db/dbmi_base/xdr.c

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/*!
  \file lib/db/dbmi_base/xdr.c
  
  \brief DBMI Library (base) - external data representation
  
  (C) 1999-2009, 2011 by the GRASS Development Team
  
  This program is free software under the GNU General Public License
  (>=v2). Read the file COPYING that comes with GRASS for details.
  
  \author Joel Jones (CERL/UIUC), Radim Blazek, Brad Douglas, Markus Neteler
  \author Doxygenized by Martin Landa <landa.martin gmail.com> (2011)
*/

#include "xdr.h"

#ifdef __MINGW32__
#define USE_STDIO 0
#define USE_READN 1
#else
#define USE_STDIO 1
#define USE_READN 0
#endif

#ifndef USE_STDIO
#include <unistd.h>
#endif

static FILE *_send, *_recv;

#if USE_READN

static ssize_t readn(int fd, void *buf, size_t count)
{
    ssize_t total = 0;

    while (total < count) {
        ssize_t n = read(fd, (char *)buf + total, count - total);

        if (n < 0)
            return n;
        if (n == 0)
            break;
        total += n;
    }

    return total;
}

static ssize_t writen(int fd, const void *buf, size_t count)
{
    ssize_t total = 0;

    while (total < count) {
        ssize_t n = write(fd, (const char *)buf + total, count - total);

        if (n < 0)
            return n;
        if (n == 0)
            break;
        total += n;
    }

    return total;
}

#endif

/*!
  \brief ?
  
  \param send
  \param recv
*/
void db__set_protocol_fds(FILE * send, FILE * recv)
{
    _send = send;
    _recv = recv;
}

/*!
  \brief ?

  \param buf
  \param size

  \return
*/
int db__send(const void *buf, size_t size)
{
#if USE_STDIO
    return fwrite(buf, 1, size, _send) == size;
#elif USE_READN
    return writen(fileno(_send), buf, size) == size;
#else
    return write(fileno(_send), buf, size) == size;
#endif
}

int db__recv(void *buf, size_t size)
{
#if USE_STDIO
#ifdef USE_BUFFERED_IO
    fflush(_send);
#endif
    return fread(buf, 1, size, _recv) == size;
#elif USE_READN
    return readn(fileno(_recv), buf, size) == size;
#else
    return read(fileno(_recv), buf, size) == size;
#endif
}