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#ifndef SOURCETOOLS_READ_MEMORY_MAPPED_READER_H
#define SOURCETOOLS_READ_MEMORY_MAPPED_READER_H
#include <vector>
#include <string>
#include <algorithm>
#include <sourcetools/core/macros.h>
#include <sourcetools/r/RHeaders.h>
#include <sourcetools/r/RUtils.h>
#ifndef _WIN32
# include <sourcetools/read/posix/FileConnection.h>
# include <sourcetools/read/posix/MemoryMappedConnection.h>
#else
# include <sourcetools/read/windows/FileConnection.h>
# include <sourcetools/read/windows/MemoryMappedConnection.h>
#endif
namespace sourcetools {
namespace detail {
class MemoryMappedReader
{
public:
class VectorReader
{
public:
explicit VectorReader(std::vector<std::string>* pData)
: pData_(pData)
{
}
template <typename T>
void operator()(const T& lhs, const T& rhs)
{
pData_->push_back(std::string(lhs, rhs));
}
private:
std::vector<std::string>* pData_;
};
static bool read(const char* path, std::string* pContent)
{
// Open file connection
FileConnection conn(path);
if (!conn.open())
return false;
// Get size of file
std::size_t size;
if (!conn.size(&size))
return false;
// Early return for empty files
if (UNLIKELY(size == 0))
return true;
// mmap the file
MemoryMappedConnection map(conn, size);
if (!map.open())
return false;
pContent->assign(map, size);
return true;
}
template <typename F>
static bool read_lines(const char* path, F f)
{
FileConnection conn(path);
if (!conn.open())
return false;
// Get size of file
std::size_t size;
if (!conn.size(&size))
return false;
// Early return for empty files
if (UNLIKELY(size == 0))
return true;
// mmap the file
MemoryMappedConnection map(conn, size);
if (!map.open())
return false;
// special case: just a '\n'
bool endsWithNewline = map[size - 1] == '\n';
if (size == 1 && endsWithNewline)
return true;
// Search for newlines
const char* lower = map;
const char* upper = map;
const char* end = map + size;
while (true)
{
upper = std::find(lower, end, '\n');
if (upper == end)
break;
// Handle '\r\n'
int CR = *(upper - 1) == '\r';
upper -= CR;
// Pass to functor
f(lower, upper);
// Update
lower = upper + 1 + CR;
}
// If this file ended with a newline, we're done
if (endsWithNewline)
return true;
// Otherwise, consume one more string, then we're done
f(lower, end);
return true;
}
static bool read_lines(const char* path, std::vector<std::string>* pContent)
{
VectorReader reader(pContent);
return read_lines(path, reader);
}
};
} // namespace detail
} // namespace sourcetools
#endif /* SOURCETOOLS_READ_MEMORY_MAPPED_READER_H */
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