proxygen::ZlibStreamDecompressor Class Reference

#include <ZlibStreamDecompressor.h>

Public Member Functions
	ZlibStreamDecompressor (ZlibCompressionType type)
	ZlibStreamDecompressor ()
	~ZlibStreamDecompressor ()
void	init (ZlibCompressionType type)
std::unique_ptr< folly::IOBuf >	decompress (const folly::IOBuf *in)
int	getStatus ()
bool	hasError ()
bool	finished ()

Private Attributes
ZlibCompressionType	type_ {ZlibCompressionType::NONE}
z_stream	zlibStream_
int	status_ {-1}

Detailed Description

Definition at line 31 of file ZlibStreamDecompressor.h.

Constructor & Destructor Documentation

proxygen::ZlibStreamDecompressor::ZlibStreamDecompressor ( ZlibCompressionType  type )

explicit

Definition at line 46 of file ZlibStreamDecompressor.cpp.

References init().

    : type_(ZlibCompressionType::NONE), status_(Z_OK) {
  init(type);
}

proxygen::ZlibStreamDecompressor::ZlibStreamDecompressor ( )

inline

Definition at line 35 of file ZlibStreamDecompressor.h.

References folly::init().

{ }

proxygen::ZlibStreamDecompressor::~ZlibStreamDecompressor

(

)

Definition at line 51 of file ZlibStreamDecompressor.cpp.

References proxygen::NONE, status_, type_, and zlibStream_.

                                                {
  if (type_ != ZlibCompressionType::NONE) {
    status_ = inflateEnd(&zlibStream_);
  }
}

Member Function Documentation

std::unique_ptr< IOBuf > proxygen::ZlibStreamDecompressor::decompress

(

const folly::IOBuf *

in

)

Definition at line 57 of file ZlibStreamDecompressor.cpp.

References proxygen::ERROR, folly::IOBuf::next(), status_, uint8_t, and zlibStream_.

Referenced by ZlibServerFilterTest::exercise_compression().

                                                                       {
  auto out = IOBuf::create(FLAGS_zlib_buffer_growth);
  auto appender = folly::io::Appender(out.get(),
      FLAGS_zlib_buffer_growth);

  const IOBuf* crtBuf = in;
  size_t offset = 0;
  while (true) {
    // Advance to the next IOBuf if necessary
    DCHECK_GE(crtBuf->length(), offset);
    if (crtBuf->length() == offset) {
      crtBuf = crtBuf->next();
      offset = 0;
      if (crtBuf == in) {
        // We hit the end of the IOBuf chain, and are done.
        break;
      }
    }

    if (status_ == Z_STREAM_END) {
      // we convert this into a stream error
      status_ = Z_STREAM_ERROR;
      // we should probably bump up a counter here
      LOG(ERROR) << "error uncompressing buffer: reached end of zlib data "
        "before the end of the buffer";
      return nullptr;
    }

    // Ensure there is space in the output IOBuf
    appender.ensure(FLAGS_zlib_buffer_minsize);
    DCHECK_GT(appender.length(), 0);

    const size_t origAvailIn = crtBuf->length() - offset;
    zlibStream_.next_in = const_cast<uint8_t*>(crtBuf->data() + offset);
    zlibStream_.avail_in = origAvailIn;
    zlibStream_.next_out = appender.writableData();
    zlibStream_.avail_out = appender.length();
    status_ = inflate(&zlibStream_, Z_PARTIAL_FLUSH);
    if (status_ != Z_OK && status_ != Z_STREAM_END) {
      LOG(INFO) << "error uncompressing buffer: r=" << status_;
      return nullptr;
    }

    // Adjust the input offset ahead
    auto inConsumed = origAvailIn - zlibStream_.avail_in;
    offset += inConsumed;
    // Move output buffer ahead
    auto outMove = appender.length() - zlibStream_.avail_out;
    appender.append(outMove);
  }

  return out;
}

bool proxygen::ZlibStreamDecompressor::finished ( )

inline

Definition at line 47 of file ZlibStreamDecompressor.h.

{ return status_ == Z_STREAM_END; }

int proxygen::ZlibStreamDecompressor::getStatus ( )

inline

Definition at line 43 of file ZlibStreamDecompressor.h.

Referenced by ZlibServerFilterTest::exercise_compression().

{ return status_; }

bool proxygen::ZlibStreamDecompressor::hasError ( )

inline

Definition at line 45 of file ZlibStreamDecompressor.h.

Referenced by ZlibServerFilterTest::exercise_compression().

{ return status_ != Z_OK && status_ != Z_STREAM_END; }

void proxygen::ZlibStreamDecompressor::init

(

ZlibCompressionType

type

)

Definition at line 29 of file ZlibStreamDecompressor.cpp.

References proxygen::NONE, status_, type, type_, and zlibStream_.

Referenced by ZlibStreamDecompressor().

                                                          {
  DCHECK(type_ == ZlibCompressionType::NONE) << "Must be uninitialized";
  type_ = type;
  status_ = Z_OK;
  zlibStream_.zalloc = Z_NULL;
  zlibStream_.zfree = Z_NULL;
  zlibStream_.opaque = Z_NULL;
  zlibStream_.total_in = 0;
  zlibStream_.next_in = Z_NULL;
  zlibStream_.avail_in = 0;
  zlibStream_.avail_out = 0;
  zlibStream_.next_out = Z_NULL;

  DCHECK(type != ZlibCompressionType::NONE);
  status_ = inflateInit2(&zlibStream_, static_cast<int>(type_));
}

Member Data Documentation

int proxygen::ZlibStreamDecompressor::status_ {-1}

private

Definition at line 52 of file ZlibStreamDecompressor.h.

Referenced by decompress(), init(), and ~ZlibStreamDecompressor().

ZlibCompressionType proxygen::ZlibStreamDecompressor::type_ {ZlibCompressionType::NONE}

private

Definition at line 50 of file ZlibStreamDecompressor.h.

Referenced by init(), and ~ZlibStreamDecompressor().

z_stream proxygen::ZlibStreamDecompressor::zlibStream_

private

Definition at line 51 of file ZlibStreamDecompressor.h.

Referenced by decompress(), init(), and ~ZlibStreamDecompressor().

---

The documentation for this class was generated from the following files:

• proxygen/lib/utils/ZlibStreamDecompressor.h
• proxygen/lib/utils/ZlibStreamDecompressor.cpp