// Copyright 2011 Google Inc.
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#include "utils/stream.hpp"

#include <istream>
#include <sstream>

#include "utils/format/macros.hpp"
#include "utils/sanity.hpp"


/// Gets the length of a stream.
///
/// \param is The input stream for which to calculate its length.
///
/// \return The length of the stream.  This is of size_t type instead of
/// directly std::streampos to simplify the caller.  Some systems do not
/// support comparing a std::streampos directly to an integer (see
/// NetBSD 1.5.x), which is what we often want to do.
///
/// \throw std::exception If calculating the length fails due to a stream error.
std::size_t
utils::stream_length(std::istream& is)
{
    const std::streampos current_pos = is.tellg();
    try {
        is.seekg(0, std::ios::end);
        const std::streampos length = is.tellg();
        is.seekg(current_pos, std::ios::beg);
        return static_cast< std::size_t >(length);
    } catch (...) {
        is.seekg(current_pos, std::ios::beg);
        throw;
    }
}


/// Reads the whole contents of a stream into memory.
///
/// \param input The input stream from which to read.
///
/// \return A plain string containing the raw contents of the file.
std::string
utils::read_stream(std::istream& input)
{
    std::ostringstream buffer;

    char tmp[1024];
    while (input.good()) {
        input.read(tmp, sizeof(tmp));
        if (input.good() || input.eof()) {
            buffer.write(tmp, input.gcount());
        }
    }

    return buffer.str();
}