[coding] Added GZip support.

3 files changed, 150 insertions, 61 deletions

diff --git a/coding/coding_tests/zlib_test.cpp b/coding/coding_tests/zlib_test.cpp
index 6ad1765644..76dfc91e24 100644
--- a/coding/coding_tests/zlib_test.cpp
+++ b/coding/coding_tests/zlib_test.cpp
@@ -2,49 +2,86 @@
 
 #include "coding/zlib.hpp"
 
+#include "base/macros.hpp"
+#include "base/string_utils.hpp"
+
+#include "std/cstdint.hpp"
 #include "std/iterator.hpp"
 #include "std/sstream.hpp"
 #include "std/string.hpp"
+#include "std/utility.hpp"
+#include "std/vector.hpp"
 
 using namespace coding;
 
+using Deflate = ZLib::Deflate;
+using Inflate = ZLib::Inflate;
+
+pair<Deflate::Format, Inflate::Format> const g_combinations[] = {
+    {Deflate::Format::ZLib, Inflate::Format::ZLib},
+    {Deflate::Format::ZLib, Inflate::Format::Both},
+    {Deflate::Format::GZip, Inflate::Format::GZip},
+    {Deflate::Format::GZip, Inflate::Format::Both}};
+
 namespace
 {
-void TestInflateDeflate(string const & original)
+void TestDeflateInflate(string const & original)
 {
-  string compressed;
-  TEST(ZLib::Deflate(original, ZLib::Level::BestCompression, back_inserter(compressed)), ());
+  for (auto const & p : g_combinations)
+  {
+    Deflate const deflate(p.first /* format */, Deflate::Level::BestCompression);
+    Inflate const inflate(p.second /* format */);
 
-  string decompressed;
-  TEST(ZLib::Inflate(compressed, back_inserter(decompressed)), ());
+    string compressed;
+    TEST(deflate(original, back_inserter(compressed)), ());
 
-  TEST_EQUAL(original, decompressed, ());
+    string decompressed;
+    TEST(inflate(compressed, back_inserter(decompressed)), ());
+
+    TEST_EQUAL(original, decompressed, ());
+  }
 }
 
 UNIT_TEST(ZLib_Smoke)
 {
+  Deflate const deflate(Deflate::Format::ZLib, Deflate::Level::BestCompression);
+  Inflate const inflate(Inflate::Format::ZLib);
+
   {
     string s;
-    TEST(!ZLib::Deflate(nullptr, 0, ZLib::Level::BestCompression, back_inserter(s)), ());
-    TEST(!ZLib::Deflate(nullptr, 4, ZLib::Level::BestCompression, back_inserter(s)), ());
-    TEST(!ZLib::Inflate(nullptr, 0, back_inserter(s)), ());
-    TEST(!ZLib::Inflate(nullptr, 4, back_inserter(s)), ());
+    TEST(!deflate(nullptr, 0, back_inserter(s)), ());
+    TEST(!deflate(nullptr, 4, back_inserter(s)), ());
+    TEST(!inflate(nullptr, 0, back_inserter(s)), ());
+    TEST(!inflate(nullptr, 4, back_inserter(s)), ());
   }
 
-  TestInflateDeflate("");
-  TestInflateDeflate("Hello, World!");
+  TestDeflateInflate("");
+  TestDeflateInflate("Hello, World!");
 }
 
 UNIT_TEST(ZLib_Large)
 {
   string original;
-  {
-    ostringstream os;
-    for (size_t i = 0; i < 1000; ++i)
-      os << i;
-    original = os.str();
-  }
+  for (size_t i = 0; i < 1000; ++i)
+    original += strings::to_string(i);
+
+  TestDeflateInflate(original);
+}
+
+UNIT_TEST(GZip_ForeignData)
+{
+  // To get this array of bytes, type following:
+  //
+  // echo -n 'Hello World!' | gzip -c | od -t x1
+  uint8_t const data[] = {0x1f, 0x8b, 0x08, 0x08, 0x6d, 0x55, 0x08, 0x59, 0x00, 0x03, 0x73,
+                          0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x74, 0x78, 0x74, 0x00, 0xf3,
+                          0x48, 0xcd, 0xc9, 0xc9, 0xd7, 0x51, 0x08, 0xcf, 0x2f, 0xca, 0x49,
+                          0x51, 0x04, 0x00, 0xd0, 0xc3, 0x4a, 0xec, 0x0d, 0x00, 0x00, 0x00};
+
+  string s;
 
-  TestInflateDeflate(original);
+  Inflate const inflate(Inflate::Format::GZip);
+  TEST(inflate(data, ARRAY_SIZE(data), back_inserter(s)), ());
+  TEST_EQUAL(s, "Hello, World!", ());
 }
 }  // namespace
diff --git a/coding/zlib.cpp b/coding/zlib.cpp
index 78799f3d8f..9c6850cfb3 100644
--- a/coding/zlib.cpp
+++ b/coding/zlib.cpp
@@ -6,14 +6,15 @@ namespace coding
 {
 namespace
 {
-int ToInt(ZLib::Level level)
+int ToInt(ZLib::Deflate::Level level)
 {
+  using Level = ZLib::Deflate::Level;
   switch (level)
   {
-  case ZLib::Level::NoCompression: return Z_NO_COMPRESSION;
-  case ZLib::Level::BestSpeed: return Z_BEST_SPEED;
-  case ZLib::Level::BestCompression: return Z_BEST_COMPRESSION;
-  case ZLib::Level::DefaultCompression: return Z_DEFAULT_COMPRESSION;
+  case Level::NoCompression: return Z_NO_COMPRESSION;
+  case Level::BestSpeed: return Z_BEST_SPEED;
+  case Level::BestCompression: return Z_BEST_COMPRESSION;
+  case Level::DefaultCompression: return Z_DEFAULT_COMPRESSION;
   }
 }
 }  // namespace
@@ -50,10 +51,20 @@ bool ZLib::Processor::BufferIsFull() const
 }
 
 // ZLib::Deflate -----------------------------------------------------------------------------------
-ZLib::DeflateProcessor::DeflateProcessor(void const * data, size_t size, ZLib::Level level) noexcept
+ZLib::DeflateProcessor::DeflateProcessor(Deflate::Format format, Deflate::Level level,
+                                         void const * data, size_t size) noexcept
   : Processor(data, size)
 {
-  int const ret = deflateInit(&m_stream, ToInt(level));
+  auto bits = MAX_WBITS;
+  switch (format)
+  {
+  case Deflate::Format::ZLib: break;
+  case Deflate::Format::GZip: bits = bits | 16; break;
+  }
+
+  int const ret =
+      deflateInit2(&m_stream, ToInt(level) /* level */, Z_DEFLATED /* method */,
+                   bits /* windowBits */, 8 /* memLevel */, Z_DEFAULT_STRATEGY /* strategy */);
   m_init = (ret == Z_OK);
 }
 
@@ -70,10 +81,18 @@ int ZLib::DeflateProcessor::Process(int flush)
 }
 
 // ZLib::Inflate -----------------------------------------------------------------------------------
-ZLib::InflateProcessor::InflateProcessor(void const * data, size_t size) noexcept
+ZLib::InflateProcessor::InflateProcessor(Inflate::Format format, void const * data,
+                                         size_t size) noexcept
   : Processor(data, size)
 {
-  int const ret = inflateInit(&m_stream);
+  auto bits = MAX_WBITS;
+  switch (format)
+  {
+  case Inflate::Format::ZLib: break;
+  case Inflate::Format::GZip: bits = bits | 16; break;
+  case Inflate::Format::Both: bits = bits | 32; break;
+  }
+  int const ret = inflateInit2(&m_stream, bits);
   m_init = (ret == Z_OK);
 }
 
diff --git a/coding/zlib.hpp b/coding/zlib.hpp
index dba1a59ec7..0f71024629 100644
--- a/coding/zlib.hpp
+++ b/coding/zlib.hpp
@@ -10,7 +10,7 @@
 
 namespace coding
 {
-// Following class is a wrapper around ZLib routines.
+// Following classes are wrappers around ZLib routines.
 //
 // *NOTE* All Inflate() and Deflate() methods may return false in case
 // of errors. In this case the output sequence may be already
@@ -19,43 +19,75 @@ namespace coding
 class ZLib
 {
 public:
-  enum class Level
+  class Inflate
   {
-    NoCompression,
-    BestSpeed,
-    BestCompression,
-    DefaultCompression
+  public:
+    enum class Format
+    {
+      ZLib,
+      GZip,
+      Both
+    };
+
+    explicit Inflate(Format format) noexcept : m_format(format) {}
+
+    template <typename OutIt>
+    bool operator()(void const * data, size_t size, OutIt out) const
+    {
+      if (data == nullptr)
+        return false;
+      InflateProcessor processor(m_format, data, size);
+      return Process(processor, out);
+    }
+
+    template <typename OutIt>
+    bool operator()(string const & s, OutIt out) const
+    {
+      return (*this)(s.c_str(), s.size(), out);
+    }
+
+  private:
+    Format const m_format;
   };
 
-  template <typename OutIt>
-  static bool Deflate(void const * data, size_t size, Level level, OutIt out)
+  class Deflate
   {
-    if (data == nullptr)
-      return false;
-    DeflateProcessor processor(data, size, level);
-    return Process(processor, out);
-  }
+  public:
+    enum class Format
+    {
+      ZLib,
+      GZip
+    };
 
-  template <typename OutIt>
-  static bool Deflate(string const & s, Level level, OutIt out)
-  {
-    return Deflate(s.c_str(), s.size(), level, out);
-  }
+    enum class Level
+    {
+      NoCompression,
+      BestSpeed,
+      BestCompression,
+      DefaultCompression
+    };
 
-  template <typename OutIt>
-  static bool Inflate(void const * data, size_t size, OutIt out)
-  {
-    if (data == nullptr)
-      return false;
-    InflateProcessor processor(data, size);
-    return Process(processor, out);
-  }
+    Deflate(Format format, Level level) noexcept : m_format(format), m_level(level) {}
 
-  template <typename OutIt>
-  static bool Inflate(string const & s, OutIt out)
-  {
-    return Inflate(s.c_str(), s.size(), out);
-  }
+    template <typename OutIt>
+    bool operator()(void const * data, size_t size, OutIt out) const
+    {
+      if (data == nullptr)
+        return false;
+      DeflateProcessor processor(m_format, m_level, data, size);
+      return Process(processor, out);
+    }
+
+    template <typename OutIt>
+    bool operator()(string const & s, OutIt out) const
+    {
+      return (*this)(s.c_str(), s.size(), out);
+    }
+
+  private:
+    Format const m_format;
+    Level const m_level;
+  };
 
 private:
   class Processor
@@ -90,7 +122,8 @@ private:
   class DeflateProcessor final : public Processor
   {
   public:
-    DeflateProcessor(void const * data, size_t size, Level level) noexcept;
+    DeflateProcessor(Deflate::Format format, Deflate::Level level, void const * data,
+                     size_t size) noexcept;
     virtual ~DeflateProcessor() noexcept override;
 
     int Process(int flush);
@@ -101,7 +134,7 @@ private:
   class InflateProcessor final : public Processor
   {
   public:
-    InflateProcessor(void const * data, size_t size) noexcept;
+    InflateProcessor(Inflate::Format format, void const * data, size_t size) noexcept;
     virtual ~InflateProcessor() noexcept override;
 
     int Process(int flush);