From a8bc7ac119273ed88696da89287b3d31a311d1bd Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Fri, 11 Oct 2024 07:04:02 -0700
Subject: [PATCH] Import some Chromium Zlib changes

---
 third_party/zlib/crc_folding.c |  2 +-
 third_party/zlib/deflate.c     | 20 +++++++++++++++-----
 third_party/zlib/inflate.c     |  9 ++++++---
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/third_party/zlib/crc_folding.c b/third_party/zlib/crc_folding.c
index 2702f909a..cc2fa875a 100644
--- a/third_party/zlib/crc_folding.c
+++ b/third_party/zlib/crc_folding.c
@@ -406,7 +406,7 @@ partial:
     }
 #endif
 
-    _mm_storeu_si128((__m128i *)dst, xmm_crc_part);
+    memcpy(dst, src, len);  /* TODO: Possibly generate more efficient code. */
     partial_fold(s, len, &xmm_crc0, &xmm_crc1, &xmm_crc2, &xmm_crc3,
         &xmm_crc_part);
 done:
diff --git a/third_party/zlib/deflate.c b/third_party/zlib/deflate.c
index 58f9474e7..64ebcddc4 100644
--- a/third_party/zlib/deflate.c
+++ b/third_party/zlib/deflate.c
@@ -229,6 +229,8 @@ int ZEXPORT deflateInit(strm, level)
     /* To do: ignore strm->next_in if we use it as window */
 }
 
+#define WINDOW_PADDING 8
+
 /* ========================================================================= */
 int ZEXPORT deflateInit2(strm, level, method, windowBits, memLevel, strategy)
     z_streamp strm;
@@ -238,7 +240,6 @@ int ZEXPORT deflateInit2(strm, level, method, windowBits, memLevel, strategy)
     int  memLevel;
     int  strategy;
 {
-    unsigned window_padding = 8;
     deflate_state *s;
     int wrap = 1;
 
@@ -325,12 +326,12 @@ int ZEXPORT deflateInit2(strm, level, method, windowBits, memLevel, strategy)
     s->hash_shift =  ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH);
 
     s->window = (Bytef *) ZALLOC(strm,
-                                 s->w_size + window_padding,
+                                 s->w_size + WINDOW_PADDING,
                                  2*sizeof(Byte));
     /* Avoid use of unitialized values in the window, see crbug.com/1137613 and
      * crbug.com/1144420 */
     if (s->window) { /* [jart] fix regression in malloc failure checking */
-        zmemzero(s->window, (s->w_size + window_padding) * (2 * sizeof(Byte)));
+        zmemzero(s->window, (s->w_size + WINDOW_PADDING) * (2 * sizeof(Byte)));
     }
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     /* Avoid use of uninitialized value, see:
@@ -770,6 +771,12 @@ uLong ZEXPORT deflateBound(strm, sourceLen)
         wraplen = 6;
     }
 
+    /* With Chromium's hashing, s->hash_bits may not correspond to the
+       memLevel, making the computations below incorrect. Return the
+       conservative bound. */
+    if (s->chromium_zlib_hash)
+        return (fixedlen > storelen ? fixedlen : storelen) + wraplen;
+
     /* if not default parameters, return one of the conservative bounds */
     if (s->w_bits != 15 || s->hash_bits != 8 + 7)
         return (s->w_bits <= s->hash_bits ? fixedlen : storelen) + wraplen;
@@ -1199,7 +1206,9 @@ int ZEXPORT deflateCopy(dest, source)
     zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
     ds->strm = dest;
 
-    ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
+    ds->window = (Bytef *) ZALLOC(dest,
+                                  ds->w_size + WINDOW_PADDING,
+                                  2*sizeof(Byte));
     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
     ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4);
@@ -1210,7 +1219,8 @@ int ZEXPORT deflateCopy(dest, source)
         return Z_MEM_ERROR;
     }
     /* following zmemcpy do not work for 16-bit MSDOS */
-    zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
+    zmemcpy(ds->window, ss->window,
+            (ds->w_size + WINDOW_PADDING) * 2 * sizeof(Byte));
     zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
     zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
diff --git a/third_party/zlib/inflate.c b/third_party/zlib/inflate.c
index 75fa6b56e..acc88d1dc 100644
--- a/third_party/zlib/inflate.c
+++ b/third_party/zlib/inflate.c
@@ -256,6 +256,8 @@ int value;
     struct inflate_state FAR *state;
 
     if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    if (bits == 0)
+        return Z_OK;
     state = (struct inflate_state FAR *)strm->state;
     if (bits < 0) {
         state->hold = 0;
@@ -1480,7 +1482,7 @@ z_streamp strm;
     /* if first time, start search in bit buffer */
     if (state->mode != SYNC) {
         state->mode = SYNC;
-        state->hold <<= state->bits & 7;
+        state->hold >>= state->bits & 7;
         state->bits -= state->bits & 7;
         len = 0;
         while (state->bits >= 8) {
@@ -1551,8 +1553,9 @@ z_streamp source;
     if (copy == Z_NULL) return Z_MEM_ERROR;
     window = Z_NULL;
     if (state->window != Z_NULL) {
-        window = (unsigned char FAR *)
-                 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
+        window = (unsigned char FAR *)ZALLOC(
+            source, (1U << state->wbits) + CHUNKCOPY_CHUNK_SIZE,
+            sizeof(unsigned char));
         if (window == Z_NULL) {
             ZFREE(source, copy);
             return Z_MEM_ERROR;