// bdlbb_blobstreambuf.h -*-C++-*-
// ----------------------------------------------------------------------------
// NOTICE
//
// This component is not up to date with current BDE coding standards, and
// should not be used as an example for new development.
// ----------------------------------------------------------------------------
#ifndef INCLUDED_BDLBB_BLOBSTREAMBUF
#define INCLUDED_BDLBB_BLOBSTREAMBUF
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide blob implementing the 'streambuf' interface.
//
//@CLASSES:
// bdlbb::InBlobStreamBuf: 'bdlbb::Blob' input 'streambuf'
// bdlbb::OutBlobStreamBuf: 'bdlbb::Blob' output 'streambuf'
//
//@SEE_ALSO: bdlbb_blob
//
//@DESCRIPTION: This component implements the input and output
// 'bsl::basic_streambuf' protocol using a user-supplied 'bdlbb::Blob'. Method
// names necessarily correspond to the protocol-specified method names. Refer
// to the C++ Standard, Section 27.5.2, for a full specification of the
// interface.
//
// A 'bdlbb::Blob' is an indexed sequence of 'bdlbb::BlobBuffer' of potentially
// different sizes. The number of buffers in the sequence can increase or
// decrease, but the order of the buffers cannot change. Therefore, the blob
// behaves logically as a single indexed buffer. 'bdlbb::InBlobStreamBuf' and
// 'bdlbb::OutBlobStreamBuf' can therefore respectively read from and write to
// this buffer as if there were a single continuous index.
#include <bdlscm_version.h>
#include <bdlbb_blob.h>
#include <bsls_assert.h>
#include <bsls_review.h>
#include <bsl_ios.h> // for 'bsl::streamsize'
#include <bsl_streambuf.h>
#include <bsl_cstddef.h> // bsl::size_t
namespace BloombergLP {
namespace bdlbb { class Blob; }
namespace bdlbb {
// =====================
// class InBlobStreamBuf
// =====================
class InBlobStreamBuf : public bsl::streambuf {
// This class implements the input functionality of the 'basic_streambuf'
// protocol, using a client-supplied 'bdlbb::Blob'.
// PRIVATE TYPES
typedef bsl::ios_base ios_base;
// DATA
const bdlbb::Blob *d_blob_p; // "streamed" blob (held)
int d_getBufferIndex; // index of current buffer
int d_previousBuffersLength; // length of buffers before the
// current one
// NOT IMPLEMENTED
InBlobStreamBuf(const InBlobStreamBuf&);
InBlobStreamBuf& operator=(const InBlobStreamBuf&);
private:
// PRIVATE MANIPULATORS
void setGetPosition(bsl::size_t position);
// Set the current location to the specified 'position'.
// PRIVATE ACCESSORS
int checkInvariant() const;
// Check this object's invariant.
protected:
// PROTECTED VIRTUAL FUNCTIONS
virtual int_type overflow(int_type c = bsl::streambuf::traits_type::eof());
// Return 'traits_type::eof()' unconditionally.
virtual int_type pbackfail(
int_type c = bsl::streambuf::traits_type::eof());
// Adjust the underlying blob and put the optionally specified
// character 'c' at the newly valid 'gptr()'. Return 'c' (or
// '~traits_type::eof' if 'c == traits_type::eof') on success, and
// 'traits_type::eof()' otherwise.
virtual pos_type seekoff(
off_type offset,
bsl::ios_base::seekdir fixedPosition,
bsl::ios_base::openmode which = bsl::ios_base::in | bsl::ios_base::out);
// Set the location from which the next I/O operation indicated by the
// optionally specified 'which' mode will occur to the specified
// 'offset' position from the location indicated by the specified
// 'fixedPosition'. Return the new offset on success, and
// 'off_type(-1)' otherwise. 'offset' may be negative. Note that this
// method will fail if 'bsl::ios_base::out' is set.
virtual pos_type seekpos(
pos_type position,
bsl::ios_base::openmode which = bsl::ios_base::in | bsl::ios_base::out);
// Set the location from which the next I/O operation indicated by the
// optionally specified 'which' mode will occur to the specified
// 'position'. Return 'position' on success, and 'off_type(-1)'
// otherwise. Note that this method will fail if 'bsl::ios_base::out'
// is set.
virtual bsl::streamsize showmanyc();
// Return the number of characters currently available for reading from
// this stream buffer, or 0 if there are none.
virtual int sync();
// Return 0 unconditionally.
virtual int_type underflow();
// Adjust the underlying blob so that the next read position is valid.
// Return the character at 'gptr()' on success and 'traits_type::eof()'
// otherwise.
virtual bsl::streamsize xsgetn(char_type *destination,
bsl::streamsize numChars);
// Read the specified 'numChars' to the specified 'destination'.
// Return the number of characters successfully read. The behavior is
// undefined unless 0 <= 'numChars'.
virtual bsl::streamsize xsputn(const char_type *source,
bsl::streamsize numChars);
// Return 0 unconditionally.
public:
// CREATORS
explicit InBlobStreamBuf(const bdlbb::Blob *blob);
// Create a 'BlobStreamBuf' using the specified 'blob'. The behavior
// is undefined unless 'blob' remains valid and externally unmodified
// for the lifetime of this 'streambuf'.
~InBlobStreamBuf();
// Destroy this stream buffer.
// MANIPULATORS
void reset(const bdlbb::Blob *blob = 0);
// Reset the get areas. Optionally set the underlying 'bdlbb::Blob'
// value to the optionally specified 'blob' if 'blob' is not 0. The
// behavior is undefined unless 'blob' remains valid and externally
// unmodified for the lifetime of this 'streambuf'.
// ACCESSORS
int currentBufferIndex() const;
// Return the index of the current buffer. The behavior is undefined
// unless the "streamed" blob has at least one buffer.
const bdlbb::Blob *data() const;
// Return the address of the blob held by this stream buffer.
int previousBuffersLength() const;
// Return the number of bytes contained in the buffers located before
// the current one. The behavior is undefined unless the "streamed"
// blob has at least one buffer.
};
// ======================
// class OutBlobStreamBuf
// ======================
class OutBlobStreamBuf : public bsl::streambuf {
// This class implements the output functionality of the 'basic_streambuf'
// protocol, using a client-supplied 'bdlbb::Blob'.
// PRIVATE TYPES
typedef bsl::ios_base ios_base;
// DATA
bdlbb::Blob *d_blob_p; // "streamed" blob (held)
int d_putBufferIndex; // index of current buffer
int d_previousBuffersLength; // length of buffers before
// NOT IMPLEMENTED
OutBlobStreamBuf(const OutBlobStreamBuf&);
OutBlobStreamBuf& operator=(const OutBlobStreamBuf&);
private:
// PRIVATE MANIPULATORS
void setPutPosition(bsl::size_t position);
// Set the current location to the specified 'position'.
// PRIVATE ACCESSORS
int checkInvariant() const;
// Check this object's invariants and return 0.
protected:
// PROTECTED VIRTUAL FUNCTIONS
virtual int_type overflow(int_type c = bsl::streambuf::traits_type::eof());
// Append the optionally specified character 'c' to this streambuf, and
// return 'c'. By default, 'traits_type::eof()' is appended.
virtual int_type pbackfail(
int_type c = bsl::streambuf::traits_type::eof());
// Return 'traits_type::eof()' unconditionally.
virtual pos_type seekoff(
off_type offset,
bsl::ios_base::seekdir fixedPosition,
bsl::ios_base::openmode which = bsl::ios_base::in | bsl::ios_base::out);
// Set the location from which the next I/O operation indicated by the
// optionally specified 'which' mode will occur to the specified
// 'offset' position from the location indicated by the specified
// 'fixedPosition'. Return the new offset on success, and
// 'off_type(-1)' otherwise. 'offset' may be negative. Note that this
// method will fail if 'bsl::ios_base::in' is set.
virtual pos_type seekpos(
pos_type position,
bsl::ios_base::openmode which = bsl::ios_base::in | bsl::ios_base::out);
// Set the location from which the next I/O operation indicated by the
// optionally specified 'which' mode will occur to the specified
// 'position'. Return 'position' on success, and 'off_type(-1)'
// otherwise. Note that this method will fail if 'bsl::ios_base::in'
// is set.
virtual bsl::streamsize showmanyc();
// Return 0 unconditionally.
virtual int sync();
// Synchronize the put position in the blob of this stream buffer.
// Return 0 unconditionally.
virtual int_type underflow();
// Return 'traits_type::eof()' unconditionally.
virtual bsl::streamsize xsgetn(char_type *destination,
bsl::streamsize numChars);
// Return 0 unconditionally.
virtual bsl::streamsize xsputn(const char_type *source,
bsl::streamsize numChars);
// Copy the specified 'numChars' from the specified 'source' to the
// blob held by this streambuf, starting at the current put area
// location. The behavior is undefined unless 0 <= 'numChars'.
public:
// CREATORS
explicit OutBlobStreamBuf(bdlbb::Blob *blob);
// Create a 'OutBlobStreamBuf' using the specified 'blob', and set the
// location at which the next write operation will occur to
// 'blob->length()'. The behavior is undefined unless 'blob' remains
// valid and externally unmodified for the lifetime of this
// 'streambuf'.
~OutBlobStreamBuf();
// Destroy this stream buffer.
// MANIPULATORS
bdlbb::Blob *data();
// Return the address of the blob held by this stream buffer.
void reset(bdlbb::Blob *blob = 0);
// Reset the put position of this buffer to the first location,
// available for writing in the underlying 'bdlbb::Blob'. Optionally
// specify a 'blob' used to change current underlying 'bdlbb::Blob'
// value for. The behavior is undefined unless 'blob' remains valid
// and externally unmodified for the lifetime of this 'streambuf'.
// ACCESSORS
int currentBufferIndex() const;
// Return the index of the current buffer. The behavior is undefined
// unless the "streamed" blob has at least one buffer.
const bdlbb::Blob *data() const;
// Return the address of the blob held by this stream buffer.
int previousBuffersLength() const;
// Return the number of bytes contained in the buffers located before
// the current one. The behavior is undefined unless the "streamed"
// blob has at least one buffer.
};
// ============================================================================
// INLINE DEFINITIONS
// ============================================================================
// =====================
// class InBlobStreamBuf
// =====================
// MANIPULATORS
inline
void InBlobStreamBuf::reset(const bdlbb::Blob *blob)
{
if (blob) {
d_blob_p = blob;
d_getBufferIndex = 0;
d_previousBuffersLength = 0;
setg(0, 0, 0);
if (0 == d_blob_p->length()) {
return; // RETURN
}
}
setGetPosition(0);
}
// ACCESSORS
inline
int InBlobStreamBuf::currentBufferIndex() const
{
BSLS_ASSERT(d_getBufferIndex < d_blob_p->numBuffers());
return d_getBufferIndex;
}
inline
const bdlbb::Blob *InBlobStreamBuf::data() const
{
return d_blob_p;
}
inline
int InBlobStreamBuf::previousBuffersLength() const
{
return d_previousBuffersLength;
}
// ======================
// class OutBlobStreamBuf
// ======================
// MANIPULATORS
inline
bdlbb::Blob *OutBlobStreamBuf::data()
{
return d_blob_p;
}
inline
void OutBlobStreamBuf::reset(bdlbb::Blob *blob)
{
if (blob) {
d_blob_p = blob;
d_putBufferIndex = 0;
d_previousBuffersLength = 0;
setp(0, 0);
if (0 == d_blob_p->totalSize()) {
return; // RETURN
}
}
setPutPosition(d_blob_p->length());
}
// ACCESSORS
inline
int OutBlobStreamBuf::currentBufferIndex() const
{
BSLS_ASSERT(d_putBufferIndex < d_blob_p->numBuffers());
return d_putBufferIndex;
}
inline
const bdlbb::Blob *OutBlobStreamBuf::data() const
{
return d_blob_p;
}
inline
int OutBlobStreamBuf::previousBuffersLength() const
{
return d_previousBuffersLength;
}
} // close package namespace
} // close enterprise namespace
#endif
// ----------------------------------------------------------------------------
// Copyright 2018 Bloomberg Finance L.P.
//
// 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.
// ----------------------------- END-OF-FILE ----------------------------------