// bslim_fuzzdataview.h -*-C++-*-
#ifndef INCLUDED_BSLIM_FUZZDATAVIEW
#define INCLUDED_BSLIM_FUZZDATAVIEW
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide a view of a buffer of fuzz data bytes.
//
//@CLASSES:
// bslim::FuzzDataView: reference-semantic type for fuzz data
//
//@SEE_ALSO: bslim_fuzzutil
//
//@DESCRIPTION: This component defines a reference-semantic class,
// 'bslim::FuzzDataView', providing a view to a non-modifiable buffer of fuzz
// data obtained from a fuzz testing harness (e.g., 'libFuzzer').
//
// See {http://bburl/BDEFuzzTesting} for details on how to build and run with
// fuzz testing enabled.
//
// Typically, this class is intended to be employed by a utility that takes an
// object of this class as an in-out parameter, consumes the bytes (updating
// the view so that the bytes are not used again), and returns objects of the
// type requested.
//
///Usage
///-----
// This section illustrates intended use of this component.
//
///Example 1: Creating a 'bsl::string'
///- - - - - - - - - - - - - - - - - -
// The following example demonstrates how to create a 'bsl::string' object from
// a 'FuzzDataView'.
//
// First, we construct a 'FuzzDataView' object, 'view0', from an array of
// bytes:
//..
// const bsl::uint8_t data[] = {0x8A, 0x19, 0x0D, 0x44, 0x37, 0x0D,
// 0x38, 0x5E, 0x9B, 0xAA, 0xF3, 0xDA};
//
// bslim::FuzzDataView view0(data, sizeof(data));
//
// assert(12 == view0.length());
//..
// Next, we take the first 3 bytes from 'view0' and store them in a new
// 'FuzzDataView' object, 'view1':
//..
// bslim::FuzzDataView view1 = view0.removePrefix(3);
//
// assert(3 == view1.length());
// assert(9 == view0.length());
//..
// We confirm that 'removePrefix(3)' removed 3 bytes from 'view0' and that
// 'view1' has length 3.
//
// Then, we create a 'bsl::string' object from 'view1':
//..
// bsl::string s1(view1.begin(), view1.end());
//
// assert(3 == s1.length());
//..
// Finally, we create another 'bsl::string' with the remaining bytes of
// 'view0':
//..
// bsl::string s2(view0.begin(), view0.end());
//
// assert(9 == s2.length());
//..
#include <bslscm_version.h>
#include <bsls_assert.h>
#include <bsl_algorithm.h> // min
#include <bsl_cstddef.h> // size_t
#include <bsl_cstdint.h> // uint8_t
namespace BloombergLP {
namespace bslim {
// ==================
// class FuzzDataView
// ==================
class FuzzDataView {
// This type represents a view of a buffer of bytes provided by a fuzz
// testing harness.
private:
// DATA
const bsl::uint8_t *d_data_p; // pointer to the data
bsl::size_t d_length; // length of the view
public:
// CREATORS
FuzzDataView(const bsl::uint8_t *data, bsl::size_t size);
// Create a 'FuzzDataView' object from the specified fuzz 'data' and
// 'size'. The behavior is undefined unless 'data || (0 == size)'.
// FuzzDataView(const FuzzDataView& original) = default;
// Create a 'FuzzDataView' having the value of the specified 'original'
// 'FuzzDataView'. Note that this trivial copy constructor is
// generated by the compiler.
// ~FuzzDataView() = default;
// Destroy this 'FuzzDataView' object. Note that this trivial
// destructor is generated by the compiler.
// MANIPULATORS
// FuzzDataView &operator=(const FuzzDataView& rhs) = default;
// Assign to this FuzzDataView the value of the specified 'rhs'
// 'FuzzDataView', and return a reference providing modifiable access
// to this object. Note that this trivial assignment operation is
// generated by the compiler.
FuzzDataView removePrefix(bsl::size_t numBytes);
// Remove the specified initial 'numBytes' from this view if
// 'numBytes <= length()' and remove 'length()' bytes otherwise; return
// a view to the bytes that were removed. Note that this method will
// decrease the length of this view by 'min(numBytes, length())' bytes.
FuzzDataView removeSuffix(bsl::size_t numBytes);
// Remove the specified last 'numBytes' from this view if
// 'numBytes <= length()' and remove 'length()' bytes otherwise; return
// a view to the bytes that were removed. Note that this method will
// decrease the length of this view by 'min(numBytes, length())' bytes.
// ACCESSORS
const bsl::uint8_t *begin() const;
// Return a const pointer to the beginning of the buffer.
const bsl::uint8_t *end() const;
// Return a const pointer to the end of the buffer.
bsl::size_t length() const;
// Return the length in bytes of the buffer.
const bsl::uint8_t *data() const;
// Return a pointer to the beginning of the buffer.
};
// ============================================================================
// INLINE DEFINITIONS
// ============================================================================
// ------------------
// class FuzzDataView
// ------------------
// CREATORS
inline
FuzzDataView::FuzzDataView(const bsl::uint8_t *data, bsl::size_t size)
: d_data_p(data)
, d_length(size)
{
BSLS_ASSERT(data || (0 == size));
}
// MANIPULATORS
inline
FuzzDataView FuzzDataView::removePrefix(bsl::size_t numBytes)
{
FuzzDataView prefix(d_data_p, bsl::min(numBytes, length()));
d_data_p += prefix.length();
d_length -= prefix.length();
return prefix;
}
inline
FuzzDataView FuzzDataView::removeSuffix(bsl::size_t numBytes)
{
bsl::size_t num = bsl::min(numBytes, length());
FuzzDataView suffix(end() - num, num);
d_length -= num;
return suffix;
}
// ACCESSORS
inline
const bsl::uint8_t* FuzzDataView::begin() const
{
return d_data_p;
}
inline
const bsl::uint8_t* FuzzDataView::end() const
{
return d_data_p + d_length;
}
inline
bsl::size_t FuzzDataView::length() const
{
return d_length;
}
inline
const bsl::uint8_t *FuzzDataView::data() const
{
return d_data_p;
}
} // close package namespace
} // close enterprise namespace
#endif
// ----------------------------------------------------------------------------
// Copyright 2021 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 ----------------------------------