Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 966 insertions, 0 deletions

diff --git a/other-licenses/snappy/src/snappy_unittest.cc b/other-licenses/snappy/src/snappy_unittest.cc
new file mode 100644
index 0000000000..7a85635d73
--- /dev/null
+++ b/other-licenses/snappy/src/snappy_unittest.cc
@@ -0,0 +1,966 @@
+// 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.
+
+#include <algorithm>
+#include <cmath>
+#include <cstdlib>
+#include <random>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "snappy-test.h"
+
+#include "gtest/gtest.h"
+
+#include "snappy-internal.h"
+#include "snappy-sinksource.h"
+#include "snappy.h"
+#include "snappy_test_data.h"
+
+SNAPPY_FLAG(bool, snappy_dump_decompression_table, false,
+            "If true, we print the decompression table during tests.");
+
+namespace snappy {
+
+namespace {
+
+#if defined(HAVE_FUNC_MMAP) && defined(HAVE_FUNC_SYSCONF)
+
+// To test against code that reads beyond its input, this class copies a
+// string to a newly allocated group of pages, the last of which
+// is made unreadable via mprotect. Note that we need to allocate the
+// memory with mmap(), as POSIX allows mprotect() only on memory allocated
+// with mmap(), and some malloc/posix_memalign implementations expect to
+// be able to read previously allocated memory while doing heap allocations.
+class DataEndingAtUnreadablePage {
+ public:
+  explicit DataEndingAtUnreadablePage(const std::string& s) {
+    const size_t page_size = sysconf(_SC_PAGESIZE);
+    const size_t size = s.size();
+    // Round up space for string to a multiple of page_size.
+    size_t space_for_string = (size + page_size - 1) & ~(page_size - 1);
+    alloc_size_ = space_for_string + page_size;
+    mem_ = mmap(NULL, alloc_size_,
+                PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    CHECK_NE(MAP_FAILED, mem_);
+    protected_page_ = reinterpret_cast<char*>(mem_) + space_for_string;
+    char* dst = protected_page_ - size;
+    std::memcpy(dst, s.data(), size);
+    data_ = dst;
+    size_ = size;
+    // Make guard page unreadable.
+    CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_NONE));
+  }
+
+  ~DataEndingAtUnreadablePage() {
+    const size_t page_size = sysconf(_SC_PAGESIZE);
+    // Undo the mprotect.
+    CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_READ|PROT_WRITE));
+    CHECK_EQ(0, munmap(mem_, alloc_size_));
+  }
+
+  const char* data() const { return data_; }
+  size_t size() const { return size_; }
+
+ private:
+  size_t alloc_size_;
+  void* mem_;
+  char* protected_page_;
+  const char* data_;
+  size_t size_;
+};
+
+#else  // defined(HAVE_FUNC_MMAP) && defined(HAVE_FUNC_SYSCONF)
+
+// Fallback for systems without mmap.
+using DataEndingAtUnreadablePage = std::string;
+
+#endif
+
+int VerifyString(const std::string& input) {
+  std::string compressed;
+  DataEndingAtUnreadablePage i(input);
+  const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+  CHECK_EQ(written, compressed.size());
+  CHECK_LE(compressed.size(),
+           snappy::MaxCompressedLength(input.size()));
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+  std::string uncompressed;
+  DataEndingAtUnreadablePage c(compressed);
+  CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+  CHECK_EQ(uncompressed, input);
+  return uncompressed.size();
+}
+
+void VerifyStringSink(const std::string& input) {
+  std::string compressed;
+  DataEndingAtUnreadablePage i(input);
+  const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+  CHECK_EQ(written, compressed.size());
+  CHECK_LE(compressed.size(),
+           snappy::MaxCompressedLength(input.size()));
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+  std::string uncompressed;
+  uncompressed.resize(input.size());
+  snappy::UncheckedByteArraySink sink(string_as_array(&uncompressed));
+  DataEndingAtUnreadablePage c(compressed);
+  snappy::ByteArraySource source(c.data(), c.size());
+  CHECK(snappy::Uncompress(&source, &sink));
+  CHECK_EQ(uncompressed, input);
+}
+
+void VerifyIOVec(const std::string& input) {
+  std::string compressed;
+  DataEndingAtUnreadablePage i(input);
+  const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+  CHECK_EQ(written, compressed.size());
+  CHECK_LE(compressed.size(),
+           snappy::MaxCompressedLength(input.size()));
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+  // Try uncompressing into an iovec containing a random number of entries
+  // ranging from 1 to 10.
+  char* buf = new char[input.size()];
+  std::minstd_rand0 rng(input.size());
+  std::uniform_int_distribution<size_t> uniform_1_to_10(1, 10);
+  size_t num = uniform_1_to_10(rng);
+  if (input.size() < num) {
+    num = input.size();
+  }
+  struct iovec* iov = new iovec[num];
+  size_t used_so_far = 0;
+  std::bernoulli_distribution one_in_five(1.0 / 5);
+  for (size_t i = 0; i < num; ++i) {
+    assert(used_so_far < input.size());
+    iov[i].iov_base = buf + used_so_far;
+    if (i == num - 1) {
+      iov[i].iov_len = input.size() - used_so_far;
+    } else {
+      // Randomly choose to insert a 0 byte entry.
+      if (one_in_five(rng)) {
+        iov[i].iov_len = 0;
+      } else {
+        std::uniform_int_distribution<size_t> uniform_not_used_so_far(
+            0, input.size() - used_so_far - 1);
+        iov[i].iov_len = uniform_not_used_so_far(rng);
+      }
+    }
+    used_so_far += iov[i].iov_len;
+  }
+  CHECK(snappy::RawUncompressToIOVec(
+      compressed.data(), compressed.size(), iov, num));
+  CHECK(!memcmp(buf, input.data(), input.size()));
+  delete[] iov;
+  delete[] buf;
+}
+
+// Test that data compressed by a compressor that does not
+// obey block sizes is uncompressed properly.
+void VerifyNonBlockedCompression(const std::string& input) {
+  if (input.length() > snappy::kBlockSize) {
+    // We cannot test larger blocks than the maximum block size, obviously.
+    return;
+  }
+
+  std::string prefix;
+  Varint::Append32(&prefix, input.size());
+
+  // Setup compression table
+  snappy::internal::WorkingMemory wmem(input.size());
+  int table_size;
+  uint16_t* table = wmem.GetHashTable(input.size(), &table_size);
+
+  // Compress entire input in one shot
+  std::string compressed;
+  compressed += prefix;
+  compressed.resize(prefix.size()+snappy::MaxCompressedLength(input.size()));
+  char* dest = string_as_array(&compressed) + prefix.size();
+  char* end = snappy::internal::CompressFragment(input.data(), input.size(),
+                                                dest, table, table_size);
+  compressed.resize(end - compressed.data());
+
+  // Uncompress into std::string
+  std::string uncomp_str;
+  CHECK(snappy::Uncompress(compressed.data(), compressed.size(), &uncomp_str));
+  CHECK_EQ(uncomp_str, input);
+
+  // Uncompress using source/sink
+  std::string uncomp_str2;
+  uncomp_str2.resize(input.size());
+  snappy::UncheckedByteArraySink sink(string_as_array(&uncomp_str2));
+  snappy::ByteArraySource source(compressed.data(), compressed.size());
+  CHECK(snappy::Uncompress(&source, &sink));
+  CHECK_EQ(uncomp_str2, input);
+
+  // Uncompress into iovec
+  {
+    static const int kNumBlocks = 10;
+    struct iovec vec[kNumBlocks];
+    const int block_size = 1 + input.size() / kNumBlocks;
+    std::string iovec_data(block_size * kNumBlocks, 'x');
+    for (int i = 0; i < kNumBlocks; ++i) {
+      vec[i].iov_base = string_as_array(&iovec_data) + i * block_size;
+      vec[i].iov_len = block_size;
+    }
+    CHECK(snappy::RawUncompressToIOVec(compressed.data(), compressed.size(),
+                                       vec, kNumBlocks));
+    CHECK_EQ(std::string(iovec_data.data(), input.size()), input);
+  }
+}
+
+// Expand the input so that it is at least K times as big as block size
+std::string Expand(const std::string& input) {
+  static const int K = 3;
+  std::string data = input;
+  while (data.size() < K * snappy::kBlockSize) {
+    data += input;
+  }
+  return data;
+}
+
+int Verify(const std::string& input) {
+  VLOG(1) << "Verifying input of size " << input.size();
+
+  // Compress using string based routines
+  const int result = VerifyString(input);
+
+  // Verify using sink based routines
+  VerifyStringSink(input);
+
+  VerifyNonBlockedCompression(input);
+  VerifyIOVec(input);
+  if (!input.empty()) {
+    const std::string expanded = Expand(input);
+    VerifyNonBlockedCompression(expanded);
+    VerifyIOVec(input);
+  }
+
+  return result;
+}
+
+bool IsValidCompressedBuffer(const std::string& c) {
+  return snappy::IsValidCompressedBuffer(c.data(), c.size());
+}
+bool Uncompress(const std::string& c, std::string* u) {
+  return snappy::Uncompress(c.data(), c.size(), u);
+}
+
+// This test checks to ensure that snappy doesn't coredump if it gets
+// corrupted data.
+TEST(CorruptedTest, VerifyCorrupted) {
+  std::string source = "making sure we don't crash with corrupted input";
+  VLOG(1) << source;
+  std::string dest;
+  std::string uncmp;
+  snappy::Compress(source.data(), source.size(), &dest);
+
+  // Mess around with the data. It's hard to simulate all possible
+  // corruptions; this is just one example ...
+  CHECK_GT(dest.size(), 3);
+  dest[1]--;
+  dest[3]++;
+  // this really ought to fail.
+  CHECK(!IsValidCompressedBuffer(dest));
+  CHECK(!Uncompress(dest, &uncmp));
+
+  // This is testing for a security bug - a buffer that decompresses to 100k
+  // but we lie in the snappy header and only reserve 0 bytes of memory :)
+  source.resize(100000);
+  for (char& source_char : source) {
+    source_char = 'A';
+  }
+  snappy::Compress(source.data(), source.size(), &dest);
+  dest[0] = dest[1] = dest[2] = dest[3] = 0;
+  CHECK(!IsValidCompressedBuffer(dest));
+  CHECK(!Uncompress(dest, &uncmp));
+
+  if (sizeof(void *) == 4) {
+    // Another security check; check a crazy big length can't DoS us with an
+    // over-allocation.
+    // Currently this is done only for 32-bit builds.  On 64-bit builds,
+    // where 3 GB might be an acceptable allocation size, Uncompress()
+    // attempts to decompress, and sometimes causes the test to run out of
+    // memory.
+    dest[0] = dest[1] = dest[2] = dest[3] = '\xff';
+    // This decodes to a really large size, i.e., about 3 GB.
+    dest[4] = 'k';
+    CHECK(!IsValidCompressedBuffer(dest));
+    CHECK(!Uncompress(dest, &uncmp));
+  } else {
+    LOG(WARNING) << "Crazy decompression lengths not checked on 64-bit build";
+  }
+
+  // This decodes to about 2 MB; much smaller, but should still fail.
+  dest[0] = dest[1] = dest[2] = '\xff';
+  dest[3] = 0x00;
+  CHECK(!IsValidCompressedBuffer(dest));
+  CHECK(!Uncompress(dest, &uncmp));
+
+  // try reading stuff in from a bad file.
+  for (int i = 1; i <= 3; ++i) {
+    std::string data =
+        ReadTestDataFile(StrFormat("baddata%d.snappy", i).c_str(), 0);
+    std::string uncmp;
+    // check that we don't return a crazy length
+    size_t ulen;
+    CHECK(!snappy::GetUncompressedLength(data.data(), data.size(), &ulen)
+          || (ulen < (1<<20)));
+    uint32_t ulen2;
+    snappy::ByteArraySource source(data.data(), data.size());
+    CHECK(!snappy::GetUncompressedLength(&source, &ulen2) ||
+          (ulen2 < (1<<20)));
+    CHECK(!IsValidCompressedBuffer(data));
+    CHECK(!Uncompress(data, &uncmp));
+  }
+}
+
+// Helper routines to construct arbitrary compressed strings.
+// These mirror the compression code in snappy.cc, but are copied
+// here so that we can bypass some limitations in the how snappy.cc
+// invokes these routines.
+void AppendLiteral(std::string* dst, const std::string& literal) {
+  if (literal.empty()) return;
+  int n = literal.size() - 1;
+  if (n < 60) {
+    // Fit length in tag byte
+    dst->push_back(0 | (n << 2));
+  } else {
+    // Encode in upcoming bytes
+    char number[4];
+    int count = 0;
+    while (n > 0) {
+      number[count++] = n & 0xff;
+      n >>= 8;
+    }
+    dst->push_back(0 | ((59+count) << 2));
+    *dst += std::string(number, count);
+  }
+  *dst += literal;
+}
+
+void AppendCopy(std::string* dst, int offset, int length) {
+  while (length > 0) {
+    // Figure out how much to copy in one shot
+    int to_copy;
+    if (length >= 68) {
+      to_copy = 64;
+    } else if (length > 64) {
+      to_copy = 60;
+    } else {
+      to_copy = length;
+    }
+    length -= to_copy;
+
+    if ((to_copy >= 4) && (to_copy < 12) && (offset < 2048)) {
+      assert(to_copy-4 < 8);            // Must fit in 3 bits
+      dst->push_back(1 | ((to_copy-4) << 2) | ((offset >> 8) << 5));
+      dst->push_back(offset & 0xff);
+    } else if (offset < 65536) {
+      dst->push_back(2 | ((to_copy-1) << 2));
+      dst->push_back(offset & 0xff);
+      dst->push_back(offset >> 8);
+    } else {
+      dst->push_back(3 | ((to_copy-1) << 2));
+      dst->push_back(offset & 0xff);
+      dst->push_back((offset >> 8) & 0xff);
+      dst->push_back((offset >> 16) & 0xff);
+      dst->push_back((offset >> 24) & 0xff);
+    }
+  }
+}
+
+TEST(Snappy, SimpleTests) {
+  Verify("");
+  Verify("a");
+  Verify("ab");
+  Verify("abc");
+
+  Verify("aaaaaaa" + std::string(16, 'b') + std::string("aaaaa") + "abc");
+  Verify("aaaaaaa" + std::string(256, 'b') + std::string("aaaaa") + "abc");
+  Verify("aaaaaaa" + std::string(2047, 'b') + std::string("aaaaa") + "abc");
+  Verify("aaaaaaa" + std::string(65536, 'b') + std::string("aaaaa") + "abc");
+  Verify("abcaaaaaaa" + std::string(65536, 'b') + std::string("aaaaa") + "abc");
+}
+
+// Regression test for cr/345340892.
+TEST(Snappy, AppendSelfPatternExtensionEdgeCases) {
+  Verify("abcabcabcabcabcabcab");
+  Verify("abcabcabcabcabcabcab0123456789ABCDEF");
+
+  Verify("abcabcabcabcabcabcabcabcabcabcabcabc");
+  Verify("abcabcabcabcabcabcabcabcabcabcabcabc0123456789ABCDEF");
+}
+
+// Regression test for cr/345340892.
+TEST(Snappy, AppendSelfPatternExtensionEdgeCasesExhaustive) {
+  std::mt19937 rng;
+  std::uniform_int_distribution<int> uniform_byte(0, 255);
+  for (int pattern_size = 1; pattern_size <= 18; ++pattern_size) {
+    for (int length = 1; length <= 64; ++length) {
+      for (int extra_bytes_after_pattern : {0, 1, 15, 16, 128}) {
+        const int size = pattern_size + length + extra_bytes_after_pattern;
+        std::string input;
+        input.resize(size);
+        for (int i = 0; i < pattern_size; ++i) {
+          input[i] = 'a' + i;
+        }
+        for (int i = 0; i < length; ++i) {
+          input[pattern_size + i] = input[i];
+        }
+        for (int i = 0; i < extra_bytes_after_pattern; ++i) {
+          input[pattern_size + length + i] =
+              static_cast<char>(uniform_byte(rng));
+        }
+        Verify(input);
+      }
+    }
+  }
+}
+
+// Verify max blowup (lots of four-byte copies)
+TEST(Snappy, MaxBlowup) {
+  std::mt19937 rng;
+  std::uniform_int_distribution<int> uniform_byte(0, 255);
+  std::string input;
+  for (int i = 0; i < 80000; ++i)
+    input.push_back(static_cast<char>(uniform_byte(rng)));
+
+  for (int i = 0; i < 80000; i += 4) {
+    std::string four_bytes(input.end() - i - 4, input.end() - i);
+    input.append(four_bytes);
+  }
+  Verify(input);
+}
+
+TEST(Snappy, RandomData) {
+  std::minstd_rand0 rng(snappy::GetFlag(FLAGS_test_random_seed));
+  std::uniform_int_distribution<int> uniform_0_to_3(0, 3);
+  std::uniform_int_distribution<int> uniform_0_to_8(0, 8);
+  std::uniform_int_distribution<int> uniform_byte(0, 255);
+  std::uniform_int_distribution<size_t> uniform_4k(0, 4095);
+  std::uniform_int_distribution<size_t> uniform_64k(0, 65535);
+  std::bernoulli_distribution one_in_ten(1.0 / 10);
+
+  constexpr int num_ops = 20000;
+  for (int i = 0; i < num_ops; ++i) {
+    if ((i % 1000) == 0) {
+      VLOG(0) << "Random op " << i << " of " << num_ops;
+    }
+
+    std::string x;
+    size_t len = uniform_4k(rng);
+    if (i < 100) {
+      len = 65536 + uniform_64k(rng);
+    }
+    while (x.size() < len) {
+      int run_len = 1;
+      if (one_in_ten(rng)) {
+        int skewed_bits = uniform_0_to_8(rng);
+        // int is guaranteed to hold at least 16 bits, this uses at most 8 bits.
+        std::uniform_int_distribution<int> skewed_low(0,
+                                                      (1 << skewed_bits) - 1);
+        run_len = skewed_low(rng);
+      }
+      char c = static_cast<char>(uniform_byte(rng));
+      if (i >= 100) {
+        int skewed_bits = uniform_0_to_3(rng);
+        // int is guaranteed to hold at least 16 bits, this uses at most 3 bits.
+        std::uniform_int_distribution<int> skewed_low(0,
+                                                      (1 << skewed_bits) - 1);
+        c = static_cast<char>(skewed_low(rng));
+      }
+      while (run_len-- > 0 && x.size() < len) {
+        x.push_back(c);
+      }
+    }
+
+    Verify(x);
+  }
+}
+
+TEST(Snappy, FourByteOffset) {
+  // The new compressor cannot generate four-byte offsets since
+  // it chops up the input into 32KB pieces.  So we hand-emit the
+  // copy manually.
+
+  // The two fragments that make up the input string.
+  std::string fragment1 = "012345689abcdefghijklmnopqrstuvwxyz";
+  std::string fragment2 = "some other string";
+
+  // How many times each fragment is emitted.
+  const int n1 = 2;
+  const int n2 = 100000 / fragment2.size();
+  const size_t length = n1 * fragment1.size() + n2 * fragment2.size();
+
+  std::string compressed;
+  Varint::Append32(&compressed, length);
+
+  AppendLiteral(&compressed, fragment1);
+  std::string src = fragment1;
+  for (int i = 0; i < n2; ++i) {
+    AppendLiteral(&compressed, fragment2);
+    src += fragment2;
+  }
+  AppendCopy(&compressed, src.size(), fragment1.size());
+  src += fragment1;
+  CHECK_EQ(length, src.size());
+
+  std::string uncompressed;
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(snappy::Uncompress(compressed.data(), compressed.size(),
+                           &uncompressed));
+  CHECK_EQ(uncompressed, src);
+}
+
+TEST(Snappy, IOVecEdgeCases) {
+  // Test some tricky edge cases in the iovec output that are not necessarily
+  // exercised by random tests.
+
+  // Our output blocks look like this initially (the last iovec is bigger
+  // than depicted):
+  // [  ] [ ] [    ] [        ] [        ]
+  static const int kLengths[] = { 2, 1, 4, 8, 128 };
+
+  struct iovec iov[ARRAYSIZE(kLengths)];
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    iov[i].iov_base = new char[kLengths[i]];
+    iov[i].iov_len = kLengths[i];
+  }
+
+  std::string compressed;
+  Varint::Append32(&compressed, 22);
+
+  // A literal whose output crosses three blocks.
+  // [ab] [c] [123 ] [        ] [        ]
+  AppendLiteral(&compressed, "abc123");
+
+  // A copy whose output crosses two blocks (source and destination
+  // segments marked).
+  // [ab] [c] [1231] [23      ] [        ]
+  //           ^--^   --
+  AppendCopy(&compressed, 3, 3);
+
+  // A copy where the input is, at first, in the block before the output:
+  //
+  // [ab] [c] [1231] [231231  ] [        ]
+  //           ^---     ^---
+  // Then during the copy, the pointers move such that the input and
+  // output pointers are in the same block:
+  //
+  // [ab] [c] [1231] [23123123] [        ]
+  //                  ^-    ^-
+  // And then they move again, so that the output pointer is no longer
+  // in the same block as the input pointer:
+  // [ab] [c] [1231] [23123123] [123     ]
+  //                    ^--      ^--
+  AppendCopy(&compressed, 6, 9);
+
+  // Finally, a copy where the input is from several blocks back,
+  // and it also crosses three blocks:
+  //
+  // [ab] [c] [1231] [23123123] [123b    ]
+  //   ^                            ^
+  // [ab] [c] [1231] [23123123] [123bc   ]
+  //       ^                         ^
+  // [ab] [c] [1231] [23123123] [123bc12 ]
+  //           ^-                     ^-
+  AppendCopy(&compressed, 17, 4);
+
+  CHECK(snappy::RawUncompressToIOVec(
+      compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+  CHECK_EQ(0, memcmp(iov[0].iov_base, "ab", 2));
+  CHECK_EQ(0, memcmp(iov[1].iov_base, "c", 1));
+  CHECK_EQ(0, memcmp(iov[2].iov_base, "1231", 4));
+  CHECK_EQ(0, memcmp(iov[3].iov_base, "23123123", 8));
+  CHECK_EQ(0, memcmp(iov[4].iov_base, "123bc12", 7));
+
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    delete[] reinterpret_cast<char *>(iov[i].iov_base);
+  }
+}
+
+TEST(Snappy, IOVecLiteralOverflow) {
+  static const int kLengths[] = { 3, 4 };
+
+  struct iovec iov[ARRAYSIZE(kLengths)];
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    iov[i].iov_base = new char[kLengths[i]];
+    iov[i].iov_len = kLengths[i];
+  }
+
+  std::string compressed;
+  Varint::Append32(&compressed, 8);
+
+  AppendLiteral(&compressed, "12345678");
+
+  CHECK(!snappy::RawUncompressToIOVec(
+      compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    delete[] reinterpret_cast<char *>(iov[i].iov_base);
+  }
+}
+
+TEST(Snappy, IOVecCopyOverflow) {
+  static const int kLengths[] = { 3, 4 };
+
+  struct iovec iov[ARRAYSIZE(kLengths)];
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    iov[i].iov_base = new char[kLengths[i]];
+    iov[i].iov_len = kLengths[i];
+  }
+
+  std::string compressed;
+  Varint::Append32(&compressed, 8);
+
+  AppendLiteral(&compressed, "123");
+  AppendCopy(&compressed, 3, 5);
+
+  CHECK(!snappy::RawUncompressToIOVec(
+      compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+
+  for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+    delete[] reinterpret_cast<char *>(iov[i].iov_base);
+  }
+}
+
+bool CheckUncompressedLength(const std::string& compressed, size_t* ulength) {
+  const bool result1 = snappy::GetUncompressedLength(compressed.data(),
+                                                     compressed.size(),
+                                                     ulength);
+
+  snappy::ByteArraySource source(compressed.data(), compressed.size());
+  uint32_t length;
+  const bool result2 = snappy::GetUncompressedLength(&source, &length);
+  CHECK_EQ(result1, result2);
+  return result1;
+}
+
+TEST(SnappyCorruption, TruncatedVarint) {
+  std::string compressed, uncompressed;
+  size_t ulength;
+  compressed.push_back('\xf0');
+  CHECK(!CheckUncompressedLength(compressed, &ulength));
+  CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+                            &uncompressed));
+}
+
+TEST(SnappyCorruption, UnterminatedVarint) {
+  std::string compressed, uncompressed;
+  size_t ulength;
+  compressed.push_back('\x80');
+  compressed.push_back('\x80');
+  compressed.push_back('\x80');
+  compressed.push_back('\x80');
+  compressed.push_back('\x80');
+  compressed.push_back(10);
+  CHECK(!CheckUncompressedLength(compressed, &ulength));
+  CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+                            &uncompressed));
+}
+
+TEST(SnappyCorruption, OverflowingVarint) {
+  std::string compressed, uncompressed;
+  size_t ulength;
+  compressed.push_back('\xfb');
+  compressed.push_back('\xff');
+  compressed.push_back('\xff');
+  compressed.push_back('\xff');
+  compressed.push_back('\x7f');
+  CHECK(!CheckUncompressedLength(compressed, &ulength));
+  CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+                            &uncompressed));
+}
+
+TEST(Snappy, ReadPastEndOfBuffer) {
+  // Check that we do not read past end of input
+
+  // Make a compressed string that ends with a single-byte literal
+  std::string compressed;
+  Varint::Append32(&compressed, 1);
+  AppendLiteral(&compressed, "x");
+
+  std::string uncompressed;
+  DataEndingAtUnreadablePage c(compressed);
+  CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+  CHECK_EQ(uncompressed, std::string("x"));
+}
+
+// Check for an infinite loop caused by a copy with offset==0
+TEST(Snappy, ZeroOffsetCopy) {
+  const char* compressed = "\x40\x12\x00\x00";
+  //  \x40              Length (must be > kMaxIncrementCopyOverflow)
+  //  \x12\x00\x00      Copy with offset==0, length==5
+  char uncompressed[100];
+  EXPECT_FALSE(snappy::RawUncompress(compressed, 4, uncompressed));
+}
+
+TEST(Snappy, ZeroOffsetCopyValidation) {
+  const char* compressed = "\x05\x12\x00\x00";
+  //  \x05              Length
+  //  \x12\x00\x00      Copy with offset==0, length==5
+  EXPECT_FALSE(snappy::IsValidCompressedBuffer(compressed, 4));
+}
+
+int TestFindMatchLength(const char* s1, const char *s2, unsigned length) {
+  uint64_t data;
+  std::pair<size_t, bool> p =
+      snappy::internal::FindMatchLength(s1, s2, s2 + length, &data);
+  CHECK_EQ(p.first < 8, p.second);
+  return p.first;
+}
+
+TEST(Snappy, FindMatchLength) {
+  // Exercise all different code paths through the function.
+  // 64-bit version:
+
+  // Hit s1_limit in 64-bit loop, hit s1_limit in single-character loop.
+  EXPECT_EQ(6, TestFindMatchLength("012345", "012345", 6));
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc", "01234567abc", 11));
+
+  // Hit s1_limit in 64-bit loop, find a non-match in single-character loop.
+  EXPECT_EQ(9, TestFindMatchLength("01234567abc", "01234567axc", 9));
+
+  // Same, but edge cases.
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc!", 11));
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc?", 11));
+
+  // Find non-match at once in first loop.
+  EXPECT_EQ(0, TestFindMatchLength("01234567xxxxxxxx", "?1234567xxxxxxxx", 16));
+  EXPECT_EQ(1, TestFindMatchLength("01234567xxxxxxxx", "0?234567xxxxxxxx", 16));
+  EXPECT_EQ(4, TestFindMatchLength("01234567xxxxxxxx", "01237654xxxxxxxx", 16));
+  EXPECT_EQ(7, TestFindMatchLength("01234567xxxxxxxx", "0123456?xxxxxxxx", 16));
+
+  // Find non-match in first loop after one block.
+  EXPECT_EQ(8, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                   "abcdefgh?1234567xxxxxxxx", 24));
+  EXPECT_EQ(9, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                   "abcdefgh0?234567xxxxxxxx", 24));
+  EXPECT_EQ(12, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                    "abcdefgh01237654xxxxxxxx", 24));
+  EXPECT_EQ(15, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                    "abcdefgh0123456?xxxxxxxx", 24));
+
+  // 32-bit version:
+
+  // Short matches.
+  EXPECT_EQ(0, TestFindMatchLength("01234567", "?1234567", 8));
+  EXPECT_EQ(1, TestFindMatchLength("01234567", "0?234567", 8));
+  EXPECT_EQ(2, TestFindMatchLength("01234567", "01?34567", 8));
+  EXPECT_EQ(3, TestFindMatchLength("01234567", "012?4567", 8));
+  EXPECT_EQ(4, TestFindMatchLength("01234567", "0123?567", 8));
+  EXPECT_EQ(5, TestFindMatchLength("01234567", "01234?67", 8));
+  EXPECT_EQ(6, TestFindMatchLength("01234567", "012345?7", 8));
+  EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 8));
+  EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 7));
+  EXPECT_EQ(7, TestFindMatchLength("01234567!", "0123456??", 7));
+
+  // Hit s1_limit in 32-bit loop, hit s1_limit in single-character loop.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd", "xxxxxxabcd", 10));
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd?", "xxxxxxabcd?", 10));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcdef", "xxxxxxabcdef", 13));
+
+  // Same, but edge cases.
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc!", 12));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc?", 12));
+
+  // Hit s1_limit in 32-bit loop, find a non-match in single-character loop.
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxx0123abc", "xxxxxx0123axc", 13));
+
+  // Find non-match at once in first loop.
+  EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx?123xxxxxxxx", 18));
+  EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx0?23xxxxxxxx", 18));
+  EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx0132xxxxxxxx", 18));
+  EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx012?xxxxxxxx", 18));
+
+  // Same, but edge cases.
+  EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123", "xxxxxx?123", 10));
+  EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123", "xxxxxx0?23", 10));
+  EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123", "xxxxxx0132", 10));
+  EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123", "xxxxxx012?", 10));
+
+  // Find non-match in first loop after one block.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd?123xx", 16));
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd0?23xx", 16));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd0132xx", 16));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd012?xx", 16));
+
+  // Same, but edge cases.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd?123", 14));
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0?23", 14));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0132", 14));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd012?", 14));
+}
+
+TEST(Snappy, FindMatchLengthRandom) {
+  constexpr int kNumTrials = 10000;
+  constexpr int kTypicalLength = 10;
+  std::minstd_rand0 rng(snappy::GetFlag(FLAGS_test_random_seed));
+  std::uniform_int_distribution<int> uniform_byte(0, 255);
+  std::bernoulli_distribution one_in_two(1.0 / 2);
+  std::bernoulli_distribution one_in_typical_length(1.0 / kTypicalLength);
+
+  for (int i = 0; i < kNumTrials; ++i) {
+    std::string s, t;
+    char a = static_cast<char>(uniform_byte(rng));
+    char b = static_cast<char>(uniform_byte(rng));
+    while (!one_in_typical_length(rng)) {
+      s.push_back(one_in_two(rng) ? a : b);
+      t.push_back(one_in_two(rng) ? a : b);
+    }
+    DataEndingAtUnreadablePage u(s);
+    DataEndingAtUnreadablePage v(t);
+    size_t matched = TestFindMatchLength(u.data(), v.data(), t.size());
+    if (matched == t.size()) {
+      EXPECT_EQ(s, t);
+    } else {
+      EXPECT_NE(s[matched], t[matched]);
+      for (size_t j = 0; j < matched; ++j) {
+        EXPECT_EQ(s[j], t[j]);
+      }
+    }
+  }
+}
+
+uint16_t MakeEntry(unsigned int extra, unsigned int len,
+                   unsigned int copy_offset) {
+  // Check that all of the fields fit within the allocated space
+  assert(extra       == (extra & 0x7));          // At most 3 bits
+  assert(copy_offset == (copy_offset & 0x7));    // At most 3 bits
+  assert(len         == (len & 0x7f));           // At most 7 bits
+  return len | (copy_offset << 8) | (extra << 11);
+}
+
+// Check that the decompression table is correct, and optionally print out
+// the computed one.
+TEST(Snappy, VerifyCharTable) {
+  using snappy::internal::LITERAL;
+  using snappy::internal::COPY_1_BYTE_OFFSET;
+  using snappy::internal::COPY_2_BYTE_OFFSET;
+  using snappy::internal::COPY_4_BYTE_OFFSET;
+  using snappy::internal::char_table;
+
+  uint16_t 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 (uint8_t 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 (uint8_t 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 (uint8_t len = 4; len < 12; ++len) {
+    for (uint16_t offset = 0; offset < 2048; offset += 256) {
+      uint8_t offset_high = static_cast<uint8_t>(offset >> 8);
+      dst[COPY_1_BYTE_OFFSET | ((len - 4) << 2) | (offset_high << 5)] =
+          MakeEntry(1, len, offset_high);
+      assigned++;
+    }
+  }
+
+  // COPY_2_BYTE_OFFSET.
+  // Tag contains len-1 in top 6 bits, and offset in next two bytes.
+  for (uint8_t 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 (uint8_t 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.
+  EXPECT_EQ(256, assigned) << "Assigned only " << assigned << " of 256";
+  for (int i = 0; i < 256; ++i) {
+    EXPECT_NE(0xffff, dst[i]) << "Did not assign byte " << i;
+  }
+
+  if (snappy::GetFlag(FLAGS_snappy_dump_decompression_table)) {
+    std::printf("static const uint16_t char_table[256] = {\n  ");
+    for (int i = 0; i < 256; ++i) {
+      std::printf("0x%04x%s",
+                  dst[i],
+                  ((i == 255) ? "\n" : (((i % 8) == 7) ? ",\n  " : ", ")));
+    }
+    std::printf("};\n");
+  }
+
+  // Check that computed table matched recorded table.
+  for (int i = 0; i < 256; ++i) {
+    EXPECT_EQ(dst[i], char_table[i]) << "Mismatch in byte " << i;
+  }
+}
+
+TEST(Snappy, TestBenchmarkFiles) {
+  for (int i = 0; i < ARRAYSIZE(kTestDataFiles); ++i) {
+    Verify(ReadTestDataFile(kTestDataFiles[i].filename,
+                            kTestDataFiles[i].size_limit));
+  }
+}
+
+}  // namespace
+
+}  // namespace snappy