Merge branch 'master' into mailnews-work

1 files changed, 216 insertions, 0 deletions

diff --git a/modules/brotli/enc/hash_rolling_inc.h b/modules/brotli/enc/hash_rolling_inc.h
new file mode 100644
index 000000000..17f8a408e
--- /dev/null
+++ b/modules/brotli/enc/hash_rolling_inc.h
@@ -0,0 +1,216 @@
+/* NOLINT(build/header_guard) */
+/* Copyright 2018 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* template parameters: FN, JUMP, NUMBUCKETS, MASK, CHUNKLEN */
+/* NUMBUCKETS / (MASK + 1) = probability of storing and using hash code. */
+/* JUMP = skip bytes for speedup */
+
+/* Rolling hash for long distance long string matches. Stores one position
+   per bucket, bucket key is computed over a long region. */
+
+#define HashRolling HASHER()
+
+static const uint32_t FN(kRollingHashMul32) = 69069;
+static const uint32_t FN(kInvalidPos) = 0xffffffff;
+
+/* This hasher uses a longer forward length, but returning a higher value here
+   will hurt compression by the main hasher when combined with a composite
+   hasher. The hasher tests for forward itself instead. */
+static BROTLI_INLINE size_t FN(HashTypeLength)(void) { return 4; }
+static BROTLI_INLINE size_t FN(StoreLookahead)(void) { return 4; }
+
+/* Computes a code from a single byte. A lookup table of 256 values could be
+   used, but simply adding 1 works about as good. */
+static uint32_t FN(HashByte)(uint8_t byte) {
+  return (uint32_t)byte + 1u;
+}
+
+static uint32_t FN(HashRollingFunctionInitial)(uint32_t state, uint8_t add,
+                                               uint32_t factor) {
+  return (uint32_t)(factor * state + FN(HashByte)(add));
+}
+
+static uint32_t FN(HashRollingFunction)(uint32_t state, uint8_t add,
+                                        uint8_t rem, uint32_t factor,
+                                        uint32_t factor_remove) {
+  return (uint32_t)(factor * state +
+      FN(HashByte)(add) - factor_remove * FN(HashByte)(rem));
+}
+
+typedef struct HashRolling {
+  uint32_t state;
+  uint32_t* table;
+  size_t next_ix;
+
+  uint32_t chunk_len;
+  uint32_t factor;
+  uint32_t factor_remove;
+} HashRolling;
+
+static BROTLI_INLINE HashRolling* FN(Self)(HasherHandle handle) {
+  return (HashRolling*)&(GetHasherCommon(handle)[1]);
+}
+
+static void FN(Initialize)(
+    HasherHandle handle, const BrotliEncoderParams* params) {
+  HashRolling* self = FN(Self)(handle);
+  size_t i;
+  self->state = 0;
+  self->next_ix = 0;
+
+  self->factor = FN(kRollingHashMul32);
+
+  /* Compute the factor of the oldest byte to remove: factor**steps modulo
+     0xffffffff (the multiplications rely on 32-bit overflow) */
+  self->factor_remove = 1;
+  for (i = 0; i < CHUNKLEN; i += JUMP) {
+    self->factor_remove *= self->factor;
+  }
+
+  self->table = (uint32_t*)((HasherHandle)self + sizeof(HashRolling));
+  for (i = 0; i < NUMBUCKETS; i++) {
+    self->table[i] = FN(kInvalidPos);
+  }
+
+  BROTLI_UNUSED(params);
+}
+
+static void FN(Prepare)(HasherHandle handle, BROTLI_BOOL one_shot,
+    size_t input_size, const uint8_t* data) {
+  HashRolling* self = FN(Self)(handle);
+  size_t i;
+  /* Too small size, cannot use this hasher. */
+  if (input_size < CHUNKLEN) return;
+  self->state = 0;
+  for (i = 0; i < CHUNKLEN; i += JUMP) {
+    self->state = FN(HashRollingFunctionInitial)(
+        self->state, data[i], self->factor);
+  }
+  BROTLI_UNUSED(one_shot);
+}
+
+static BROTLI_INLINE size_t FN(HashMemAllocInBytes)(
+    const BrotliEncoderParams* params, BROTLI_BOOL one_shot,
+    size_t input_size) {
+  return sizeof(HashRolling) + NUMBUCKETS * sizeof(uint32_t);
+  BROTLI_UNUSED(params);
+  BROTLI_UNUSED(one_shot);
+  BROTLI_UNUSED(input_size);
+}
+
+static BROTLI_INLINE void FN(Store)(HasherHandle BROTLI_RESTRICT handle,
+    const uint8_t* BROTLI_RESTRICT data, const size_t mask, const size_t ix) {
+  BROTLI_UNUSED(handle);
+  BROTLI_UNUSED(data);
+  BROTLI_UNUSED(mask);
+  BROTLI_UNUSED(ix);
+}
+
+static BROTLI_INLINE void FN(StoreRange)(HasherHandle handle,
+    const uint8_t* data, const size_t mask, const size_t ix_start,
+    const size_t ix_end) {
+  BROTLI_UNUSED(handle);
+  BROTLI_UNUSED(data);
+  BROTLI_UNUSED(mask);
+  BROTLI_UNUSED(ix_start);
+  BROTLI_UNUSED(ix_end);
+}
+
+static BROTLI_INLINE void FN(StitchToPreviousBlock)(HasherHandle handle,
+    size_t num_bytes, size_t position, const uint8_t* ringbuffer,
+    size_t ring_buffer_mask) {
+  /* In this case we must re-initialize the hasher from scratch from the
+     current position. */
+  HashRolling* self = FN(Self)(handle);
+  size_t position_masked;
+  size_t available = num_bytes;
+  if ((position & (JUMP - 1)) != 0) {
+    size_t diff = JUMP - (position & (JUMP - 1));
+    available = (diff > available) ? 0 : (available - diff);
+    position += diff;
+  }
+  position_masked = position & ring_buffer_mask;
+  /* wrapping around ringbuffer not handled. */
+  if (available > ring_buffer_mask - position_masked) {
+    available = ring_buffer_mask - position_masked;
+  }
+
+  FN(Prepare)(handle, BROTLI_FALSE, available,
+      ringbuffer + (position & ring_buffer_mask));
+  self->next_ix = position;
+  BROTLI_UNUSED(num_bytes);
+}
+
+static BROTLI_INLINE void FN(PrepareDistanceCache)(
+    HasherHandle handle, int* BROTLI_RESTRICT distance_cache) {
+  BROTLI_UNUSED(handle);
+  BROTLI_UNUSED(distance_cache);
+}
+
+static BROTLI_INLINE void FN(FindLongestMatch)(HasherHandle handle,
+    const BrotliEncoderDictionary* dictionary,
+    const uint8_t* BROTLI_RESTRICT data, const size_t ring_buffer_mask,
+    const int* BROTLI_RESTRICT distance_cache, const size_t cur_ix,
+    const size_t max_length, const size_t max_backward,
+    const size_t gap, const size_t max_distance,
+    HasherSearchResult* BROTLI_RESTRICT out) {
+  HashRolling* self = FN(Self)(handle);
+  const size_t cur_ix_masked = cur_ix & ring_buffer_mask;
+  size_t pos = self->next_ix;
+
+  if ((cur_ix & (JUMP - 1)) != 0) return;
+
+  /* Not enough lookahead */
+  if (max_length < CHUNKLEN) return;
+
+  for (pos = self->next_ix; pos <= cur_ix; pos += JUMP) {
+    uint32_t code = self->state & MASK;
+
+    uint8_t rem = data[pos & ring_buffer_mask];
+    uint8_t add = data[(pos + CHUNKLEN) & ring_buffer_mask];
+    size_t found_ix = FN(kInvalidPos);
+
+    self->state = FN(HashRollingFunction)(
+        self->state, add, rem, self->factor, self->factor_remove);
+
+    if (code < NUMBUCKETS) {
+      found_ix = self->table[code];
+      self->table[code] = (uint32_t)pos;
+      if (pos == cur_ix && found_ix != FN(kInvalidPos)) {
+        /* The cast to 32-bit makes backward distances up to 4GB work even
+           if cur_ix is above 4GB, despite using 32-bit values in the table. */
+        size_t backward = (uint32_t)(cur_ix - found_ix);
+        if (backward <= max_backward) {
+          const size_t found_ix_masked = found_ix & ring_buffer_mask;
+          const size_t len = FindMatchLengthWithLimit(&data[found_ix_masked],
+                                                      &data[cur_ix_masked],
+                                                      max_length);
+          if (len >= 4 && len > out->len) {
+            score_t score = BackwardReferenceScore(len, backward);
+            if (score > out->score) {
+              out->len = len;
+              out->distance = backward;
+              out->score = score;
+              out->len_code_delta = 0;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  self->next_ix = cur_ix + JUMP;
+
+  /* NOTE: this hasher does not search in the dictionary. It is used as
+     backup-hasher, the main hasher already searches in it. */
+  BROTLI_UNUSED(dictionary);
+  BROTLI_UNUSED(distance_cache);
+  BROTLI_UNUSED(gap);
+  BROTLI_UNUSED(max_distance);
+}
+
+#undef HashRolling