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snappy/snappy_unittest.cc

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// 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 <math.h>
#include <stdlib.h>
#include <algorithm>
#include <string>
#include <vector>
#include "snappy.h"
#include "snappy-internal.h"
#include "snappy-test.h"
#include "snappy-sinksource.h"
DEFINE_int32(start_len, -1,
"Starting prefix size for testing (-1: just full file contents)");
DEFINE_int32(end_len, -1,
"Starting prefix size for testing (-1: just full file contents)");
DEFINE_int32(bytes, 10485760,
"How many bytes to compress/uncompress per file for timing");
DEFINE_bool(zlib, false,
"Run zlib compression (http://www.zlib.net)");
DEFINE_bool(lzo, false,
"Run LZO compression (http://www.oberhumer.com/opensource/lzo/)");
DEFINE_bool(quicklz, false,
"Run quickLZ compression (http://www.quicklz.com/)");
DEFINE_bool(liblzf, false,
"Run libLZF compression "
"(http://www.goof.com/pcg/marc/liblzf.html)");
DEFINE_bool(fastlz, false,
"Run FastLZ compression (http://www.fastlz.org/");
DEFINE_bool(snappy, true, "Run snappy compression");
DEFINE_bool(write_compressed, false,
"Write compressed versions of each file to <file>.comp");
DEFINE_bool(write_uncompressed, false,
"Write uncompressed versions of each file to <file>.uncomp");
namespace snappy {
#ifdef HAVE_FUNC_MMAP
// 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 string& s) {
const size_t page_size = getpagesize();
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;
memcpy(dst, s.data(), size);
data_ = dst;
size_ = size;
// Make guard page unreadable.
CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_NONE));
}
~DataEndingAtUnreadablePage() {
// Undo the mprotect.
CHECK_EQ(0, mprotect(protected_page_, getpagesize(), 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 // HAVE_FUNC_MMAP
// Fallback for systems without mmap.
typedef string DataEndingAtUnreadablePage;
#endif
enum CompressorType {
ZLIB, LZO, LIBLZF, QUICKLZ, FASTLZ, SNAPPY
};
const char* names[] = {
"ZLIB", "LZO", "LIBLZF", "QUICKLZ", "FASTLZ", "SNAPPY"
};
static size_t MinimumRequiredOutputSpace(size_t input_size,
CompressorType comp) {
switch (comp) {
#ifdef ZLIB_VERSION
case ZLIB:
return ZLib::MinCompressbufSize(input_size);
#endif // ZLIB_VERSION
#ifdef LZO_VERSION
case LZO:
return input_size + input_size/64 + 16 + 3;
#endif // LZO_VERSION
#ifdef LZF_VERSION
case LIBLZF:
return input_size;
#endif // LZF_VERSION
#ifdef QLZ_VERSION_MAJOR
case QUICKLZ:
return input_size + 36000; // 36000 is used for scratch.
#endif // QLZ_VERSION_MAJOR
#ifdef FASTLZ_VERSION
case FASTLZ:
return max(static_cast<int>(ceil(input_size * 1.05)), 66);
#endif // FASTLZ_VERSION
case SNAPPY:
return snappy::MaxCompressedLength(input_size);
default:
LOG(FATAL) << "Unknown compression type number " << comp;
}
}
// Returns true if we successfully compressed, false otherwise.
//
// If compressed_is_preallocated is set, do not resize the compressed buffer.
// This is typically what you want for a benchmark, in order to not spend
// time in the memory allocator. If you do set this flag, however,
// "compressed" must be preinitialized to at least MinCompressbufSize(comp)
// number of bytes, and may contain junk bytes at the end after return.
static bool Compress(const char* input, size_t input_size, CompressorType comp,
string* compressed, bool compressed_is_preallocated) {
if (!compressed_is_preallocated) {
compressed->resize(MinimumRequiredOutputSpace(input_size, comp));
}
switch (comp) {
#ifdef ZLIB_VERSION
case ZLIB: {
ZLib zlib;
uLongf destlen = compressed->size();
int ret = zlib.Compress(
reinterpret_cast<Bytef*>(string_as_array(compressed)),
&destlen,
reinterpret_cast<const Bytef*>(input),
input_size);
CHECK_EQ(Z_OK, ret);
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
return true;
}
#endif // ZLIB_VERSION
#ifdef LZO_VERSION
case LZO: {
unsigned char* mem = new unsigned char[LZO1X_1_15_MEM_COMPRESS];
lzo_uint destlen;
int ret = lzo1x_1_15_compress(
reinterpret_cast<const uint8*>(input),
input_size,
reinterpret_cast<uint8*>(string_as_array(compressed)),
&destlen,
mem);
CHECK_EQ(LZO_E_OK, ret);
delete[] mem;
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
break;
}
#endif // LZO_VERSION
#ifdef LZF_VERSION
case LIBLZF: {
int destlen = lzf_compress(input,
input_size,
string_as_array(compressed),
input_size);
if (destlen == 0) {
// lzf *can* cause lots of blowup when compressing, so they
// recommend to limit outsize to insize, and just not compress
// if it's bigger. Ideally, we'd just swap input and output.
compressed->assign(input, input_size);
destlen = input_size;
}
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
break;
}
#endif // LZF_VERSION
#ifdef QLZ_VERSION_MAJOR
case QUICKLZ: {
qlz_state_compress *state_compress = new qlz_state_compress;
int destlen = qlz_compress(input,
string_as_array(compressed),
input_size,
state_compress);
delete state_compress;
CHECK_NE(0, destlen);
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
break;
}
#endif // QLZ_VERSION_MAJOR
#ifdef FASTLZ_VERSION
case FASTLZ: {
// Use level 1 compression since we mostly care about speed.
int destlen = fastlz_compress_level(
1,
input,
input_size,
string_as_array(compressed));
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
CHECK_NE(destlen, 0);
break;
}
#endif // FASTLZ_VERSION
case SNAPPY: {
size_t destlen;
snappy::RawCompress(input, input_size,
string_as_array(compressed),
&destlen);
CHECK_LE(destlen, snappy::MaxCompressedLength(input_size));
if (!compressed_is_preallocated) {
compressed->resize(destlen);
}
break;
}
default: {
return false; // the asked-for library wasn't compiled in
}
}
return true;
}
static bool Uncompress(const string& compressed, CompressorType comp,
int size, string* output) {
switch (comp) {
#ifdef ZLIB_VERSION
case ZLIB: {
output->resize(size);
ZLib zlib;
uLongf destlen = output->size();
int ret = zlib.Uncompress(
reinterpret_cast<Bytef*>(string_as_array(output)),
&destlen,
reinterpret_cast<const Bytef*>(compressed.data()),
compressed.size());
CHECK_EQ(Z_OK, ret);
CHECK_EQ(static_cast<uLongf>(size), destlen);
break;
}
#endif // ZLIB_VERSION
#ifdef LZO_VERSION
case LZO: {
output->resize(size);
lzo_uint destlen;
int ret = lzo1x_decompress(
reinterpret_cast<const uint8*>(compressed.data()),
compressed.size(),
reinterpret_cast<uint8*>(string_as_array(output)),
&destlen,
NULL);
CHECK_EQ(LZO_E_OK, ret);
CHECK_EQ(static_cast<lzo_uint>(size), destlen);
break;
}
#endif // LZO_VERSION
#ifdef LZF_VERSION
case LIBLZF: {
output->resize(size);
int destlen = lzf_decompress(compressed.data(),
compressed.size(),
string_as_array(output),
output->size());
if (destlen == 0) {
// This error probably means we had decided not to compress,
// and thus have stored input in output directly.
output->assign(compressed.data(), compressed.size());
destlen = compressed.size();
}
CHECK_EQ(destlen, size);
break;
}
#endif // LZF_VERSION
#ifdef QLZ_VERSION_MAJOR
case QUICKLZ: {
output->resize(size);
qlz_state_decompress *state_decompress = new qlz_state_decompress;
int destlen = qlz_decompress(compressed.data(),
string_as_array(output),
state_decompress);
delete state_decompress;
CHECK_EQ(destlen, size);
break;
}
#endif // QLZ_VERSION_MAJOR
#ifdef FASTLZ_VERSION
case FASTLZ: {
output->resize(size);
int destlen = fastlz_decompress(compressed.data(),
compressed.length(),
string_as_array(output),
size);
CHECK_EQ(destlen, size);
break;
}
#endif // FASTLZ_VERSION
case SNAPPY: {
snappy::RawUncompress(compressed.data(), compressed.size(),
string_as_array(output));
break;
}
default: {
return false; // the asked-for library wasn't compiled in
}
}
return true;
}
static void Measure(const char* data,
size_t length,
CompressorType comp,
int repeats,
int block_size) {
// Run tests a few time and pick median running times
static const int kRuns = 5;
double ctime[kRuns];
double utime[kRuns];
int compressed_size = 0;
{
// Chop the input into blocks
int num_blocks = (length + block_size - 1) / block_size;
vector<const char*> input(num_blocks);
vector<size_t> input_length(num_blocks);
vector<string> compressed(num_blocks);
vector<string> output(num_blocks);
for (int b = 0; b < num_blocks; b++) {
int input_start = b * block_size;
int input_limit = min<int>((b+1)*block_size, length);
input[b] = data+input_start;
input_length[b] = input_limit-input_start;
// Pre-grow the output buffer so we don't measure string append time.
compressed[b].resize(MinimumRequiredOutputSpace(block_size, comp));
}
// First, try one trial compression to make sure the code is compiled in
if (!Compress(input[0], input_length[0], comp, &compressed[0], true)) {
LOG(WARNING) << "Skipping " << names[comp] << ": "
<< "library not compiled in";
return;
}
for (int run = 0; run < kRuns; run++) {
CycleTimer ctimer, utimer;
for (int b = 0; b < num_blocks; b++) {
// Pre-grow the output buffer so we don't measure string append time.
compressed[b].resize(MinimumRequiredOutputSpace(block_size, comp));
}
ctimer.Start();
for (int b = 0; b < num_blocks; b++)
for (int i = 0; i < repeats; i++)
Compress(input[b], input_length[b], comp, &compressed[b], true);
ctimer.Stop();
// Compress once more, with resizing, so we don't leave junk
// at the end that will confuse the decompressor.
for (int b = 0; b < num_blocks; b++) {
Compress(input[b], input_length[b], comp, &compressed[b], false);
}
for (int b = 0; b < num_blocks; b++) {
output[b].resize(input_length[b]);
}
utimer.Start();
for (int i = 0; i < repeats; i++)
for (int b = 0; b < num_blocks; b++)
Uncompress(compressed[b], comp, input_length[b], &output[b]);
utimer.Stop();
ctime[run] = ctimer.Get();
utime[run] = utimer.Get();
}
compressed_size = 0;
for (int i = 0; i < compressed.size(); i++) {
compressed_size += compressed[i].size();
}
}
sort(ctime, ctime + kRuns);
sort(utime, utime + kRuns);
const int med = kRuns/2;
float comp_rate = (length / ctime[med]) * repeats / 1048576.0;
float uncomp_rate = (length / utime[med]) * repeats / 1048576.0;
string x = names[comp];
x += ":";
string urate = (uncomp_rate >= 0)
? StringPrintf("%.1f", uncomp_rate)
: string("?");
printf("%-7s [b %dM] bytes %6d -> %6d %4.1f%% "
"comp %5.1f MB/s uncomp %5s MB/s\n",
x.c_str(),
block_size/(1<<20),
static_cast<int>(length), static_cast<uint32>(compressed_size),
(compressed_size * 100.0) / max<int>(1, length),
comp_rate,
urate.c_str());
}
static int VerifyString(const string& input) {
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()));
string uncompressed;
DataEndingAtUnreadablePage c(compressed);
CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
CHECK_EQ(uncompressed, input);
return uncompressed.size();
}
static void VerifyIOVec(const string& input) {
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()];
ACMRandom rnd(input.size());
int num = rnd.Next() % 10 + 1;
if (input.size() < num) {
num = input.size();
}
struct iovec* iov = new iovec[num];
int used_so_far = 0;
for (int i = 0; i < num; ++i) {
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 (rnd.OneIn(5)) {
iov[i].iov_len = 0;
} else {
iov[i].iov_len = rnd.Uniform(input.size());
}
}
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.
static void VerifyNonBlockedCompression(const string& input) {
if (input.length() > snappy::kBlockSize) {
// We cannot test larger blocks than the maximum block size, obviously.
return;
}
string prefix;
Varint::Append32(&prefix, input.size());
// Setup compression table
snappy::internal::WorkingMemory wmem;
int table_size;
uint16* table = wmem.GetHashTable(input.size(), &table_size);
// Compress entire input in one shot
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 string
string uncomp_str;
CHECK(snappy::Uncompress(compressed.data(), compressed.size(), &uncomp_str));
CHECK_EQ(uncomp_str, input);
}
// Expand the input so that it is at least K times as big as block size
static string Expand(const string& input) {
static const int K = 3;
string data = input;
while (data.size() < K * snappy::kBlockSize) {
data += input;
}
return data;
}
static int Verify(const string& input) {
VLOG(1) << "Verifying input of size " << input.size();
// Compress using string based routines
const int result = VerifyString(input);
VerifyNonBlockedCompression(input);
VerifyIOVec(input);
if (!input.empty()) {
const string expanded = Expand(input);
VerifyNonBlockedCompression(expanded);
VerifyIOVec(input);
}
return result;
}
// This test checks to ensure that snappy doesn't coredump if it gets
// corrupted data.
static bool IsValidCompressedBuffer(const string& c) {
return snappy::IsValidCompressedBuffer(c.data(), c.size());
}
static bool Uncompress(const string& c, string* u) {
return snappy::Uncompress(c.data(), c.size(), u);
}
TYPED_TEST(CorruptedTest, VerifyCorrupted) {
string source = "making sure we don't crash with corrupted input";
VLOG(1) << source;
string dest;
TypeParam 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(TypeParam(dest)));
CHECK(!Uncompress(TypeParam(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 (int i = 0; i < source.length(); ++i) {
source[i] = 'A';
}
snappy::Compress(source.data(), source.size(), &dest);
dest[0] = dest[1] = dest[2] = dest[3] = 0;
CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
CHECK(!Uncompress(TypeParam(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] = 0xff;
// This decodes to a really large size, i.e., about 3 GB.
dest[4] = 'k';
CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
CHECK(!Uncompress(TypeParam(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] = 0xff;
dest[3] = 0x00;
CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
CHECK(!Uncompress(TypeParam(dest), &uncmp));
// try reading stuff in from a bad file.
for (int i = 1; i <= 3; ++i) {
string data = ReadTestDataFile(StringPrintf("baddata%d.snappy", i).c_str(),
0);
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 ulen2;
snappy::ByteArraySource source(data.data(), data.size());
CHECK(!snappy::GetUncompressedLength(&source, &ulen2) ||
(ulen2 < (1<<20)));
CHECK(!IsValidCompressedBuffer(TypeParam(data)));
CHECK(!Uncompress(TypeParam(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.
static void AppendLiteral(string* dst, const 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 += string(number, count);
}
*dst += literal;
}
static void AppendCopy(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" + string(16, 'b') + string("aaaaa") + "abc");
Verify("aaaaaaa" + string(256, 'b') + string("aaaaa") + "abc");
Verify("aaaaaaa" + string(2047, 'b') + string("aaaaa") + "abc");
Verify("aaaaaaa" + string(65536, 'b') + string("aaaaa") + "abc");
Verify("abcaaaaaaa" + string(65536, 'b') + string("aaaaa") + "abc");
}
// Verify max blowup (lots of four-byte copies)
TEST(Snappy, MaxBlowup) {
string input;
for (int i = 0; i < 20000; i++) {
ACMRandom rnd(i);
uint32 bytes = static_cast<uint32>(rnd.Next());
input.append(reinterpret_cast<char*>(&bytes), sizeof(bytes));
}
for (int i = 19999; i >= 0; i--) {
ACMRandom rnd(i);
uint32 bytes = static_cast<uint32>(rnd.Next());
input.append(reinterpret_cast<char*>(&bytes), sizeof(bytes));
}
Verify(input);
}
TEST(Snappy, RandomData) {
ACMRandom rnd(FLAGS_test_random_seed);
const int num_ops = 20000;
for (int i = 0; i < num_ops; i++) {
if ((i % 1000) == 0) {
VLOG(0) << "Random op " << i << " of " << num_ops;
}
string x;
int len = rnd.Uniform(4096);
if (i < 100) {
len = 65536 + rnd.Uniform(65536);
}
while (x.size() < len) {
int run_len = 1;
if (rnd.OneIn(10)) {
run_len = rnd.Skewed(8);
}
char c = (i < 100) ? rnd.Uniform(256) : rnd.Skewed(3);
while (run_len-- > 0 && x.size() < len) {
x += 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.
string fragment1 = "012345689abcdefghijklmnopqrstuvwxyz";
string fragment2 = "some other string";
// How many times each fragment is emitted.
const int n1 = 2;
const int n2 = 100000 / fragment2.size();
const int length = n1 * fragment1.size() + n2 * fragment2.size();
string compressed;
Varint::Append32(&compressed, length);
AppendLiteral(&compressed, fragment1);
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());
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];
}
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];
}
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];
}
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);
}
}
static bool CheckUncompressedLength(const string& compressed,
size_t* ulength) {
const bool result1 = snappy::GetUncompressedLength(compressed.data(),
compressed.size(),
ulength);
snappy::ByteArraySource source(compressed.data(), compressed.size());
uint32 length;
const bool result2 = snappy::GetUncompressedLength(&source, &length);
CHECK_EQ(result1, result2);
return result1;
}
TEST(SnappyCorruption, TruncatedVarint) {
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) {
string compressed, uncompressed;
size_t ulength;
compressed.push_back(128);
compressed.push_back(128);
compressed.push_back(128);
compressed.push_back(128);
compressed.push_back(128);
compressed.push_back(10);
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
string compressed;
Varint::Append32(&compressed, 1);
AppendLiteral(&compressed, "x");
string uncompressed;
DataEndingAtUnreadablePage c(compressed);
CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
CHECK_EQ(uncompressed, 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));
}
namespace {
int TestFindMatchLength(const char* s1, const char *s2, unsigned length) {
return snappy::internal::FindMatchLength(s1, s2, s2 + length);
}
} // namespace
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) {
const int kNumTrials = 10000;
const int kTypicalLength = 10;
ACMRandom rnd(FLAGS_test_random_seed);
for (int i = 0; i < kNumTrials; i++) {
string s, t;
char a = rnd.Rand8();
char b = rnd.Rand8();
while (!rnd.OneIn(kTypicalLength)) {
s.push_back(rnd.OneIn(2) ? a : b);
t.push_back(rnd.OneIn(2) ? a : b);
}
DataEndingAtUnreadablePage u(s);
DataEndingAtUnreadablePage v(t);
int matched = snappy::internal::FindMatchLength(
u.data(), v.data(), v.data() + t.size());
if (matched == t.size()) {
EXPECT_EQ(s, t);
} else {
EXPECT_NE(s[matched], t[matched]);
for (int j = 0; j < matched; j++) {
EXPECT_EQ(s[j], t[j]);
}
}
}
}
static void CompressFile(const char* fname) {
string fullinput;
file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
string compressed;
Compress(fullinput.data(), fullinput.size(), SNAPPY, &compressed, false);
file::SetContents(string(fname).append(".comp"), compressed, file::Defaults())
.CheckSuccess();
}
static void UncompressFile(const char* fname) {
string fullinput;
file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
size_t uncompLength;
CHECK(CheckUncompressedLength(fullinput, &uncompLength));
string uncompressed;
uncompressed.resize(uncompLength);
CHECK(snappy::Uncompress(fullinput.data(), fullinput.size(), &uncompressed));
file::SetContents(string(fname).append(".uncomp"), uncompressed,
file::Defaults()).CheckSuccess();
}
static void MeasureFile(const char* fname) {
string fullinput;
file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
printf("%-40s :\n", fname);
int start_len = (FLAGS_start_len < 0) ? fullinput.size() : FLAGS_start_len;
int end_len = fullinput.size();
if (FLAGS_end_len >= 0) {
end_len = min<int>(fullinput.size(), FLAGS_end_len);
}
for (int len = start_len; len <= end_len; len++) {
const char* const input = fullinput.data();
int repeats = (FLAGS_bytes + len) / (len + 1);
if (FLAGS_zlib) Measure(input, len, ZLIB, repeats, 1024<<10);
if (FLAGS_lzo) Measure(input, len, LZO, repeats, 1024<<10);
if (FLAGS_liblzf) Measure(input, len, LIBLZF, repeats, 1024<<10);
if (FLAGS_quicklz) Measure(input, len, QUICKLZ, repeats, 1024<<10);
if (FLAGS_fastlz) Measure(input, len, FASTLZ, repeats, 1024<<10);
if (FLAGS_snappy) Measure(input, len, SNAPPY, repeats, 4096<<10);
// For block-size based measurements
if (0 && FLAGS_snappy) {
Measure(input, len, SNAPPY, repeats, 8<<10);
Measure(input, len, SNAPPY, repeats, 16<<10);
Measure(input, len, SNAPPY, repeats, 32<<10);
Measure(input, len, SNAPPY, repeats, 64<<10);
Measure(input, len, SNAPPY, repeats, 256<<10);
Measure(input, len, SNAPPY, repeats, 1024<<10);
}
}
}
static struct {
const char* label;
const char* filename;
size_t size_limit;
} files[] = {
{ "html", "html", 0 },
{ "urls", "urls.10K", 0 },
{ "jpg", "fireworks.jpeg", 0 },
{ "jpg_200", "fireworks.jpeg", 200 },
{ "pdf", "paper-100k.pdf", 0 },
{ "html4", "html_x_4", 0 },
{ "txt1", "alice29.txt", 0 },
{ "txt2", "asyoulik.txt", 0 },
{ "txt3", "lcet10.txt", 0 },
{ "txt4", "plrabn12.txt", 0 },
{ "pb", "geo.protodata", 0 },
{ "gaviota", "kppkn.gtb", 0 },
};
static void BM_UFlat(int iters, int arg) {
StopBenchmarkTiming();
// Pick file to process based on "arg"
CHECK_GE(arg, 0);
CHECK_LT(arg, ARRAYSIZE(files));
string contents = ReadTestDataFile(files[arg].filename,
files[arg].size_limit);
string zcontents;
snappy::Compress(contents.data(), contents.size(), &zcontents);
char* dst = new char[contents.size()];
SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
static_cast<int64>(contents.size()));
SetBenchmarkLabel(files[arg].label);
StartBenchmarkTiming();
while (iters-- > 0) {
CHECK(snappy::RawUncompress(zcontents.data(), zcontents.size(), dst));
}
StopBenchmarkTiming();
delete[] dst;
}
BENCHMARK(BM_UFlat)->DenseRange(0, ARRAYSIZE(files) - 1);
static void BM_UValidate(int iters, int arg) {
StopBenchmarkTiming();
// Pick file to process based on "arg"
CHECK_GE(arg, 0);
CHECK_LT(arg, ARRAYSIZE(files));
string contents = ReadTestDataFile(files[arg].filename,
files[arg].size_limit);
string zcontents;
snappy::Compress(contents.data(), contents.size(), &zcontents);
SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
static_cast<int64>(contents.size()));
SetBenchmarkLabel(files[arg].label);
StartBenchmarkTiming();
while (iters-- > 0) {
CHECK(snappy::IsValidCompressedBuffer(zcontents.data(), zcontents.size()));
}
StopBenchmarkTiming();
}
BENCHMARK(BM_UValidate)->DenseRange(0, 4);
static void BM_UIOVec(int iters, int arg) {
StopBenchmarkTiming();
// Pick file to process based on "arg"
CHECK_GE(arg, 0);
CHECK_LT(arg, ARRAYSIZE(files));
string contents = ReadTestDataFile(files[arg].filename,
files[arg].size_limit);
string zcontents;
snappy::Compress(contents.data(), contents.size(), &zcontents);
// Uncompress into an iovec containing ten entries.
const int kNumEntries = 10;
struct iovec iov[kNumEntries];
char *dst = new char[contents.size()];
int used_so_far = 0;
for (int i = 0; i < kNumEntries; ++i) {
iov[i].iov_base = dst + used_so_far;
if (used_so_far == contents.size()) {
iov[i].iov_len = 0;
continue;
}
if (i == kNumEntries - 1) {
iov[i].iov_len = contents.size() - used_so_far;
} else {
iov[i].iov_len = contents.size() / kNumEntries;
}
used_so_far += iov[i].iov_len;
}
SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
static_cast<int64>(contents.size()));
SetBenchmarkLabel(files[arg].label);
StartBenchmarkTiming();
while (iters-- > 0) {
CHECK(snappy::RawUncompressToIOVec(zcontents.data(), zcontents.size(), iov,
kNumEntries));
}
StopBenchmarkTiming();
delete[] dst;
}
BENCHMARK(BM_UIOVec)->DenseRange(0, 4);
static void BM_ZFlat(int iters, int arg) {
StopBenchmarkTiming();
// Pick file to process based on "arg"
CHECK_GE(arg, 0);
CHECK_LT(arg, ARRAYSIZE(files));
string contents = ReadTestDataFile(files[arg].filename,
files[arg].size_limit);
char* dst = new char[snappy::MaxCompressedLength(contents.size())];
SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
static_cast<int64>(contents.size()));
StartBenchmarkTiming();
size_t zsize = 0;
while (iters-- > 0) {
snappy::RawCompress(contents.data(), contents.size(), dst, &zsize);
}
StopBenchmarkTiming();
const double compression_ratio =
static_cast<double>(zsize) / std::max<size_t>(1, contents.size());
SetBenchmarkLabel(StringPrintf("%s (%.2f %%)",
files[arg].label, 100.0 * compression_ratio));
VLOG(0) << StringPrintf("compression for %s: %zd -> %zd bytes",
files[arg].label, contents.size(), zsize);
delete[] dst;
}
BENCHMARK(BM_ZFlat)->DenseRange(0, ARRAYSIZE(files) - 1);
} // namespace snappy
int main(int argc, char** argv) {
InitGoogle(argv[0], &argc, &argv, true);
RunSpecifiedBenchmarks();
if (argc >= 2) {
for (int arg = 1; arg < argc; arg++) {
if (FLAGS_write_compressed) {
CompressFile(argv[arg]);
} else if (FLAGS_write_uncompressed) {
UncompressFile(argv[arg]);
} else {
MeasureFile(argv[arg]);
}
}
return 0;
}
return RUN_ALL_TESTS();
}
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