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/*
* DataSource
* (C) 1999-2007 Jack Lloyd
* 2012 Markus Wanner
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_DATA_SRC_H__
#define BOTAN_DATA_SRC_H__
#include <botan/secmem.h>
#include <string>
#include <iosfwd>
namespace Botan {
/**
* This class represents an abstract data source object.
*/
class BOTAN_DLL DataSource
{
public:
/**
* Read from the source. Moves the internal offset so that every
* call to read will return a new portion of the source.
*
* @param out the byte array to write the result to
* @param length the length of the byte array out
* @return length in bytes that was actually read and put
* into out
*/
virtual size_t read(byte out[], size_t length) BOTAN_WARN_UNUSED_RESULT = 0;
virtual bool check_available(size_t n) = 0;
/**
* Read from the source but do not modify the internal
* offset. Consecutive calls to peek() will return portions of
* the source starting at the same position.
*
* @param out the byte array to write the output to
* @param length the length of the byte array out
* @param peek_offset the offset into the stream to read at
* @return length in bytes that was actually read and put
* into out
*/
virtual size_t peek(byte out[], size_t length, size_t peek_offset) const BOTAN_WARN_UNUSED_RESULT = 0;
/**
* Test whether the source still has data that can be read.
* @return true if there is still data to read, false otherwise
*/
virtual bool end_of_data() const = 0;
/**
* return the id of this data source
* @return std::string representing the id of this data source
*/
virtual std::string id() const { return ""; }
/**
* Read one byte.
* @param out the byte to read to
* @return length in bytes that was actually read and put
* into out
*/
size_t read_byte(byte& out);
/**
* Peek at one byte.
* @param out an output byte
* @return length in bytes that was actually read and put
* into out
*/
size_t peek_byte(byte& out) const;
/**
* Discard the next N bytes of the data
* @param N the number of bytes to discard
* @return number of bytes actually discarded
*/
size_t discard_next(size_t N);
/**
* @return number of bytes read so far.
*/
virtual size_t get_bytes_read() const = 0;
DataSource() {}
virtual ~DataSource() {}
DataSource& operator=(const DataSource&) = delete;
DataSource(const DataSource&) = delete;
};
/**
* This class represents a Memory-Based DataSource
*/
class BOTAN_DLL DataSource_Memory : public DataSource
{
public:
size_t read(byte[], size_t) override;
size_t peek(byte[], size_t, size_t) const override;
bool check_available(size_t n) override;
bool end_of_data() const override;
/**
* Construct a memory source that reads from a string
* @param in the string to read from
*/
explicit DataSource_Memory(const std::string& in);
/**
* Construct a memory source that reads from a byte array
* @param in the byte array to read from
* @param length the length of the byte array
*/
DataSource_Memory(const byte in[], size_t length) :
m_source(in, in + length), m_offset(0) {}
/**
* Construct a memory source that reads from a secure_vector
* @param in the MemoryRegion to read from
*/
explicit DataSource_Memory(const secure_vector<byte>& in) :
m_source(in), m_offset(0) {}
/**
* Construct a memory source that reads from a std::vector
* @param in the MemoryRegion to read from
*/
explicit DataSource_Memory(const std::vector<byte>& in) :
m_source(in.begin(), in.end()), m_offset(0) {}
size_t get_bytes_read() const override { return m_offset; }
private:
secure_vector<byte> m_source;
size_t m_offset;
};
#if defined(BOTAN_TARGET_OS_HAS_FILESYSTEM)
/**
* This class represents a Stream-Based DataSource.
*/
class BOTAN_DLL DataSource_Stream : public DataSource
{
public:
size_t read(byte[], size_t) override;
size_t peek(byte[], size_t, size_t) const override;
bool check_available(size_t n) override;
bool end_of_data() const override;
std::string id() const override;
DataSource_Stream(std::istream&,
const std::string& id = "<std::istream>");
/**
* Construct a Stream-Based DataSource from file
* @param file the name of the file
* @param use_binary whether to treat the file as binary or not
*/
DataSource_Stream(const std::string& file, bool use_binary = false);
DataSource_Stream(const DataSource_Stream&) = delete;
DataSource_Stream& operator=(const DataSource_Stream&) = delete;
~DataSource_Stream();
size_t get_bytes_read() const override { return m_total_read; }
private:
const std::string m_identifier;
std::istream* m_source_p;
std::istream& m_source;
size_t m_total_read;
};
#endif
}
#endif
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