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/*
* SPDX-License-Identifier: GPL-2.0-or-later
* SPDX-FileName: Blob.h
* SPDX-FileContributor: Dmitry Vedenko
*/
#pragma once
#include <cstdint>
struct sqlite3_blob;
namespace audacity::sqlite
{
//! A class representing a BLOB in a SQLite database
class SQLITE_HELPERS_API Blob final
{
friend class Connection;
explicit Blob(sqlite3_blob* blob) noexcept;
public:
~Blob() noexcept;
Blob(const Blob&) = delete;
Blob(Blob&&) noexcept;
Blob& operator=(const Blob&) = delete;
Blob& operator=(Blob&&) noexcept;
//! Returns the size of the BLOB
int64_t Size() const noexcept;
//! Reads up to bufferSize bytes from the BLOB into the buffer at the given offset
int64_t Read(void* buffer, int64_t offset, int64_t bufferSize) const noexcept;
//! Writes up to bufferSize bytes from the buffer into the BLOB at the given offset
int64_t Write(const void* buffer, int64_t offset, int64_t bufferSize) noexcept;
//! Reads up to bufferSize bytes from the BLOB into a container at the given offset
/*!
* If bufferSize is negative, the entire BLOB is read.
* ContainerType must have a resize() method and a data() method.
*/
template<typename ContainerType>
ContainerType Read(int64_t offset = 0, int64_t bufferSize = -1) const
{
if (bufferSize < 0)
bufferSize = Size() - offset;
if (bufferSize <= 0)
return {};
ContainerType buffer;
buffer.resize(bufferSize);
const auto bytesRead = Read(buffer.data(), offset, bufferSize);
buffer.resize(bytesRead);
return buffer;
}
private:
sqlite3_blob* mBlob {};
}; // class Blob
} // namespace audacity::sqlite
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