Added: couchdb/trunk/src/snappy/google-snappy/snappy-stubs-internal.h
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/google-snappy/snappy-stubs-internal.h?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/google-snappy/snappy-stubs-internal.h (added)
+++ couchdb/trunk/src/snappy/google-snappy/snappy-stubs-internal.h Mon May  2 13:28:20 2011
@@ -0,0 +1,477 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the open-source version of Snappy.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <iostream>
+#include <string>
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_SYS_MMAN
+#include <sys/mman.h>
+#endif
+
+#include "snappy-stubs-public.h"
+
+#if defined(__x86_64__)
+
+// Enable 64-bit optimized versions of some routines.
+#define ARCH_K8 1
+
+#endif
+
+// Needed by OS X, among others.
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
+// Pull in std::min, std::ostream, and the likes. This is safe because this
+// header file is never used from any public header files.
+using namespace std;
+
+// The size of an array, if known at compile-time.
+// Will give unexpected results if used on a pointer.
+// We undefine it first, since some compilers already have a definition.
+#ifdef ARRAYSIZE
+#undef ARRAYSIZE
+#endif
+#define ARRAYSIZE(a) (sizeof(a) / sizeof(*(a)))
+
+// Static prediction hints.
+#ifdef HAVE_BUILTIN_EXPECT
+#define PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
+#define PREDICT_FALSE(x) x
+#define PREDICT_TRUE(x) x
+#endif
+
+// This is only used for recomputing the tag byte table used during
+// decompression; for simplicity we just remove it from the open-source
+// version (anyone who wants to regenerate it can just do the call
+// themselves within main()).
+#define DEFINE_bool(flag_name, default_value, description) \
+  bool FLAGS_ ## flag_name = default_value;
+#define DECLARE_bool(flag_name) \
+  extern bool FLAGS_ ## flag_name;
+#define REGISTER_MODULE_INITIALIZER(name, code)
+
+namespace snappy {
+
+static const uint32 kuint32max = static_cast<uint32>(0xFFFFFFFF);
+static const int64 kint64max = static_cast<int64>(0x7FFFFFFFFFFFFFFFLL);
+
+// Logging.
+
+#define LOG(level) LogMessage()
+#define VLOG(level) true ? (void)0 : \
+    snappy::LogMessageVoidify() & snappy::LogMessage()
+
+class LogMessage {
+ public:
+  LogMessage() { }
+  ~LogMessage() {
+    cerr << endl;
+  }
+
+  LogMessage& operator<<(const std::string& msg) {
+    cerr << msg;
+    return *this;
+  }
+  LogMessage& operator<<(int x) {
+    cerr << x;
+    return *this;
+  }
+};
+
+// Asserts, both versions activated in debug mode only,
+// and ones that are always active.
+
+#define CRASH_UNLESS(condition) \
+    PREDICT_TRUE(condition) ? (void)0 : \
+    snappy::LogMessageVoidify() & snappy::LogMessageCrash()
+
+class LogMessageCrash : public LogMessage {
+ public:
+  LogMessageCrash() { }
+  ~LogMessageCrash() {
+    cerr << endl;
+    abort();
+  }
+};
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros.  This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+
+class LogMessageVoidify {
+ public:
+  LogMessageVoidify() { }
+  // This has to be an operator with a precedence lower than << but
+  // higher than ?:
+  void operator&(const LogMessage&) { }
+};
+
+#define CHECK(cond) CRASH_UNLESS(cond)
+#define CHECK_LE(a, b) CRASH_UNLESS((a) <= (b))
+#define CHECK_GE(a, b) CRASH_UNLESS((a) >= (b))
+#define CHECK_EQ(a, b) CRASH_UNLESS((a) == (b))
+#define CHECK_NE(a, b) CRASH_UNLESS((a) != (b))
+#define CHECK_LT(a, b) CRASH_UNLESS((a) < (b))
+#define CHECK_GT(a, b) CRASH_UNLESS((a) > (b))
+
+#ifdef NDEBUG
+
+#define DCHECK(cond) CRASH_UNLESS(true)
+#define DCHECK_LE(a, b) CRASH_UNLESS(true)
+#define DCHECK_GE(a, b) CRASH_UNLESS(true)
+#define DCHECK_EQ(a, b) CRASH_UNLESS(true)
+#define DCHECK_NE(a, b) CRASH_UNLESS(true)
+#define DCHECK_LT(a, b) CRASH_UNLESS(true)
+#define DCHECK_GT(a, b) CRASH_UNLESS(true)
+
+#else
+
+#define DCHECK(cond) CHECK(cond)
+#define DCHECK_LE(a, b) CHECK_LE(a, b)
+#define DCHECK_GE(a, b) CHECK_GE(a, b)
+#define DCHECK_EQ(a, b) CHECK_EQ(a, b)
+#define DCHECK_NE(a, b) CHECK_NE(a, b)
+#define DCHECK_LT(a, b) CHECK_LT(a, b)
+#define DCHECK_GT(a, b) CHECK_GT(a, b)
+
+#endif
+
+// Potentially unaligned loads and stores.
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
+
+#define UNALIGNED_LOAD16(_p) (*reinterpret_cast<const uint16 *>(_p))
+#define UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32 *>(_p))
+#define UNALIGNED_LOAD64(_p) (*reinterpret_cast<const uint64 *>(_p))
+
+#define UNALIGNED_STORE16(_p, _val) (*reinterpret_cast<uint16 *>(_p) = (_val))
+#define UNALIGNED_STORE32(_p, _val) (*reinterpret_cast<uint32 *>(_p) = (_val))
+#define UNALIGNED_STORE64(_p, _val) (*reinterpret_cast<uint64 *>(_p) = (_val))
+
+#else
+
+// These functions are provided for architectures that don't support
+// unaligned loads and stores.
+
+inline uint16 UNALIGNED_LOAD16(const void *p) {
+  uint16 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline uint32 UNALIGNED_LOAD32(const void *p) {
+  uint32 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline uint64 UNALIGNED_LOAD64(const void *p) {
+  uint64 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline void UNALIGNED_STORE16(void *p, uint16 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+inline void UNALIGNED_STORE32(void *p, uint32 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+inline void UNALIGNED_STORE64(void *p, uint64 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+#endif
+
+// The following guarantees declaration of the byte swap functions.
+#ifdef WORDS_BIGENDIAN
+
+#ifdef _MSC_VER
+#include <stdlib.h>
+#define bswap_16(x) _byteswap_ushort(x)
+#define bswap_32(x) _byteswap_ulong(x)
+#define bswap_64(x) _byteswap_uint64(x)
+
+#elif defined(__APPLE__)
+// Mac OS X / Darwin features
+#include <libkern/OSByteOrder.h>
+#define bswap_16(x) OSSwapInt16(x)
+#define bswap_32(x) OSSwapInt32(x)
+#define bswap_64(x) OSSwapInt64(x)
+
+#else
+#include <byteswap.h>
+#endif
+
+#endif  // WORDS_BIGENDIAN
+
+// Convert to little-endian storage, opposite of network format.
+// Convert x from host to little endian: x = LittleEndian.FromHost(x);
+// convert x from little endian to host: x = LittleEndian.ToHost(x);
+//
+//  Store values into unaligned memory converting to little endian order:
+//    LittleEndian.Store16(p, x);
+//
+//  Load unaligned values stored in little endian converting to host order:
+//    x = LittleEndian.Load16(p);
+class LittleEndian {
+ public:
+  // Conversion functions.
+#ifdef WORDS_BIGENDIAN
+
+  static uint16 FromHost16(uint16 x) { return bswap_16(x); }
+  static uint16 ToHost16(uint16 x) { return bswap_16(x); }
+
+  static uint32 FromHost32(uint32 x) { return bswap_32(x); }
+  static uint32 ToHost32(uint32 x) { return bswap_32(x); }
+
+  static bool IsLittleEndian() { return false; }
+
+#else  // !defined(WORDS_BIGENDIAN)
+
+  static uint16 FromHost16(uint16 x) { return x; }
+  static uint16 ToHost16(uint16 x) { return x; }
+
+  static uint32 FromHost32(uint32 x) { return x; }
+  static uint32 ToHost32(uint32 x) { return x; }
+
+  static bool IsLittleEndian() { return true; }
+
+#endif  // !defined(WORDS_BIGENDIAN)
+
+  // Functions to do unaligned loads and stores in little-endian order.
+  static uint16 Load16(const void *p) {
+    return ToHost16(UNALIGNED_LOAD16(p));
+  }
+
+  static void Store16(void *p, uint16 v) {
+    UNALIGNED_STORE16(p, FromHost16(v));
+  }
+
+  static uint32 Load32(const void *p) {
+    return ToHost32(UNALIGNED_LOAD32(p));
+  }
+
+  static void Store32(void *p, uint32 v) {
+    UNALIGNED_STORE32(p, FromHost32(v));
+  }
+};
+
+// Some bit-manipulation functions.
+class Bits {
+ public:
+  // Return floor(log2(n)) for positive integer n.  Returns -1 iff n == 0.
+  static int Log2Floor(uint32 n);
+
+  // Return the first set least / most significant bit, 0-indexed.  Returns an
+  // undefined value if n == 0.  FindLSBSetNonZero() is similar to ffs() except
+  // that it's 0-indexed.
+  static int FindLSBSetNonZero(uint32 n);
+  static int FindLSBSetNonZero64(uint64 n);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Bits);
+};
+
+#ifdef HAVE_BUILTIN_CTZ
+
+inline int Bits::Log2Floor(uint32 n) {
+  return n == 0 ? -1 : 31 ^ __builtin_clz(n);
+}
+
+inline int Bits::FindLSBSetNonZero(uint32 n) {
+  return __builtin_ctz(n);
+}
+
+inline int Bits::FindLSBSetNonZero64(uint64 n) {
+  return __builtin_ctzll(n);
+}
+
+#else  // Portable versions.
+
+inline int Bits::Log2Floor(uint32 n) {
+  if (n == 0)
+    return -1;
+  int log = 0;
+  uint32 value = n;
+  for (int i = 4; i >= 0; --i) {
+    int shift = (1 << i);
+    uint32 x = value >> shift;
+    if (x != 0) {
+      value = x;
+      log += shift;
+    }
+  }
+  assert(value == 1);
+  return log;
+}
+
+inline int Bits::FindLSBSetNonZero(uint32 n) {
+  int rc = 31;
+  for (int i = 4, shift = 1 << 4; i >= 0; --i) {
+    const uint32 x = n << shift;
+    if (x != 0) {
+      n = x;
+      rc -= shift;
+    }
+    shift >>= 1;
+  }
+  return rc;
+}
+
+// FindLSBSetNonZero64() is defined in terms of FindLSBSetNonZero().
+inline int Bits::FindLSBSetNonZero64(uint64 n) {
+  const uint32 bottombits = static_cast<uint32>(n);
+  if (bottombits == 0) {
+    // Bottom bits are zero, so scan in top bits
+    return 32 + FindLSBSetNonZero(static_cast<uint32>(n >> 32));
+  } else {
+    return FindLSBSetNonZero(bottombits);
+  }
+}
+
+#endif  // End portable versions.
+
+// Variable-length integer encoding.
+class Varint {
+ public:
+  // Maximum lengths of varint encoding of uint32.
+  static const int kMax32 = 5;
+
+  // Attempts to parse a varint32 from a prefix of the bytes in [ptr,limit-1].
+  // Never reads a character at or beyond limit.  If a valid/terminated varint32
+  // was found in the range, stores it in *OUTPUT and returns a pointer just
+  // past the last byte of the varint32. Else returns NULL.  On success,
+  // "result <= limit".
+  static const char* Parse32WithLimit(const char* ptr, const char* limit,
+                                      uint32* OUTPUT);
+
+  // REQUIRES   "ptr" points to a buffer of length sufficient to hold "v".
+  // EFFECTS    Encodes "v" into "ptr" and returns a pointer to the
+  //            byte just past the last encoded byte.
+  static char* Encode32(char* ptr, uint32 v);
+
+  // EFFECTS    Appends the varint representation of "value" to "*s".
+  static void Append32(string* s, uint32 value);
+};
+
+inline const char* Varint::Parse32WithLimit(const char* p,
+                                            const char* l,
+                                            uint32* OUTPUT) {
+  const unsigned char* ptr = reinterpret_cast<const unsigned char*>(p);
+  const unsigned char* limit = reinterpret_cast<const unsigned char*>(l);
+  uint32 b, result;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result = b & 127;          if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) <<  7; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 14; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 21; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 28; if (b < 16) goto done;
+  return NULL;       // Value is too long to be a varint32
+ done:
+  *OUTPUT = result;
+  return reinterpret_cast<const char*>(ptr);
+}
+
+inline char* Varint::Encode32(char* sptr, uint32 v) {
+  // Operate on characters as unsigneds
+  unsigned char* ptr = reinterpret_cast<unsigned char*>(sptr);
+  static const int B = 128;
+  if (v < (1<<7)) {
+    *(ptr++) = v;
+  } else if (v < (1<<14)) {
+    *(ptr++) = v | B;
+    *(ptr++) = v>>7;
+  } else if (v < (1<<21)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = v>>14;
+  } else if (v < (1<<28)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = v>>21;
+  } else {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = (v>>21) | B;
+    *(ptr++) = v>>28;
+  }
+  return reinterpret_cast<char*>(ptr);
+}
+
+// If you know the internal layout of the std::string in use, you can
+// replace this function with one that resizes the string without
+// filling the new space with zeros (if applicable) --
+// it will be non-portable but faster.
+inline void STLStringResizeUninitialized(string* s, size_t new_size) {
+  s->resize(new_size);
+}
+
+// Return a mutable char* pointing to a string's internal buffer,
+// which may not be null-terminated. Writing through this pointer will
+// modify the string.
+//
+// string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
+// next call to a string method that invalidates iterators.
+//
+// As of 2006-04, there is no standard-blessed way of getting a
+// mutable reference to a string's internal buffer. However, issue 530
+// (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-defects.html#530)
+// proposes this as the method. It will officially be part of the standard
+// for C++0x. This should already work on all current implementations.
+inline char* string_as_array(string* str) {
+  return str->empty() ? NULL : &*str->begin();
+}
+
+}  // namespace snappy
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_

Added: couchdb/trunk/src/snappy/google-snappy/snappy-stubs-public.h.in
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/google-snappy/snappy-stubs-public.h.in?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/google-snappy/snappy-stubs-public.h.in (added)
+++ couchdb/trunk/src/snappy/google-snappy/snappy-stubs-public.h.in Mon May  2 13:28:20 2011
@@ -0,0 +1,85 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: sesse@google.com (Steinar H. Gunderson)
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various type stubs for the open-source version of Snappy.
+//
+// This file cannot include config.h, as it is included from snappy.h,
+// which is a public header. Instead, snappy-stubs-public.h is generated by
+// from snappy-stubs-public.h.in at configure time.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+
+#if @ac_cv_have_stdint_h@
+#include <stdint.h>
+#endif
+
+#if @ac_cv_have_stddef_h@
+#include <stddef.h>
+#endif
+
+#define SNAPPY_MAJOR @SNAPPY_MAJOR@
+#define SNAPPY_MINOR @SNAPPY_MINOR@
+#define SNAPPY_PATCHLEVEL @SNAPPY_PATCHLEVEL@
+#define SNAPPY_VERSION \
+    ((SNAPPY_MAJOR << 16) | (SNAPPY_MINOR << 8) | SNAPPY_PATCHLEVEL)
+
+#include <string>
+
+namespace snappy {
+
+#if @ac_cv_have_stdint_h@
+typedef int8_t int8;
+typedef uint8_t uint8;
+typedef int16_t int16;
+typedef uint16_t uint16;
+typedef int32_t int32;
+typedef uint32_t uint32;
+typedef int64_t int64;
+typedef uint64_t uint64;
+#else
+typedef signed char int8;
+typedef unsigned char uint8;
+typedef short int16;
+typedef unsigned short uint16;
+typedef int int32;
+typedef unsigned int uint32;
+typedef long long int64;
+typedef unsigned long long uint64;
+#endif
+
+typedef std::string string;
+
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);               \
+  void operator=(const TypeName&)
+
+}  // namespace snappy
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_

Added: couchdb/trunk/src/snappy/google-snappy/snappy.cc
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/google-snappy/snappy.cc?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/google-snappy/snappy.cc (added)
+++ couchdb/trunk/src/snappy/google-snappy/snappy.cc Mon May  2 13:28:20 2011
@@ -0,0 +1,1015 @@
+// Copyright 2005 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "snappy.h"
+#include "snappy-internal.h"
+#include "snappy-sinksource.h"
+
+#include <stdio.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+
+namespace snappy {
+
+// Any hash function will produce a valid compressed bitstream, but a good
+// hash function reduces the number of collisions and thus yields better
+// compression for compressible input, and more speed for incompressible
+// input. Of course, it doesn't hurt if the hash function is reasonably fast
+// either, as it gets called a lot.
+static inline uint32 HashBytes(uint32 bytes, int shift) {
+  uint32 kMul = 0x1e35a7bd;
+  return (bytes * kMul) >> shift;
+}
+static inline uint32 Hash(const char* p, int shift) {
+  return HashBytes(UNALIGNED_LOAD32(p), shift);
+}
+
+size_t MaxCompressedLength(size_t source_len) {
+  // Compressed data can be defined as:
+  //    compressed := item* literal*
+  //    item       := literal* copy
+  //
+  // The trailing literal sequence has a space blowup of at most 62/60
+  // since a literal of length 60 needs one tag byte + one extra byte
+  // for length information.
+  //
+  // Item blowup is trickier to measure.  Suppose the "copy" op copies
+  // 4 bytes of data.  Because of a special check in the encoding code,
+  // we produce a 4-byte copy only if the offset is < 65536.  Therefore
+  // the copy op takes 3 bytes to encode, and this type of item leads
+  // to at most the 62/60 blowup for representing literals.
+  //
+  // Suppose the "copy" op copies 5 bytes of data.  If the offset is big
+  // enough, it will take 5 bytes to encode the copy op.  Therefore the
+  // worst case here is a one-byte literal followed by a five-byte copy.
+  // I.e., 6 bytes of input turn into 7 bytes of "compressed" data.
+  //
+  // This last factor dominates the blowup, so the final estimate is:
+  return 32 + source_len + source_len/6;
+}
+
+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
+};
+
+// Copy "len" bytes from "src" to "op", one byte at a time.  Used for
+// handling COPY operations where the input and output regions may
+// overlap.  For example, suppose:
+//    src    == "ab"
+//    op     == src + 2
+//    len    == 20
+// After IncrementalCopy(src, op, len), the result will have
+// eleven copies of "ab"
+//    ababababababababababab
+// Note that this does not match the semantics of either memcpy()
+// or memmove().
+static inline void IncrementalCopy(const char* src, char* op, int len) {
+  DCHECK_GT(len, 0);
+  do {
+    *op++ = *src++;
+  } while (--len > 0);
+}
+
+// Equivalent to IncrementalCopy except that it can write up to ten extra
+// bytes after the end of the copy, and that it is faster.
+//
+// The main part of this loop is a simple copy of eight bytes at a time until
+// we've copied (at least) the requested amount of bytes.  However, if op and
+// src are less than eight bytes apart (indicating a repeating pattern of
+// length < 8), we first need to expand the pattern in order to get the correct
+// results. For instance, if the buffer looks like this, with the eight-byte
+// <src> and <op> patterns marked as intervals:
+//
+//    abxxxxxxxxxxxx
+//    [------]           src
+//      [------]         op
+//
+// a single eight-byte copy from <src> to <op> will repeat the pattern once,
+// after which we can move <op> two bytes without moving <src>:
+//
+//    ababxxxxxxxxxx
+//    [------]           src
+//        [------]       op
+//
+// and repeat the exercise until the two no longer overlap.
+//
+// This allows us to do very well in the special case of one single byte
+// repeated many times, without taking a big hit for more general cases.
+//
+// The worst case of extra writing past the end of the match occurs when
+// op - src == 1 and len == 1; the last copy will read from byte positions
+// [0..7] and write to [4..11], whereas it was only supposed to write to
+// position 1. Thus, ten excess bytes.
+
+namespace {
+
+const int kMaxIncrementCopyOverflow = 10;
+
+}  // namespace
+
+static inline void IncrementalCopyFastPath(const char* src, char* op, int len) {
+  while (op - src < 8) {
+    UNALIGNED_STORE64(op, UNALIGNED_LOAD64(src));
+    len -= op - src;
+    op += op - src;
+  }
+  while (len > 0) {
+    UNALIGNED_STORE64(op, UNALIGNED_LOAD64(src));
+    src += 8;
+    op += 8;
+    len -= 8;
+  }
+}
+
+static inline char* EmitLiteral(char* op,
+                                const char* literal,
+                                int len,
+                                bool allow_fast_path) {
+  int n = len - 1;      // Zero-length literals are disallowed
+  if (n < 60) {
+    // Fits in tag byte
+    *op++ = LITERAL | (n << 2);
+
+    // The vast majority of copies are below 16 bytes, for which a
+    // call to memcpy is overkill. This fast path can sometimes
+    // copy up to 15 bytes too much, but that is okay in the
+    // main loop, since we have a bit to go on for both sides:
+    //
+    //   - The input will always have kInputMarginBytes = 15 extra
+    //     available bytes, as long as we're in the main loop, and
+    //     if not, allow_fast_path = false.
+    //   - The output will always have 32 spare bytes (see
+    //     MaxCompressedLength).
+    if (allow_fast_path && len <= 16) {
+      UNALIGNED_STORE64(op, UNALIGNED_LOAD64(literal));
+      UNALIGNED_STORE64(op + 8, UNALIGNED_LOAD64(literal + 8));
+      return op + len;
+    }
+  } else {
+    // Encode in upcoming bytes
+    char* base = op;
+    int count = 0;
+    op++;
+    while (n > 0) {
+      *op++ = n & 0xff;
+      n >>= 8;
+      count++;
+    }
+    assert(count >= 1);
+    assert(count <= 4);
+    *base = LITERAL | ((59+count) << 2);
+  }
+  memcpy(op, literal, len);
+  return op + len;
+}
+
+static inline char* EmitCopyLessThan64(char* op, int offset, int len) {
+  DCHECK_LE(len, 64);
+  DCHECK_GE(len, 4);
+  DCHECK_LT(offset, 65536);
+
+  if ((len < 12) && (offset < 2048)) {
+    int len_minus_4 = len - 4;
+    assert(len_minus_4 < 8);            // Must fit in 3 bits
+    *op++ = COPY_1_BYTE_OFFSET | ((len_minus_4) << 2) | ((offset >> 8) << 5);
+    *op++ = offset & 0xff;
+  } else {
+    *op++ = COPY_2_BYTE_OFFSET | ((len-1) << 2);
+    LittleEndian::Store16(op, offset);
+    op += 2;
+  }
+  return op;
+}
+
+static inline char* EmitCopy(char* op, int offset, int len) {
+  // Emit 64 byte copies but make sure to keep at least four bytes reserved
+  while (len >= 68) {
+    op = EmitCopyLessThan64(op, offset, 64);
+    len -= 64;
+  }
+
+  // Emit an extra 60 byte copy if have too much data to fit in one copy
+  if (len > 64) {
+    op = EmitCopyLessThan64(op, offset, 60);
+    len -= 60;
+  }
+
+  // Emit remainder
+  op = EmitCopyLessThan64(op, offset, len);
+  return op;
+}
+
+
+bool GetUncompressedLength(const char* start, size_t n, size_t* result) {
+  uint32 v = 0;
+  const char* limit = start + n;
+  if (Varint::Parse32WithLimit(start, limit, &v) != NULL) {
+    *result = v;
+    return true;
+  } else {
+    return false;
+  }
+}
+
+namespace internal {
+uint16* WorkingMemory::GetHashTable(size_t input_size, int* table_size) {
+  // Use smaller hash table when input.size() is smaller, since we
+  // fill the table, incurring O(hash table size) overhead for
+  // compression, and if the input is short, we won't need that
+  // many hash table entries anyway.
+  assert(kMaxHashTableSize >= 256);
+  int htsize = 256;
+  while (htsize < kMaxHashTableSize && htsize < input_size) {
+    htsize <<= 1;
+  }
+  CHECK_EQ(0, htsize & (htsize - 1)) << ": must be power of two";
+  CHECK_LE(htsize, kMaxHashTableSize) << ": hash table too large";
+
+  uint16* table;
+  if (htsize <= ARRAYSIZE(small_table_)) {
+    table = small_table_;
+  } else {
+    if (large_table_ == NULL) {
+      large_table_ = new uint16[kMaxHashTableSize];
+    }
+    table = large_table_;
+  }
+
+  *table_size = htsize;
+  memset(table, 0, htsize * sizeof(*table));
+  return table;
+}
+}  // end namespace internal
+
+// For 0 <= offset <= 4, GetUint32AtOffset(UNALIGNED_LOAD64(p), offset) will
+// equal UNALIGNED_LOAD32(p + offset).  Motivation: On x86-64 hardware we have
+// empirically found that overlapping loads such as
+//  UNALIGNED_LOAD32(p) ... UNALIGNED_LOAD32(p+1) ... UNALIGNED_LOAD32(p+2)
+// are slower than UNALIGNED_LOAD64(p) followed by shifts and casts to uint32.
+static inline uint32 GetUint32AtOffset(uint64 v, int offset) {
+  DCHECK(0 <= offset && offset <= 4) << offset;
+  return v >> (LittleEndian::IsLittleEndian() ? 8 * offset : 32 - 8 * offset);
+}
+
+// Flat array compression that does not emit the "uncompressed length"
+// prefix. Compresses "input" string to the "*op" buffer.
+//
+// REQUIRES: "input" is at most "kBlockSize" bytes long.
+// REQUIRES: "op" points to an array of memory that is at least
+// "MaxCompressedLength(input.size())" in size.
+// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
+// REQUIRES: "table_size" is a power of two
+//
+// Returns an "end" pointer into "op" buffer.
+// "end - op" is the compressed size of "input".
+namespace internal {
+char* CompressFragment(const char* const input,
+                       const size_t input_size,
+                       char* op,
+                       uint16* table,
+                       const int table_size) {
+  // "ip" is the input pointer, and "op" is the output pointer.
+  const char* ip = input;
+  CHECK_LE(input_size, kBlockSize);
+  CHECK_EQ(table_size & (table_size - 1), 0) << ": table must be power of two";
+  const int shift = 32 - Bits::Log2Floor(table_size);
+  DCHECK_EQ(kuint32max >> shift, table_size - 1);
+  const char* ip_end = input + input_size;
+  const char* base_ip = ip;
+  // Bytes in [next_emit, ip) will be emitted as literal bytes.  Or
+  // [next_emit, ip_end) after the main loop.
+  const char* next_emit = ip;
+
+  const int kInputMarginBytes = 15;
+  if (PREDICT_TRUE(input_size >= kInputMarginBytes)) {
+    const char* ip_limit = input + input_size - kInputMarginBytes;
+
+    for (uint32 next_hash = Hash(++ip, shift); ; ) {
+      DCHECK_LT(next_emit, ip);
+      // The body of this loop calls EmitLiteral once and then EmitCopy one or
+      // more times.  (The exception is that when we're close to exhausting
+      // the input we goto emit_remainder.)
+      //
+      // In the first iteration of this loop we're just starting, so
+      // there's nothing to copy, so calling EmitLiteral once is
+      // necessary.  And we only start a new iteration when the
+      // current iteration has determined that a call to EmitLiteral will
+      // precede the next call to EmitCopy (if any).
+      //
+      // Step 1: Scan forward in the input looking for a 4-byte-long match.
+      // If we get close to exhausting the input then goto emit_remainder.
+      //
+      // Heuristic match skipping: If 32 bytes are scanned with no matches
+      // found, start looking only at every other byte. If 32 more bytes are
+      // scanned, look at every third byte, etc.. When a match is found,
+      // immediately go back to looking at every byte. This is a small loss
+      // (~5% performance, ~0.1% density) for compressible data due to more
+      // bookkeeping, but for non-compressible data (such as JPEG) it's a huge
+      // win since the compressor quickly "realizes" the data is incompressible
+      // and doesn't bother looking for matches everywhere.
+      //
+      // The "skip" variable keeps track of how many bytes there are since the
+      // last match; dividing it by 32 (ie. right-shifting by five) gives the
+      // number of bytes to move ahead for each iteration.
+      uint32 skip = 32;
+
+      const char* next_ip = ip;
+      const char* candidate;
+      do {
+        ip = next_ip;
+        uint32 hash = next_hash;
+        DCHECK_EQ(hash, Hash(ip, shift));
+        uint32 bytes_between_hash_lookups = skip++ >> 5;
+        next_ip = ip + bytes_between_hash_lookups;
+        if (PREDICT_FALSE(next_ip > ip_limit)) {
+          goto emit_remainder;
+        }
+        next_hash = Hash(next_ip, shift);
+        candidate = base_ip + table[hash];
+        DCHECK_GE(candidate, base_ip);
+        DCHECK_LT(candidate, ip);
+
+        table[hash] = ip - base_ip;
+      } while (PREDICT_TRUE(UNALIGNED_LOAD32(ip) !=
+                            UNALIGNED_LOAD32(candidate)));
+
+      // Step 2: A 4-byte match has been found.  We'll later see if more
+      // than 4 bytes match.  But, prior to the match, input
+      // bytes [next_emit, ip) are unmatched.  Emit them as "literal bytes."
+      DCHECK_LE(next_emit + 16, ip_end);
+      op = EmitLiteral(op, next_emit, ip - next_emit, true);
+
+      // Step 3: Call EmitCopy, and then see if another EmitCopy could
+      // be our next move.  Repeat until we find no match for the
+      // input immediately after what was consumed by the last EmitCopy call.
+      //
+      // If we exit this loop normally then we need to call EmitLiteral next,
+      // though we don't yet know how big the literal will be.  We handle that
+      // by proceeding to the next iteration of the main loop.  We also can exit
+      // this loop via goto if we get close to exhausting the input.
+      uint64 input_bytes = 0;
+      uint32 candidate_bytes = 0;
+
+      do {
+        // We have a 4-byte match at ip, and no need to emit any
+        // "literal bytes" prior to ip.
+        const char* base = ip;
+        int matched = 4 + FindMatchLength(candidate + 4, ip + 4, ip_end);
+        ip += matched;
+        int offset = base - candidate;
+        DCHECK_EQ(0, memcmp(base, candidate, matched));
+        op = EmitCopy(op, offset, matched);
+        // We could immediately start working at ip now, but to improve
+        // compression we first update table[Hash(ip - 1, ...)].
+        const char* insert_tail = ip - 1;
+        next_emit = ip;
+        if (PREDICT_FALSE(ip >= ip_limit)) {
+          goto emit_remainder;
+        }
+        input_bytes = UNALIGNED_LOAD64(insert_tail);
+        uint32 prev_hash = HashBytes(GetUint32AtOffset(input_bytes, 0), shift);
+        table[prev_hash] = ip - base_ip - 1;
+        uint32 cur_hash = HashBytes(GetUint32AtOffset(input_bytes, 1), shift);
+        candidate = base_ip + table[cur_hash];
+        candidate_bytes = UNALIGNED_LOAD32(candidate);
+        table[cur_hash] = ip - base_ip;
+      } while (GetUint32AtOffset(input_bytes, 1) == candidate_bytes);
+
+      next_hash = HashBytes(GetUint32AtOffset(input_bytes, 2), shift);
+      ++ip;
+    }
+  }
+
+ emit_remainder:
+  // Emit the remaining bytes as a literal
+  if (next_emit < ip_end) {
+    op = EmitLiteral(op, next_emit, ip_end - next_emit, false);
+  }
+
+  return op;
+}
+}  // end namespace internal
+
+// Signature of output types needed by decompression code.
+// The decompression code is templatized on a type that obeys this
+// signature so that we do not pay virtual function call overhead in
+// the middle of a tight decompression loop.
+//
+// class DecompressionWriter {
+//  public:
+//   // Called before decompression
+//   void SetExpectedLength(size_t length);
+//
+//   // Called after decompression
+//   bool CheckLength() const;
+//
+//   // Called repeatedly during decompression
+//   bool Append(const char* ip, uint32 length, bool allow_fast_path);
+//   bool AppendFromSelf(uint32 offset, uint32 length);
+// };
+//
+// "allow_fast_path" is a parameter that says if there is at least 16
+// readable bytes in "ip". It is currently only used by SnappyArrayWriter.
+
+// -----------------------------------------------------------------------
+// Lookup table for decompression code.  Generated by ComputeTable() below.
+// -----------------------------------------------------------------------
+
+// Mapping from i in range [0,4] to a mask to extract the bottom 8*i bits
+static const uint32 wordmask[] = {
+  0u, 0xffu, 0xffffu, 0xffffffu, 0xffffffffu
+};
+
+// 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
+};
+
+// In debug mode, allow optional computation of the table at startup.
+// Also, check that the decompression table is correct.
+#ifndef NDEBUG
+DEFINE_bool(snappy_dump_decompression_table, false,
+            "If true, we print the decompression table at startup.");
+
+static uint16 MakeEntry(unsigned int extra,
+                        unsigned int len,
+                        unsigned int copy_offset) {
+  // Check that all of the fields fit within the allocated space
+  DCHECK_EQ(extra,       extra & 0x7);          // At most 3 bits
+  DCHECK_EQ(copy_offset, copy_offset & 0x7);    // At most 3 bits
+  DCHECK_EQ(len,         len & 0x7f);           // At most 7 bits
+  return len | (copy_offset << 8) | (extra << 11);
+}
+
+static void ComputeTable() {
+  uint16 dst[256];
+
+  // Place invalid entries in all places to detect missing initialization
+  int assigned = 0;
+  for (int i = 0; i < 256; i++) {
+    dst[i] = 0xffff;
+  }
+
+  // Small LITERAL entries.  We store (len-1) in the top 6 bits.
+  for (unsigned int len = 1; len <= 60; len++) {
+    dst[LITERAL | ((len-1) << 2)] = MakeEntry(0, len, 0);
+    assigned++;
+  }
+
+  // Large LITERAL entries.  We use 60..63 in the high 6 bits to
+  // encode the number of bytes of length info that follow the opcode.
+  for (unsigned int extra_bytes = 1; extra_bytes <= 4; extra_bytes++) {
+    // We set the length field in the lookup table to 1 because extra
+    // bytes encode len-1.
+    dst[LITERAL | ((extra_bytes+59) << 2)] = MakeEntry(extra_bytes, 1, 0);
+    assigned++;
+  }
+
+  // COPY_1_BYTE_OFFSET.
+  //
+  // The tag byte in the compressed data stores len-4 in 3 bits, and
+  // offset/256 in 5 bits.  offset%256 is stored in the next byte.
+  //
+  // This format is used for length in range [4..11] and offset in
+  // range [0..2047]
+  for (unsigned int len = 4; len < 12; len++) {
+    for (unsigned int offset = 0; offset < 2048; offset += 256) {
+      dst[COPY_1_BYTE_OFFSET | ((len-4)<<2) | ((offset>>8)<<5)] =
+        MakeEntry(1, len, offset>>8);
+      assigned++;
+    }
+  }
+
+  // COPY_2_BYTE_OFFSET.
+  // Tag contains len-1 in top 6 bits, and offset in next two bytes.
+  for (unsigned int len = 1; len <= 64; len++) {
+    dst[COPY_2_BYTE_OFFSET | ((len-1)<<2)] = MakeEntry(2, len, 0);
+    assigned++;
+  }
+
+  // COPY_4_BYTE_OFFSET.
+  // Tag contents len-1 in top 6 bits, and offset in next four bytes.
+  for (unsigned int len = 1; len <= 64; len++) {
+    dst[COPY_4_BYTE_OFFSET | ((len-1)<<2)] = MakeEntry(4, len, 0);
+    assigned++;
+  }
+
+  // Check that each entry was initialized exactly once.
+  CHECK_EQ(assigned, 256);
+  for (int i = 0; i < 256; i++) {
+    CHECK_NE(dst[i], 0xffff);
+  }
+
+  if (FLAGS_snappy_dump_decompression_table) {
+    printf("static const uint16 char_table[256] = {\n  ");
+    for (int i = 0; i < 256; i++) {
+      printf("0x%04x%s",
+             dst[i],
+             ((i == 255) ? "\n" : (((i%8) == 7) ? ",\n  " : ", ")));
+    }
+    printf("};\n");
+  }
+
+  // Check that computed table matched recorded table
+  for (int i = 0; i < 256; i++) {
+    CHECK_EQ(dst[i], char_table[i]);
+  }
+}
+REGISTER_MODULE_INITIALIZER(snappy, ComputeTable());
+#endif /* !NDEBUG */
+
+// Helper class for decompression
+class SnappyDecompressor {
+ private:
+  Source*       reader_;         // Underlying source of bytes to decompress
+  const char*   ip_;             // Points to next buffered byte
+  const char*   ip_limit_;       // Points just past buffered bytes
+  uint32        peeked_;         // Bytes peeked from reader (need to skip)
+  bool          eof_;            // Hit end of input without an error?
+  char          scratch_[5];     // Temporary buffer for PeekFast() boundaries
+
+  // Ensure that all of the tag metadata for the next tag is available
+  // in [ip_..ip_limit_-1].  Also ensures that [ip,ip+4] is readable even
+  // if (ip_limit_ - ip_ < 5).
+  //
+  // Returns true on success, false on error or end of input.
+  bool RefillTag();
+
+ public:
+  explicit SnappyDecompressor(Source* reader)
+      : reader_(reader),
+        ip_(NULL),
+        ip_limit_(NULL),
+        peeked_(0),
+        eof_(false) {
+  }
+
+  ~SnappyDecompressor() {
+    // Advance past any bytes we peeked at from the reader
+    reader_->Skip(peeked_);
+  }
+
+  // Returns true iff we have hit the end of the input without an error.
+  bool eof() const {
+    return eof_;
+  }
+
+  // Read the uncompressed length stored at the start of the compressed data.
+  // On succcess, stores the length in *result and returns true.
+  // On failure, returns false.
+  bool ReadUncompressedLength(uint32* result) {
+    DCHECK(ip_ == NULL);       // Must not have read anything yet
+    // Length is encoded in 1..5 bytes
+    *result = 0;
+    uint32 shift = 0;
+    while (true) {
+      if (shift >= 32) return false;
+      size_t n;
+      const char* ip = reader_->Peek(&n);
+      if (n == 0) return false;
+      const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+      reader_->Skip(1);
+      *result |= static_cast<uint32>(c & 0x7f) << shift;
+      if (c < 128) {
+        break;
+      }
+      shift += 7;
+    }
+    return true;
+  }
+
+  // Process the next item found in the input.
+  // Returns true if successful, false on error or end of input.
+  template <class Writer>
+  bool Step(Writer* writer) {
+    const char* ip = ip_;
+    if (ip_limit_ - ip < 5) {
+      if (!RefillTag()) return false;
+      ip = ip_;
+    }
+
+    const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip++));
+    const uint32 entry = char_table[c];
+    const uint32 trailer = LittleEndian::Load32(ip) & wordmask[entry >> 11];
+    ip += entry >> 11;
+    const uint32 length = entry & 0xff;
+
+    if ((c & 0x3) == LITERAL) {
+      uint32 literal_length = length + trailer;
+      uint32 avail = ip_limit_ - ip;
+      while (avail < literal_length) {
+        bool allow_fast_path = (avail >= 16);
+        if (!writer->Append(ip, avail, allow_fast_path)) return false;
+        literal_length -= avail;
+        reader_->Skip(peeked_);
+        size_t n;
+        ip = reader_->Peek(&n);
+        avail = n;
+        peeked_ = avail;
+        if (avail == 0) return false;  // Premature end of input
+        ip_limit_ = ip + avail;
+      }
+      ip_ = ip + literal_length;
+      bool allow_fast_path = (avail >= 16);
+      return writer->Append(ip, literal_length, allow_fast_path);
+    } else {
+      ip_ = ip;
+      // copy_offset/256 is encoded in bits 8..10.  By just fetching
+      // those bits, we get copy_offset (since the bit-field starts at
+      // bit 8).
+      const uint32 copy_offset = entry & 0x700;
+      return writer->AppendFromSelf(copy_offset + trailer, length);
+    }
+  }
+};
+
+bool SnappyDecompressor::RefillTag() {
+  const char* ip = ip_;
+  if (ip == ip_limit_) {
+    // Fetch a new fragment from the reader
+    reader_->Skip(peeked_);   // All peeked bytes are used up
+    size_t n;
+    ip = reader_->Peek(&n);
+    peeked_ = n;
+    if (n == 0) {
+      eof_ = true;
+      return false;
+    }
+    ip_limit_ = ip + n;
+  }
+
+  // Read the tag character
+  DCHECK_LT(ip, ip_limit_);
+  const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+  const uint32 entry = char_table[c];
+  const uint32 needed = (entry >> 11) + 1;  // +1 byte for 'c'
+  DCHECK_LE(needed, sizeof(scratch_));
+
+  // Read more bytes from reader if needed
+  uint32 nbuf = ip_limit_ - ip;
+  if (nbuf < needed) {
+    // Stitch together bytes from ip and reader to form the word
+    // contents.  We store the needed bytes in "scratch_".  They
+    // will be consumed immediately by the caller since we do not
+    // read more than we need.
+    memmove(scratch_, ip, nbuf);
+    reader_->Skip(peeked_);  // All peeked bytes are used up
+    peeked_ = 0;
+    while (nbuf < needed) {
+      size_t length;
+      const char* src = reader_->Peek(&length);
+      if (length == 0) return false;
+      uint32 to_add = min<uint32>(needed - nbuf, length);
+      memcpy(scratch_ + nbuf, src, to_add);
+      nbuf += to_add;
+      reader_->Skip(to_add);
+    }
+    DCHECK_EQ(nbuf, needed);
+    ip_ = scratch_;
+    ip_limit_ = scratch_ + needed;
+  } else if (nbuf < 5) {
+    // Have enough bytes, but move into scratch_ so that we do not
+    // read past end of input
+    memmove(scratch_, ip, nbuf);
+    reader_->Skip(peeked_);  // All peeked bytes are used up
+    peeked_ = 0;
+    ip_ = scratch_;
+    ip_limit_ = scratch_ + nbuf;
+  } else {
+    // Pass pointer to buffer returned by reader_.
+    ip_ = ip;
+  }
+  return true;
+}
+
+template <typename Writer>
+static bool InternalUncompress(Source* r,
+                               Writer* writer,
+                               uint32 max_len) {
+  // Read the uncompressed length from the front of the compressed input
+  SnappyDecompressor decompressor(r);
+  uint32 uncompressed_len = 0;
+  if (!decompressor.ReadUncompressedLength(&uncompressed_len)) return false;
+  // Protect against possible DoS attack
+  if (static_cast<uint64>(uncompressed_len) > max_len) {
+    return false;
+  }
+
+  writer->SetExpectedLength(uncompressed_len);
+
+  // Process the entire input
+  while (decompressor.Step(writer)) { }
+  return (decompressor.eof() && writer->CheckLength());
+}
+
+bool GetUncompressedLength(Source* source, uint32* result) {
+  SnappyDecompressor decompressor(source);
+  return decompressor.ReadUncompressedLength(result);
+}
+
+size_t Compress(Source* reader, Sink* writer) {
+  size_t written = 0;
+  int N = reader->Available();
+  char ulength[Varint::kMax32];
+  char* p = Varint::Encode32(ulength, N);
+  writer->Append(ulength, p-ulength);
+  written += (p - ulength);
+
+  internal::WorkingMemory wmem;
+  char* scratch = NULL;
+  char* scratch_output = NULL;
+
+  while (N > 0) {
+    // Get next block to compress (without copying if possible)
+    size_t fragment_size;
+    const char* fragment = reader->Peek(&fragment_size);
+    DCHECK_NE(fragment_size, 0) << ": premature end of input";
+    const int num_to_read = min(N, kBlockSize);
+    size_t bytes_read = fragment_size;
+
+    int pending_advance = 0;
+    if (bytes_read >= num_to_read) {
+      // Buffer returned by reader is large enough
+      pending_advance = num_to_read;
+      fragment_size = num_to_read;
+    } else {
+      // Read into scratch buffer
+      if (scratch == NULL) {
+        // If this is the last iteration, we want to allocate N bytes
+        // of space, otherwise the max possible kBlockSize space.
+        // num_to_read contains exactly the correct value
+        scratch = new char[num_to_read];
+      }
+      memcpy(scratch, fragment, bytes_read);
+      reader->Skip(bytes_read);
+
+      while (bytes_read < num_to_read) {
+        fragment = reader->Peek(&fragment_size);
+        size_t n = min<size_t>(fragment_size, num_to_read - bytes_read);
+        memcpy(scratch + bytes_read, fragment, n);
+        bytes_read += n;
+        reader->Skip(n);
+      }
+      DCHECK_EQ(bytes_read, num_to_read);
+      fragment = scratch;
+      fragment_size = num_to_read;
+    }
+    DCHECK_EQ(fragment_size, num_to_read);
+
+    // Get encoding table for compression
+    int table_size;
+    uint16* table = wmem.GetHashTable(num_to_read, &table_size);
+
+    // Compress input_fragment and append to dest
+    const int max_output = MaxCompressedLength(num_to_read);
+
+    // Need a scratch buffer for the output, in case the byte sink doesn't
+    // have room for us directly.
+    if (scratch_output == NULL) {
+      scratch_output = new char[max_output];
+    } else {
+      // Since we encode kBlockSize regions followed by a region
+      // which is <= kBlockSize in length, a previously allocated
+      // scratch_output[] region is big enough for this iteration.
+    }
+    char* dest = writer->GetAppendBuffer(max_output, scratch_output);
+    char* end = internal::CompressFragment(fragment, fragment_size,
+                                           dest, table, table_size);
+    writer->Append(dest, end - dest);
+    written += (end - dest);
+
+    N -= num_to_read;
+    reader->Skip(pending_advance);
+  }
+
+  delete[] scratch;
+  delete[] scratch_output;
+
+  return written;
+}
+
+// -----------------------------------------------------------------------
+// Flat array interfaces
+// -----------------------------------------------------------------------
+
+// A type that writes to a flat array.
+// Note that this is not a "ByteSink", but a type that matches the
+// Writer template argument to SnappyDecompressor::Step().
+class SnappyArrayWriter {
+ private:
+  char* base_;
+  char* op_;
+  char* op_limit_;
+
+ public:
+  inline explicit SnappyArrayWriter(char* dst)
+      : base_(dst),
+        op_(dst) {
+  }
+
+  inline void SetExpectedLength(size_t len) {
+    op_limit_ = op_ + len;
+  }
+
+  inline bool CheckLength() const {
+    return op_ == op_limit_;
+  }
+
+  inline bool Append(const char* ip, uint32 len, bool allow_fast_path) {
+    char* op = op_;
+    const int space_left = op_limit_ - op;
+    if (allow_fast_path && len <= 16 && space_left >= 16) {
+      // Fast path, used for the majority (about 90%) of dynamic invocations.
+      UNALIGNED_STORE64(op, UNALIGNED_LOAD64(ip));
+      UNALIGNED_STORE64(op + 8, UNALIGNED_LOAD64(ip + 8));
+    } else {
+      if (space_left < len) {
+        return false;
+      }
+      memcpy(op, ip, len);
+    }
+    op_ = op + len;
+    return true;
+  }
+
+  inline bool AppendFromSelf(uint32 offset, uint32 len) {
+    char* op = op_;
+    const int space_left = op_limit_ - op;
+
+    if (op - base_ <= offset - 1u) {  // -1u catches offset==0
+      return false;
+    }
+    if (len <= 16 && offset >= 8 && space_left >= 16) {
+      // Fast path, used for the majority (70-80%) of dynamic invocations.
+      UNALIGNED_STORE64(op, UNALIGNED_LOAD64(op - offset));
+      UNALIGNED_STORE64(op + 8, UNALIGNED_LOAD64(op - offset + 8));
+    } else {
+      if (space_left >= len + kMaxIncrementCopyOverflow) {
+        IncrementalCopyFastPath(op - offset, op, len);
+      } else {
+        if (space_left < len) {
+          return false;
+        }
+        IncrementalCopy(op - offset, op, len);
+      }
+    }
+
+    op_ = op + len;
+    return true;
+  }
+};
+
+bool RawUncompress(const char* compressed, size_t n, char* uncompressed) {
+  ByteArraySource reader(compressed, n);
+  return RawUncompress(&reader, uncompressed);
+}
+
+bool RawUncompress(Source* compressed, char* uncompressed) {
+  SnappyArrayWriter output(uncompressed);
+  return InternalUncompress(compressed, &output, kuint32max);
+}
+
+bool Uncompress(const char* compressed, size_t n, string* uncompressed) {
+  size_t ulength;
+  if (!GetUncompressedLength(compressed, n, &ulength)) {
+    return false;
+  }
+  // Protect against possible DoS attack
+  if ((static_cast<uint64>(ulength) + uncompressed->size()) >
+      uncompressed->max_size()) {
+    return false;
+  }
+  STLStringResizeUninitialized(uncompressed, ulength);
+  return RawUncompress(compressed, n, string_as_array(uncompressed));
+}
+
+
+// A Writer that drops everything on the floor and just does validation
+class SnappyDecompressionValidator {
+ private:
+  size_t expected_;
+  size_t produced_;
+
+ public:
+  inline SnappyDecompressionValidator() : produced_(0) { }
+  inline void SetExpectedLength(size_t len) {
+    expected_ = len;
+  }
+  inline bool CheckLength() const {
+    return expected_ == produced_;
+  }
+  inline bool Append(const char* ip, uint32 len, bool allow_fast_path) {
+    produced_ += len;
+    return produced_ <= expected_;
+  }
+  inline bool AppendFromSelf(uint32 offset, uint32 len) {
+    if (produced_ <= offset - 1u) return false;  // -1u catches offset==0
+    produced_ += len;
+    return produced_ <= expected_;
+  }
+};
+
+bool IsValidCompressedBuffer(const char* compressed, size_t n) {
+  ByteArraySource reader(compressed, n);
+  SnappyDecompressionValidator writer;
+  return InternalUncompress(&reader, &writer, kuint32max);
+}
+
+void RawCompress(const char* input,
+                 size_t input_length,
+                 char* compressed,
+                 size_t* compressed_length) {
+  ByteArraySource reader(input, input_length);
+  UncheckedByteArraySink writer(compressed);
+  Compress(&reader, &writer);
+
+  // Compute how many bytes were added
+  *compressed_length = (writer.CurrentDestination() - compressed);
+}
+
+size_t Compress(const char* input, size_t input_length, string* compressed) {
+  // Pre-grow the buffer to the max length of the compressed output
+  compressed->resize(MaxCompressedLength(input_length));
+
+  size_t compressed_length;
+  RawCompress(input, input_length, string_as_array(compressed),
+              &compressed_length);
+  compressed->resize(compressed_length);
+  return compressed_length;
+}
+
+
+} // end namespace snappy
+

Added: couchdb/trunk/src/snappy/google-snappy/snappy.h
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/google-snappy/snappy.h?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/google-snappy/snappy.h (added)
+++ couchdb/trunk/src/snappy/google-snappy/snappy.h Mon May  2 13:28:20 2011
@@ -0,0 +1,155 @@
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// A light-weight compression algorithm.  It is designed for speed of
+// compression and decompression, rather than for the utmost in space
+// savings.
+//
+// For getting better compression ratios when you are compressing data
+// with long repeated sequences or compressing data that is similar to
+// other data, while still compressing fast, you might look at first
+// using BMDiff and then compressing the output of BMDiff with
+// Snappy.
+
+#ifndef UTIL_SNAPPY_SNAPPY_H__
+#define UTIL_SNAPPY_SNAPPY_H__
+
+#include <stddef.h>
+#include <string>
+
+#include "snappy-stubs-public.h"
+
+namespace snappy {
+  class Source;
+  class Sink;
+
+  // ------------------------------------------------------------------------
+  // Generic compression/decompression routines.
+  // ------------------------------------------------------------------------
+
+  // Compress the bytes read from "*source" and append to "*sink". Return the
+  // number of bytes written.
+  size_t Compress(Source* source, Sink* sink);
+
+  bool GetUncompressedLength(Source* source, uint32* result);
+
+  // ------------------------------------------------------------------------
+  // Higher-level string based routines (should be sufficient for most users)
+  // ------------------------------------------------------------------------
+
+  // Sets "*output" to the compressed version of "input[0,input_length-1]".
+  // Original contents of *output are lost.
+  //
+  // REQUIRES: "input[]" is not an alias of "*output".
+  size_t Compress(const char* input, size_t input_length, string* output);
+
+  // Decompresses "compressed[0,compressed_length-1]" to "*uncompressed".
+  // Original contents of "*uncompressed" are lost.
+  //
+  // REQUIRES: "compressed[]" is not an alias of "*uncompressed".
+  //
+  // returns false if the message is corrupted and could not be decompressed
+  bool Uncompress(const char* compressed, size_t compressed_length,
+                  string* uncompressed);
+
+
+  // ------------------------------------------------------------------------
+  // Lower-level character array based routines.  May be useful for
+  // efficiency reasons in certain circumstances.
+  // ------------------------------------------------------------------------
+
+  // REQUIRES: "compressed" must point to an area of memory that is at
+  // least "MaxCompressedLength(input_length)" bytes in length.
+  //
+  // Takes the data stored in "input[0..input_length]" and stores
+  // it in the array pointed to by "compressed".
+  //
+  // "*compressed_length" is set to the length of the compressed output.
+  //
+  // Example:
+  //    char* output = new char[snappy::MaxCompressedLength(input_length)];
+  //    size_t output_length;
+  //    RawCompress(input, input_length, output, &output_length);
+  //    ... Process(output, output_length) ...
+  //    delete [] output;
+  void RawCompress(const char* input,
+                   size_t input_length,
+                   char* compressed,
+                   size_t* compressed_length);
+
+  // Given data in "compressed[0..compressed_length-1]" generated by
+  // calling the Snappy::Compress routine, this routine
+  // stores the uncompressed data to
+  //    uncompressed[0..GetUncompressedLength(compressed)-1]
+  // returns false if the message is corrupted and could not be decrypted
+  bool RawUncompress(const char* compressed, size_t compressed_length,
+                     char* uncompressed);
+
+  // Given data from the byte source 'compressed' generated by calling
+  // the Snappy::Compress routine, this routine stores the uncompressed
+  // data to
+  //    uncompressed[0..GetUncompressedLength(compressed,compressed_length)-1]
+  // returns false if the message is corrupted and could not be decrypted
+  bool RawUncompress(Source* compressed, char* uncompressed);
+
+  // Returns the maximal size of the compressed representation of
+  // input data that is "source_bytes" bytes in length;
+  size_t MaxCompressedLength(size_t source_bytes);
+
+  // REQUIRES: "compressed[]" was produced by RawCompress() or Compress()
+  // Returns true and stores the length of the uncompressed data in
+  // *result normally.  Returns false on parsing error.
+  // This operation takes O(1) time.
+  bool GetUncompressedLength(const char* compressed, size_t compressed_length,
+                             size_t* result);
+
+  // Returns true iff the contents of "compressed[]" can be uncompressed
+  // successfully.  Does not return the uncompressed data.  Takes
+  // time proportional to compressed_length, but is usually at least
+  // a factor of four faster than actual decompression.
+  bool IsValidCompressedBuffer(const char* compressed,
+                               size_t compressed_length);
+
+  // *** DO NOT CHANGE THE VALUE OF kBlockSize ***
+  //
+  // New Compression code chops up the input into blocks of at most
+  // the following size.  This ensures that back-references in the
+  // output never cross kBlockSize block boundaries.  This can be
+  // helpful in implementing blocked decompression.  However the
+  // decompression code should not rely on this guarantee since older
+  // compression code may not obey it.
+  static const int kBlockLog = 15;
+  static const int kBlockSize = 1 << kBlockLog;
+
+  static const int kMaxHashTableBits = 14;
+  static const int kMaxHashTableSize = 1 << kMaxHashTableBits;
+
+}  // end namespace snappy
+
+
+#endif  // UTIL_SNAPPY_SNAPPY_H__

Added: couchdb/trunk/src/snappy/snappy.app.in
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/snappy.app.in?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/snappy.app.in (added)
+++ couchdb/trunk/src/snappy/snappy.app.in Mon May  2 13:28:20 2011
@@ -0,0 +1,12 @@
+{application, snappy,
+ [
+  {description, "snappy compressor/decompressor Erlang NIF wrapper"},
+  {vsn, "1.0.1"},
+  {registered, []},
+  {applications, [
+                  kernel,
+                  stdlib
+                 ]},
+  {env, []},
+  {modules, [snappy]}
+ ]}.

Added: couchdb/trunk/src/snappy/snappy.erl
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/snappy.erl?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/snappy.erl (added)
+++ couchdb/trunk/src/snappy/snappy.erl Mon May  2 13:28:20 2011
@@ -0,0 +1,57 @@
+%% Copyright 2011,  Filipe David Manana  <fdmanana@apache.org>
+%% Web:  http://github.com/fdmanana/snappy-erlang-nif
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License"); you may not
+%% use this file except in compliance with the License. You may obtain a copy of
+%% the License at
+%%
+%%  http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+%% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+%% License for the specific language governing permissions and limitations under
+%% the License.
+
+-module(snappy).
+
+-export([compress/1, decompress/1]).
+-export([get_uncompressed_length/1]).
+-export([is_valid_compressed_buffer/1]).
+
+-on_load(init/0).
+
+
+init() ->
+    SoName = case code:priv_dir(?MODULE) of
+    {error, bad_name} ->
+        case filelib:is_dir(filename:join(["..", "priv"])) of
+        true ->
+            filename:join(["..", "priv", "snappy_nif"]);
+        false ->
+            filename:join(["priv", "snappy_nif"])
+        end;
+    Dir ->
+        filename:join(Dir, "snappy_nif")
+    end,
+    (catch erlang:load_nif(SoName, 0)),
+    case erlang:system_info(otp_release) of
+    "R13B03" -> true;
+    _ -> ok
+    end.
+
+
+compress(_IoList) ->
+    exit(snappy_nif_not_loaded).
+
+
+decompress(_IoList) ->
+    exit(snappy_nif_not_loaded).
+
+
+get_uncompressed_length(_IoList) ->
+    exit(snappy_nif_not_loaded).
+
+
+is_valid_compressed_buffer(_IoList) ->
+    exit(snappy_nif_not_loaded).

Added: couchdb/trunk/src/snappy/snappy_nif.cc
URL: http://svn.apache.org/viewvc/couchdb/trunk/src/snappy/snappy_nif.cc?rev=1098558&view=auto
==============================================================================
--- couchdb/trunk/src/snappy/snappy_nif.cc (added)
+++ couchdb/trunk/src/snappy/snappy_nif.cc Mon May  2 13:28:20 2011
@@ -0,0 +1,231 @@
+/**
+ * Copyright 2011,  Filipe David Manana  <fdmanana@apache.org>
+ * Web:  http://github.com/fdmanana/snappy-erlang-nif
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ **/
+
+#include <iostream>
+#include <cstring>
+
+#include "erl_nif_compat.h"
+#include "google-snappy/snappy.h"
+#include "google-snappy/snappy-sinksource.h"
+
+#ifdef OTP_R13B03
+#error OTP R13B03 not supported. Upgrade to R13B04 or later.
+#endif
+
+
+class SnappyNifSink : public snappy::Sink {
+public:
+    SnappyNifSink(ErlNifEnv* e) : env(e), length(0)  {
+        if (!enif_alloc_binary_compat(env, 0, &bin)) {
+            enif_release_binary_compat(env, &bin);
+            throw std::bad_alloc();
+        }
+    }
+
+    void Append(const char *data, size_t n) {
+        if (data != reinterpret_cast<const char *>(bin.data + length)) {
+            memcpy(bin.data + length, data, n);
+        }
+        length += n;
+    }
+
+    char* GetAppendBuffer(size_t len, char* scratch) {
+        if ((length + len) > bin.size) {
+            size_t sz = (len * 4) < 8192 ? 8192 : (len * 4);
+
+            if (!enif_realloc_binary_compat(env, &bin, bin.size + sz)) {
+                enif_release_binary_compat(env, &bin);
+                throw std::bad_alloc();
+            }
+        }
+
+        return reinterpret_cast<char *>(bin.data + length);
+    }
+
+    ErlNifBinary& getBin() {
+        if (bin.size > length) {
+            if (!enif_realloc_binary_compat(env, &bin, length)) {
+                // shouldn't happen
+                enif_release_binary_compat(env, &bin);
+                throw std::bad_alloc();
+            }
+        }
+        return bin;
+    }
+
+private:
+    ErlNifEnv* env;
+    ErlNifBinary bin;
+    size_t length;
+};
+
+
+extern "C" {
+
+    ERL_NIF_TERM snappy_compress(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
+        ErlNifBinary input;
+
+        if (!enif_inspect_iolist_as_binary(env, argv[0], &input)) {
+            return enif_make_badarg(env);
+        }
+
+        try {
+            snappy::ByteArraySource source(reinterpret_cast<const char *>(input.data),
+                                           input.size);
+            SnappyNifSink sink(env);
+
+            snappy::Compress(&source, &sink);
+
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "ok"),
+                                   enif_make_binary(env, &sink.getBin()));
+        } catch(std::bad_alloc e) {
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "error"),
+                                   enif_make_atom(env, "insufficient_memory"));
+        } catch(...) {
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "error"),
+                                   enif_make_atom(env, "unknown"));
+        }
+    }
+
+
+    ERL_NIF_TERM snappy_decompress(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
+        ErlNifBinary input;
+
+        if (!enif_inspect_iolist_as_binary(env, argv[0], &input)) {
+            return enif_make_badarg(env);
+        }
+
+        try {
+            size_t len = -1;
+            bool isCompressed = snappy::GetUncompressedLength(
+                reinterpret_cast<const char *>(input.data), input.size, &len);
+
+            if (!isCompressed) {
+                return enif_make_tuple(env, 2,
+                                       enif_make_atom(env, "error"),
+                                       enif_make_atom(env, "not_compressed_data"));
+            }
+
+            ErlNifBinary retBin;
+
+            if (!enif_alloc_binary_compat(env, len, &retBin)) {
+                return enif_make_tuple(env, 2,
+                                       enif_make_atom(env, "error"),
+                                       enif_make_atom(env, "insufficient_memory"));
+            }
+
+            bool valid = snappy::RawUncompress(reinterpret_cast<const char *>(input.data),
+                                               input.size,
+                                               reinterpret_cast<char *>(retBin.data));
+
+            if (!valid) {
+                return enif_make_tuple(env, 2,
+                                       enif_make_atom(env, "error"),
+                                       enif_make_atom(env, "corrupted_data"));
+            }
+
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "ok"),
+                                   enif_make_binary(env, &retBin));
+        } catch(...) {
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "error"),
+                                   enif_make_atom(env, "unknown"));
+        }
+    }
+
+
+    ERL_NIF_TERM snappy_get_uncompressed_length(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
+        ErlNifBinary input;
+
+        if (!enif_inspect_iolist_as_binary(env, argv[0], &input)) {
+            return enif_make_badarg(env);
+        }
+
+        try {
+            size_t len = -1;
+            bool isCompressed = snappy::GetUncompressedLength(
+                reinterpret_cast<const char *>(input.data), input.size, &len);
+
+            if (isCompressed) {
+                return enif_make_tuple(env, 2,
+                                       enif_make_atom(env, "ok"),
+                                       enif_make_ulong(env, len));
+            } else {
+                return enif_make_tuple(env, 2,
+                                       enif_make_atom(env, "error"),
+                                       enif_make_atom(env, "not_compressed_data"));
+            }
+        } catch(...) {
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "error"),
+                                   enif_make_atom(env, "unknown"));
+        }
+    }
+
+
+    ERL_NIF_TERM snappy_is_valid_compressed_buffer(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
+        ErlNifBinary input;
+
+        if (!enif_inspect_iolist_as_binary(env, argv[0], &input)) {
+            return enif_make_badarg(env);
+        }
+
+        try {
+            bool valid = snappy::IsValidCompressedBuffer(
+                reinterpret_cast<const char *>(input.data), input.size);
+
+            if (valid) {
+                return enif_make_atom(env, "true");
+            } else {
+                return enif_make_atom(env, "false");
+            }
+        } catch(...) {
+            return enif_make_tuple(env, 2,
+                                   enif_make_atom(env, "error"),
+                                   enif_make_atom(env, "unknown"));
+        }
+    }
+
+
+
+    int on_load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM info) {
+        return 0;
+    }
+
+
+    int on_reload(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM info) {
+        return 0;
+    }
+
+    int on_upgrade(ErlNifEnv* env, void** priv_data, void** old_data, ERL_NIF_TERM info) {
+        return 0;
+    }
+
+
+    static ErlNifFunc nif_functions[] = {
+        {"compress", 1, snappy_compress},
+        {"decompress", 1, snappy_decompress},
+        {"get_uncompressed_length", 1, snappy_get_uncompressed_length},
+        {"is_valid_compressed_buffer", 1, snappy_is_valid_compressed_buffer}
+    };
+
+    ERL_NIF_INIT(snappy, nif_functions, &on_load, &on_reload, &on_upgrade, NULL);
+}

Modified: couchdb/trunk/test/etap/010-file-basics.t
URL: http://svn.apache.org/viewvc/couchdb/trunk/test/etap/010-file-basics.t?rev=1098558&r1=1098557&r2=1098558&view=diff
==============================================================================
--- couchdb/trunk/test/etap/010-file-basics.t (original)
+++ couchdb/trunk/test/etap/010-file-basics.t Mon May  2 13:28:20 2011
@@ -64,7 +64,7 @@ test() ->
     etap:is({ok, <<"fancy!">>}, couch_file:pread_binary(Fd, Size),
         "Reading back the binary returns what we wrote: <<\"fancy\">>."),
 
-    etap:is({ok, <<131, 100, 0, 3, 102, 111, 111>>},
+    etap:is({ok, couch_compress:compress(foo, snappy)},
         couch_file:pread_binary(Fd, 0),
         "Reading a binary at a term position returns the term as binary."
     ),

Modified: couchdb/trunk/test/etap/020-btree-basics.t
URL: http://svn.apache.org/viewvc/couchdb/trunk/test/etap/020-btree-basics.t?rev=1098558&r1=1098557&r2=1098558&view=diff
==============================================================================
--- couchdb/trunk/test/etap/020-btree-basics.t (original)
+++ couchdb/trunk/test/etap/020-btree-basics.t Mon May  2 13:28:20 2011
@@ -17,7 +17,15 @@
 filename() -> test_util:build_file("test/etap/temp.020").
 rows() -> 250.
 
--record(btree, {fd, root, extract_kv, assemble_kv, less, reduce}).
+-record(btree, {
+    fd,
+    root,
+    extract_kv,
+    assemble_kv,
+    less,
+    reduce,
+    compression
+}).
 
 main(_) ->
     test_util:init_code_path(),
@@ -52,7 +60,7 @@ test_kvs(KeyValues) ->
     Keys = [K || {K, _} <- KeyValues],
 
     {ok, Fd} = couch_file:open(filename(), [create,overwrite]),
-    {ok, Btree} = couch_btree:open(nil, Fd),
+    {ok, Btree} = couch_btree:open(nil, Fd, [{compression, none}]),
     etap:ok(is_record(Btree, btree), "Created btree is really a btree record"),
     etap:is(Btree#btree.fd, Fd, "Btree#btree.fd is set correctly."),
     etap:is(Btree#btree.root, nil, "Btree#btree.root is set correctly."),

Modified: couchdb/trunk/test/etap/200-view-group-no-db-leaks.t
URL: http://svn.apache.org/viewvc/couchdb/trunk/test/etap/200-view-group-no-db-leaks.t?rev=1098558&r1=1098557&r2=1098558&view=diff
==============================================================================
--- couchdb/trunk/test/etap/200-view-group-no-db-leaks.t (original)
+++ couchdb/trunk/test/etap/200-view-group-no-db-leaks.t Mon May  2 13:28:20 2011
@@ -57,7 +57,8 @@
     waiting_delayed_commit = nil,
     revs_limit = 1000,
     fsync_options = [],
-    options = []
+    options = [],
+    compression
 }).
 
 test_db_name() -> <<"couch_test_view_group_db_leaks">>.

Modified: couchdb/trunk/test/etap/test_util.erl.in
URL: http://svn.apache.org/viewvc/couchdb/trunk/test/etap/test_util.erl.in?rev=1098558&r1=1098557&r2=1098558&view=diff
==============================================================================
--- couchdb/trunk/test/etap/test_util.erl.in (original)
+++ couchdb/trunk/test/etap/test_util.erl.in Mon May  2 13:28:20 2011
@@ -22,7 +22,8 @@ builddir() ->
     "@abs_top_builddir@".
 
 init_code_path() ->
-    Paths = ["etap", "couchdb", "ejson", "erlang-oauth", "ibrowse", "mochiweb"],
+    Paths = ["etap", "couchdb", "ejson", "erlang-oauth", "ibrowse", "mochiweb",
+             "snappy"],
     lists:foreach(fun(Name) ->
         code:add_patha(filename:join([builddir(), "src", Name]))
     end, Paths).

Modified: couchdb/trunk/utils/Makefile.am
URL: http://svn.apache.org/viewvc/couchdb/trunk/utils/Makefile.am?rev=1098558&r1=1098557&r2=1098558&view=diff
==============================================================================
--- couchdb/trunk/utils/Makefile.am (original)
+++ couchdb/trunk/utils/Makefile.am Mon May  2 13:28:20 2011
@@ -28,7 +28,8 @@ run: ../bin/couchdb.tpl
 			-pa $(abs_top_builddir)\/src\/ejson \
 			-pa $(abs_top_builddir)\/src\/erlang-oauth \
 			-pa $(abs_top_builddir)\/src\/ibrowse \
-			-pa $(abs_top_builddir)\/src\/mochiweb|g" \
+			-pa $(abs_top_builddir)\/src\/mochiweb \
+			-pa $(abs_top_builddir)\/src\/snappy|g" \
 	    -e "s|%localconfdir%|$(abs_top_builddir)/etc/couchdb|g" \
 	    -e "s|%localstatelogdir%|$(abs_top_builddir)/tmp/log|g" \
 	    -e "s|%localstatelibdir%|$(abs_top_builddir)/tmp/lib|g" \