Update snappy

.gitignore

@@ -7,3 +7,41 @@ priv
 *.la
 *~
 *.swp
+_build
+c_src/snappy/*.d
+c_src/*.d
+compile_commands.json
+
+### Elixir ###
+/_build
+/cover
+/deps
+/doc
+/.fetch
+erl_crash.dump
+*.ez
+*.beam
+/config/*.secret.exs
+.elixir_ls/
+
+### Elixir Patch ###
+
+### Erlang ###
+.eunit
+*.o
+*.plt
+.concrete/DEV_MODE
+
+# rebar 2.x
+.rebar
+rel/example_project
+ebin/*.beam
+deps
+
+# rebar 3
+.rebar3
+_build/
+_checkouts/
+
+### Erlang Patch ###
+rebar3.crashdump

Makefile

@@ -1,41 +1,14 @@
-REBAR?=rebar
+all: snappy eunit
 
+snappy:
+	./rebar3 compile
 
-.PHONY: all
-# target: all - Makes everything
-all: build
-
-
-.PHONY: build
-# target: build - Builds the project
-build:
-	$(REBAR) compile
-
-
-.PHONY: check
-# target: check - Checks if project builds and passes all the tests
-check: build eunit
+eunit:
+	./rebar3 eunit
 
+check: eunit
 
-.PHONY: clean
-# target: clean - Removes build artifacts
 clean:
-	$(REBAR) clean
-
-
-.PHONY: distclean
-# target: distclean - Removes all unversioned files
-distclean: clean
-	git clean -fxd
-
-
-.PHONY: eunit
-# target: eunit - Runs eunit test suite
-eunit:
-	$(REBAR) eunit
-
+	./rebar3 clean
+	rm -fr priv ebin
 
-.PHONY: help
-# target: help - Prints this help
-help:
-	@egrep "^# target:" Makefile | sed -e 's/^# target: //g' | sort

README.md

@@ -8,11 +8,42 @@ Google snappy's official repository and bug tracking system is at:
 
 Its source is included in this project.
 
+# changelog
+
+- tag `1.1.2` as tests pass against OTP-24
+- tag `otp-24` compatibility
+- switch build chain to [rebar3] and [enc] requiring OTP20 or newer
+- tag `snappy-1.1.8`, also first version compatible with OTP23 (thanks @skaes)
+- tag `snappy-1.1.3`
+- add a changelog
+
+[rebar3]: https://rebar3.org/
+[enc]: https://github.com/davisp/erlang-native-compiler
 
 # site
 
-https://github.com/fdmanana/snappy-erlang-nif
+https://github.com/skunkwerks/snappy-erlang-nif
+
+# credits
+
+Software is built by a few people and maintained by many. Thank-you for
+all your patches!
+
 
+- Arne Ehrlich <[email protected]>
+- Bryan Chan <[email protected]>
+- Dave Cottlehuber <[email protected]>
+- Filipe David Manana <[email protected]>
+- Joshua Scott <[email protected]>
+- Kelly McLaughlin <[email protected]>
+- Louis-Philippe Gauthier <[email protected]>
+- Mikhail Uvarov <[email protected]>
+- Peter Membrey <[email protected]>
+- Piotr Nosek <[email protected]>
+- benoitc <[email protected]>
+- @dch314
+- glejeune <[email protected]>
+- Stefan Kaes <[email protected]>
 
 # performance tests
 

c_src/snappy/snappy-internal.h

@@ -36,21 +36,30 @@
 namespace snappy {
 namespace internal {
 
+// Working memory performs a single allocation to hold all scratch space
+// required for compression.
 class WorkingMemory {
  public:
-  WorkingMemory() : large_table_(NULL) { }
-  ~WorkingMemory() { delete[] large_table_; }
+  explicit WorkingMemory(size_t input_size);
+  ~WorkingMemory();
 
   // Allocates and clears a hash table using memory in "*this",
   // stores the number of buckets in "*table_size" and returns a pointer to
   // the base of the hash table.
-  uint16* GetHashTable(size_t input_size, int* table_size);
+  uint16* GetHashTable(size_t fragment_size, int* table_size) const;
+  char* GetScratchInput() const { return input_; }
+  char* GetScratchOutput() const { return output_; }
 
  private:
-  uint16 small_table_[1<<10];    // 2KB
-  uint16* large_table_;          // Allocated only when needed
+  char* mem_;      // the allocated memory, never nullptr
+  size_t size_;    // the size of the allocated memory, never 0
+  uint16* table_;  // the pointer to the hashtable
+  char* input_;    // the pointer to the input scratch buffer
+  char* output_;   // the pointer to the output scratch buffer
 
-  DISALLOW_COPY_AND_ASSIGN(WorkingMemory);
+  // No copying
+  WorkingMemory(const WorkingMemory&);
+  void operator=(const WorkingMemory&);
 };
 
 // Flat array compression that does not emit the "uncompressed length"
@@ -70,57 +79,72 @@ char* CompressFragment(const char* input,
                        uint16* table,
                        const int table_size);
 
-// Return the largest n such that
+// Find the largest n such that
 //
 //   s1[0,n-1] == s2[0,n-1]
 //   and n <= (s2_limit - s2).
 //
+// Return make_pair(n, n < 8).
 // Does not read *s2_limit or beyond.
 // Does not read *(s1 + (s2_limit - s2)) or beyond.
 // Requires that s2_limit >= s2.
 //
-// Separate implementation for x86_64, for speed.  Uses the fact that
-// x86_64 is little endian.
-#if defined(ARCH_K8)
-static inline int FindMatchLength(const char* s1,
-                                  const char* s2,
-                                  const char* s2_limit) {
+// Separate implementation for 64-bit, little-endian cpus.
+#if !defined(SNAPPY_IS_BIG_ENDIAN) && \
+    (defined(ARCH_K8) || defined(ARCH_PPC) || defined(ARCH_ARM))
+static inline std::pair<size_t, bool> FindMatchLength(const char* s1,
+                                                      const char* s2,
+                                                      const char* s2_limit) {
   assert(s2_limit >= s2);
-  int matched = 0;
+  size_t matched = 0;
+
+  // This block isn't necessary for correctness; we could just start looping
+  // immediately.  As an optimization though, it is useful.  It creates some not
+  // uncommon code paths that determine, without extra effort, whether the match
+  // length is less than 8.  In short, we are hoping to avoid a conditional
+  // branch, and perhaps get better code layout from the C++ compiler.
+  if (SNAPPY_PREDICT_TRUE(s2 <= s2_limit - 8)) {
+    uint64 a1 = UNALIGNED_LOAD64(s1);
+    uint64 a2 = UNALIGNED_LOAD64(s2);
+    if (a1 != a2) {
+      return std::pair<size_t, bool>(Bits::FindLSBSetNonZero64(a1 ^ a2) >> 3,
+                                     true);
+    } else {
+      matched = 8;
+      s2 += 8;
+    }
+  }
 
   // Find out how long the match is. We loop over the data 64 bits at a
   // time until we find a 64-bit block that doesn't match; then we find
   // the first non-matching bit and use that to calculate the total
   // length of the match.
-  while (PREDICT_TRUE(s2 <= s2_limit - 8)) {
+  while (SNAPPY_PREDICT_TRUE(s2 <= s2_limit - 8)) {
     if (UNALIGNED_LOAD64(s2) == UNALIGNED_LOAD64(s1 + matched)) {
       s2 += 8;
       matched += 8;
     } else {
-      // On current (mid-2008) Opteron models there is a 3% more
-      // efficient code sequence to find the first non-matching byte.
-      // However, what follows is ~10% better on Intel Core 2 and newer,
-      // and we expect AMD's bsf instruction to improve.
       uint64 x = UNALIGNED_LOAD64(s2) ^ UNALIGNED_LOAD64(s1 + matched);
       int matching_bits = Bits::FindLSBSetNonZero64(x);
       matched += matching_bits >> 3;
-      return matched;
+      assert(matched >= 8);
+      return std::pair<size_t, bool>(matched, false);
     }
   }
-  while (PREDICT_TRUE(s2 < s2_limit)) {
+  while (SNAPPY_PREDICT_TRUE(s2 < s2_limit)) {
     if (s1[matched] == *s2) {
       ++s2;
       ++matched;
     } else {
-      return matched;
+      return std::pair<size_t, bool>(matched, matched < 8);
     }
   }
-  return matched;
+  return std::pair<size_t, bool>(matched, matched < 8);
 }
 #else
-static inline int FindMatchLength(const char* s1,
-                                  const char* s2,
-                                  const char* s2_limit) {
+static inline std::pair<size_t, bool> FindMatchLength(const char* s1,
+                                                      const char* s2,
+                                                      const char* s2_limit) {
   // Implementation based on the x86-64 version, above.
   assert(s2_limit >= s2);
   int matched = 0;
@@ -140,10 +164,67 @@ static inline int FindMatchLength(const char* s1,
       ++matched;
     }
   }
-  return matched;
+  return std::pair<size_t, bool>(matched, matched < 8);
 }
 #endif
 
+// Lookup tables for decompression code.  Give --snappy_dump_decompression_table
+// to the unit test to recompute char_table.
+
+enum {
+  LITERAL = 0,
+  COPY_1_BYTE_OFFSET = 1,  // 3 bit length + 3 bits of offset in opcode
+  COPY_2_BYTE_OFFSET = 2,
+  COPY_4_BYTE_OFFSET = 3
+};
+static const int kMaximumTagLength = 5;  // COPY_4_BYTE_OFFSET plus the actual offset.
+
+// Data stored per entry in lookup table:
+//      Range   Bits-used       Description
+//      ------------------------------------
+//      1..64   0..7            Literal/copy length encoded in opcode byte
+//      0..7    8..10           Copy offset encoded in opcode byte / 256
+//      0..4    11..13          Extra bytes after opcode
+//
+// We use eight bits for the length even though 7 would have sufficed
+// because of efficiency reasons:
+//      (1) Extracting a byte is faster than a bit-field
+//      (2) It properly aligns copy offset so we do not need a <<8
+static const uint16 char_table[256] = {
+  0x0001, 0x0804, 0x1001, 0x2001, 0x0002, 0x0805, 0x1002, 0x2002,
+  0x0003, 0x0806, 0x1003, 0x2003, 0x0004, 0x0807, 0x1004, 0x2004,
+  0x0005, 0x0808, 0x1005, 0x2005, 0x0006, 0x0809, 0x1006, 0x2006,
+  0x0007, 0x080a, 0x1007, 0x2007, 0x0008, 0x080b, 0x1008, 0x2008,
+  0x0009, 0x0904, 0x1009, 0x2009, 0x000a, 0x0905, 0x100a, 0x200a,
+  0x000b, 0x0906, 0x100b, 0x200b, 0x000c, 0x0907, 0x100c, 0x200c,
+  0x000d, 0x0908, 0x100d, 0x200d, 0x000e, 0x0909, 0x100e, 0x200e,
+  0x000f, 0x090a, 0x100f, 0x200f, 0x0010, 0x090b, 0x1010, 0x2010,
+  0x0011, 0x0a04, 0x1011, 0x2011, 0x0012, 0x0a05, 0x1012, 0x2012,
+  0x0013, 0x0a06, 0x1013, 0x2013, 0x0014, 0x0a07, 0x1014, 0x2014,
+  0x0015, 0x0a08, 0x1015, 0x2015, 0x0016, 0x0a09, 0x1016, 0x2016,
+  0x0017, 0x0a0a, 0x1017, 0x2017, 0x0018, 0x0a0b, 0x1018, 0x2018,
+  0x0019, 0x0b04, 0x1019, 0x2019, 0x001a, 0x0b05, 0x101a, 0x201a,
+  0x001b, 0x0b06, 0x101b, 0x201b, 0x001c, 0x0b07, 0x101c, 0x201c,
+  0x001d, 0x0b08, 0x101d, 0x201d, 0x001e, 0x0b09, 0x101e, 0x201e,
+  0x001f, 0x0b0a, 0x101f, 0x201f, 0x0020, 0x0b0b, 0x1020, 0x2020,
+  0x0021, 0x0c04, 0x1021, 0x2021, 0x0022, 0x0c05, 0x1022, 0x2022,
+  0x0023, 0x0c06, 0x1023, 0x2023, 0x0024, 0x0c07, 0x1024, 0x2024,
+  0x0025, 0x0c08, 0x1025, 0x2025, 0x0026, 0x0c09, 0x1026, 0x2026,
+  0x0027, 0x0c0a, 0x1027, 0x2027, 0x0028, 0x0c0b, 0x1028, 0x2028,
+  0x0029, 0x0d04, 0x1029, 0x2029, 0x002a, 0x0d05, 0x102a, 0x202a,
+  0x002b, 0x0d06, 0x102b, 0x202b, 0x002c, 0x0d07, 0x102c, 0x202c,
+  0x002d, 0x0d08, 0x102d, 0x202d, 0x002e, 0x0d09, 0x102e, 0x202e,
+  0x002f, 0x0d0a, 0x102f, 0x202f, 0x0030, 0x0d0b, 0x1030, 0x2030,
+  0x0031, 0x0e04, 0x1031, 0x2031, 0x0032, 0x0e05, 0x1032, 0x2032,
+  0x0033, 0x0e06, 0x1033, 0x2033, 0x0034, 0x0e07, 0x1034, 0x2034,
+  0x0035, 0x0e08, 0x1035, 0x2035, 0x0036, 0x0e09, 0x1036, 0x2036,
+  0x0037, 0x0e0a, 0x1037, 0x2037, 0x0038, 0x0e0b, 0x1038, 0x2038,
+  0x0039, 0x0f04, 0x1039, 0x2039, 0x003a, 0x0f05, 0x103a, 0x203a,
+  0x003b, 0x0f06, 0x103b, 0x203b, 0x003c, 0x0f07, 0x103c, 0x203c,
+  0x0801, 0x0f08, 0x103d, 0x203d, 0x1001, 0x0f09, 0x103e, 0x203e,
+  0x1801, 0x0f0a, 0x103f, 0x203f, 0x2001, 0x0f0b, 0x1040, 0x2040
+};
+
 }  // end namespace internal
 }  // end namespace snappy
 

c_src/snappy/snappy-stubs-internal.cc

@@ -33,7 +33,7 @@
 
 namespace snappy {
 
-void Varint::Append32(string* s, uint32 value) {
+void Varint::Append32(std::string* s, uint32 value) {
   char buf[Varint::kMax32];
   const char* p = Varint::Encode32(buf, value);
   s->append(buf, p - buf);