15 v128)
   (if
    (i32.eqz
     (local.tee $2
@@ -3718,7 +3721,7 @@
     )
    )
   )
-  (local.set $5
+  (local.set $3
    (i32.extend8_s
     (local.get $2)
    )
@@ -3738,17 +3741,17 @@
      )
     )
    )
-   (local.set $4
+   (local.set $5
     (local.get $6)
    )
    (loop $label
     (if
      (i32.ne
-      (local.tee $3
+      (local.tee $4
        (i32.load8_u
         (i32.add
          (local.get $1)
-         (local.get $4)
+         (local.get $5)
         )
        )
       )
@@ -3756,15 +3759,15 @@
      )
      (then
       (local.set $2
-       (local.get $3)
+       (local.get $4)
       )
       (br $block)
      )
     )
     (br_if $label
-     (local.tee $4
+     (local.tee $5
       (i32.sub
-       (local.get $4)
+       (local.get $5)
        (i32.const 1)
       )
      )
@@ -3778,27 +3781,43 @@
      )
     )
    )
-   (local.set $4
+   (local.set $5
     (local.get $6)
    )
   )
-  (local.set $3
+  (local.set $4
    (select
     (i32.or
-     (local.get $5)
+     (local.get $3)
      (i32.const 32)
     )
-    (local.get $5)
+    (local.get $3)
     (i32.lt_u
      (i32.sub
-      (local.get $5)
+      (local.get $3)
       (i32.const 65)
      )
      (i32.const 26)
     )
    )
   )
-  (local.set $2
+  (local.set $3
+   (select
+    (i32.and
+     (local.get $3)
+     (i32.const 95)
+    )
+    (local.get $3)
+    (i32.lt_u
+     (i32.sub
+      (local.get $3)
+      (i32.const 97)
+     )
+     (i32.const 26)
+    )
+   )
+  )
+  (local.set $8
    (select
     (i32.or
      (local.tee $2
@@ -3818,19 +3837,35 @@
     )
    )
   )
+  (local.set $2
+   (select
+    (i32.and
+     (local.get $2)
+     (i32.const 95)
+    )
+    (local.get $2)
+    (i32.lt_u
+     (i32.sub
+      (local.get $2)
+      (i32.const 97)
+     )
+     (i32.const 26)
+    )
+   )
+  )
   (block $block3
    (block $block4
     (block $block1
      (br_if $block1
       (i32.lt_u
-       (local.tee $5
+       (local.tee $9
         (i32.sub
          (i32.sub
           (i32.shl
            (memory.size)
            (i32.const 16)
           )
-          (local.get $4)
+          (local.get $5)
          )
          (i32.const 16)
         )
@@ -3838,17 +3873,27 @@
        (local.get $0)
       )
      )
-     (local.set $10
+     (local.set $11
+      (i8x16.splat
+       (local.get $4)
+      )
+     )
+     (local.set $12
       (i8x16.splat
        (local.get $3)
       )
      )
-     (local.set $11
+     (local.set $13
+      (i8x16.splat
+       (local.get $8)
+      )
+     )
+     (local.set $14
       (i8x16.splat
        (local.get $2)
       )
      )
-     (local.set $8
+     (local.set $3
       (i32.add
        (local.get $1)
        (i32.const 1)
@@ -3857,24 +3902,9 @@
      (loop $label2
       (local.set $2
        (i8x16.all_true
-        (local.tee $9
-         (v128.or
-          (v128.bitselect
-           (v128.const i32x4 0x20202020 0x20202020 0x20202020 0x20202020)
-           (v128.const i32x4 0x00000000 0x00000000 0x00000000 0x00000000)
-           (i8x16.gt_s
-            (i8x16.add
-             (local.tee $9
-              (v128.load align=1
-               (local.get $0)
-              )
-             )
-             (v128.const i32x4 0x25252525 0x25252525 0x25252525 0x25252525)
-            )
-            (v128.const i32x4 0x65656565 0x65656565 0x65656565 0x65656565)
-           )
-          )
-          (local.get $9)
+        (local.tee $10
+         (v128.load align=1
+          (local.get $0)
          )
         )
        )
@@ -3882,35 +3912,34 @@
       (block $block2
        (if
         (v128.any_true
-         (local.tee $9
+         (local.tee $10
           (v128.and
-           (i8x16.eq
-            (local.get $11)
-            (v128.or
-             (v128.bitselect
-              (v128.const i32x4 0x20202020 0x20202020 0x20202020 0x20202020)
-              (v128.const i32x4 0x00000000 0x00000000 0x00000000 0x00000000)
-              (i8x16.gt_s
-               (i8x16.add
-                (local.tee $12
-                 (v128.load align=1
-                  (i32.add
-                   (local.get $0)
-                   (local.get $4)
-                  )
-                 )
-                )
-                (v128.const i32x4 0x25252525 0x25252525 0x25252525 0x25252525)
+           (v128.or
+            (i8x16.eq
+             (local.get $13)
+             (local.tee $15
+              (v128.load align=1
+               (i32.add
+                (local.get $0)
+                (local.get $5)
                )
-               (v128.const i32x4 0x65656565 0x65656565 0x65656565 0x65656565)
               )
              )
-             (local.get $12)
+            )
+            (i8x16.eq
+             (local.get $14)
+             (local.get $15)
             )
            )
-           (i8x16.eq
-            (local.get $10)
-            (local.get $9)
+           (v128.or
+            (i8x16.eq
+             (local.get $11)
+             (local.get $10)
+            )
+            (i8x16.eq
+             (local.get $12)
+             (local.get $10)
+            )
            )
           )
          )
@@ -3925,7 +3954,7 @@
           (i32.eqz
            (local.tee $2
             (i8x16.bitmask
-             (local.get $9)
+             (local.get $10)
             )
            )
           )
@@ -3935,7 +3964,7 @@
            (i32.eqz
             (call $strncasecmp
              (i32.add
-              (local.tee $3
+              (local.tee $4
                (i32.add
                 (local.get $0)
                 (i32.ctz
@@ -3945,7 +3974,7 @@
               )
               (i32.const 1)
              )
-             (local.get $8)
+             (local.get $3)
              (local.get $6)
             )
            )
@@ -3979,12 +4008,12 @@
           (i32.const 16)
          )
         )
-        (local.get $5)
+        (local.get $9)
        )
       )
      )
     )
-    (local.set $3
+    (local.set $4
      (local.get $0)
     )
     (local.set $2
@@ -3997,7 +4026,7 @@
         (i32.load8_s
          (i32.add
           (local.get $2)
-          (local.get $3)
+          (local.get $4)
          )
         )
        )
@@ -4007,7 +4036,7 @@
       (i32.eq
        (select
         (i32.or
-         (local.tee $4
+         (local.tee $5
           (i32.load8_s
            (i32.add
             (local.get $1)
@@ -4017,10 +4046,10 @@
          )
          (i32.const 32)
         )
-        (local.get $4)
+        (local.get $5)
         (i32.lt_u
          (i32.sub
-          (local.get $4)
+          (local.get $5)
           (i32.const 65)
          )
          (i32.const 26)
@@ -4055,9 +4084,9 @@
        )
       )
       (else
-       (local.set $3
+       (local.set $4
         (i32.add
-         (local.get $3)
+         (local.get $4)
          (i32.const 1)
         )
        )
@@ -4070,11 +4099,11 @@
     )
     (unreachable)
    )
-   (local.set $3
+   (local.set $4
     (i32.const 0)
    )
   )
-  (local.get $3)
+  (local.get $4)
  )
  (func $memccpy (param $0 i32) (param $1 i32) (param $2 i32) (param $3 i32) (result i32)
   (memory.copy
diff --git a/sqlite3/libc/string.h b/sqlite3/libc/string.h
index fed1c8f..e1314ef 100644
--- a/sqlite3/libc/string.h
+++ b/sqlite3/libc/string.h
@@ -616,18 +616,22 @@ char *strcasestr(const char *haystk, const char *needle) {
   while (i > 0 && needle[0] == needle[i]) i--;
   if (i == 0) i = sn - 1;
 
-  const v128_t fst = wasm_i8x16_splat(tolower(needle[0]));
-  const v128_t lst = wasm_i8x16_splat(tolower(needle[i]));
+  const v128_t fstl = wasm_i8x16_splat(tolower(needle[0]));
+  const v128_t fstu = wasm_i8x16_splat(toupper(needle[0]));
+  const v128_t lstl = wasm_i8x16_splat(tolower(needle[i]));
+  const v128_t lstu = wasm_i8x16_splat(toupper(needle[i]));
 
   // The last haystk offset for which loading blk_lst is safe.
   const char *H =
       (char *)(__builtin_wasm_memory_size(0) * PAGESIZE - i - sizeof(v128_t));
 
   while (haystk <= H) {
-    const v128_t blk_fst = __tolower8x16(wasm_v128_load((v128_t *)(haystk)));
-    const v128_t blk_lst = __tolower8x16(wasm_v128_load((v128_t *)(haystk + i)));
-    const v128_t eq_fst = wasm_i8x16_eq(fst, blk_fst);
-    const v128_t eq_lst = wasm_i8x16_eq(lst, blk_lst);
+    const v128_t blk_fst = wasm_v128_load((v128_t *)(haystk));
+    const v128_t blk_lst = wasm_v128_load((v128_t *)(haystk + i));
+    const v128_t eq_fst =
+        wasm_i8x16_eq(fstl, blk_fst) | wasm_i8x16_eq(fstu, blk_fst);
+    const v128_t eq_lst =
+        wasm_i8x16_eq(lstl, blk_lst) | wasm_i8x16_eq(lstu, blk_lst);
 
     const v128_t cmp = eq_fst & eq_lst;
     if (wasm_v128_any_true(cmp)) {