binio.cpp

/******************************************************/
/*                                                    */
/* binio.cpp - binary input/output                    */
/*                                                    */
/******************************************************/
/* Copyright 2019 Pierre Abbat.
 * This file is part of PerfectTIN.
 *
 * PerfectTIN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * PerfectTIN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License and Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * and Lesser General Public License along with PerfectTIN. If not, see
 * <http://www.gnu.org/licenses/>.
 */
#include <cstring>
#include "binio.h"
#include "config.h"

using namespace std;

void endianflip(void *addr,int n)
{
  int i;
  char *addr2;
  addr2=(char *)addr;
  for (i=0;i<n/2;i++)
  {
    addr2[i]^=addr2[n-1-i];
    addr2[n-1-i]^=addr2[i];
    addr2[i]^=addr2[n-1-i];
  }
}

void writebeshort(std::ostream &file,short i)
{
  char buf[2];
  *(short *)buf=i;
#ifndef BIGENDIAN
  endianflip(buf,2);
#endif
  file.write(buf,2);
}

void writeleshort(std::ostream &file,short i)
{
  char buf[2];
  *(short *)buf=i;
#ifdef BIGENDIAN
  endianflip(buf,2);
#endif
  file.write(buf,2);
}

short readbeshort(std::istream &file)
{
  char buf[2];
  file.read(buf,2);
#ifndef BIGENDIAN
  endianflip(buf,2);
#endif
  return *(short *)buf;
}

short readleshort(std::istream &file)
{
  char buf[2];
  file.read(buf,2);
#ifdef BIGENDIAN
  endianflip(buf,2);
#endif
  return *(short *)buf;
}

void writebeint(std::ostream &file,int i)
{
  char buf[4];
  *(int *)buf=i;
#ifndef BIGENDIAN
  endianflip(buf,4);
#endif
  file.write(buf,4);
}

void writeleint(std::ostream &file,int i)
{
  char buf[4];
  *(int *)buf=i;
#ifdef BIGENDIAN
  endianflip(buf,4);
#endif
  file.write(buf,4);
}

int readbeint(std::istream &file)
{
  char buf[4];
  file.read(buf,4);
#ifndef BIGENDIAN
  endianflip(buf,4);
#endif
  return *(int *)buf;
}

int readleint(std::istream &file)
{
  char buf[4];
  file.read(buf,4);
#ifdef BIGENDIAN
  endianflip(buf,4);
#endif
  return *(int *)buf;
}

void writebelong(std::ostream &file,long long i)
{
  char buf[8];
  *(long long *)buf=i;
#ifndef BIGENDIAN
  endianflip(buf,8);
#endif
  file.write(buf,8);
}

void writelelong(std::ostream &file,long long i)
{
  char buf[8];
  *(long long *)buf=i;
#ifdef BIGENDIAN
  endianflip(buf,8);
#endif
  file.write(buf,8);
}

long long readbelong(std::istream &file)
{
  char buf[8];
  file.read(buf,8);
#ifndef BIGENDIAN
  endianflip(buf,8);
#endif
  return *(long long *)buf;
}

long long readlelong(std::istream &file)
{
  char buf[8];
  file.read(buf,8);
#ifdef BIGENDIAN
  endianflip(buf,8);
#endif
  return *(long long *)buf;
}

float readbefloat(std::istream &file)
{
  char buf[4];
  file.read(buf,4);
#ifndef BIGENDIAN
  endianflip(buf,4);
#endif
  return *(float *)buf;
}

float readlefloat(std::istream &file)
{
  char buf[4];
  file.read(buf,4);
#ifdef BIGENDIAN
  endianflip(buf,4);
#endif
  return *(float *)buf;
}

void writebefloat(std::ostream &file,float f)
{
  char buf[4];
  *(float *)buf=f;
#ifndef BIGENDIAN
  endianflip(buf,4);
#endif
  file.write(buf,4);
}

void writelefloat(std::ostream &file,float f)
{
  char buf[4];
  *(float *)buf=f;
#ifdef BIGENDIAN
  endianflip(buf,4);
#endif
  file.write(buf,4);
}

void writebedouble(std::ostream &file,double f)
{
  char buf[8];
  *(double *)buf=f;
#ifndef BIGENDIAN
  endianflip(buf,8);
#endif
  file.write(buf,8);
}

void writeledouble(std::ostream &file,double f)
{
  char buf[8];
  *(double *)buf=f;
#ifdef BIGENDIAN
  endianflip(buf,8);
#endif
  file.write(buf,8);
}

double readbedouble(std::istream &file)
{
  char buf[8];
  file.read(buf,8);
#ifndef BIGENDIAN
  endianflip(buf,8);
#endif
  return *(double *)buf;
}

double readledouble(std::istream &file)
{
  char buf[8];
  file.read(buf,8);
#ifdef BIGENDIAN
  endianflip(buf,8);
#endif
  return *(double *)buf;
}

void writegeint(std::ostream &file,int i)
/* Numbers in Decisite's geoid files are in 65536ths of a meter and are less than 110 m
 * (7208960) in absolute value. They are encoded as follows:
 * 20					80 00 00 00, which means NaN
 * gg where gg is 00-1f			00 00 00 gg
 * gg where gg is 21-3f			ff ff ff hh where hh is gg+c0
 * gg xx where gg is 40-5f		00 00 hh xx + 20 where hh is gg-40
 * gg xx where gg is 60-7f		ff ff hh xx - 1f where hh is gg+80
 * gg xx xx where gg is 80-9f		00 hh xx xx + 2020 where hh is gg-80
 * gg xx xx where gg is a0-bf		ff hh xx xx - 201f where hh is gg+40
 * gg xx xx xx where gg is c0-de	hh xx xx xx + 202020 where hh is gg-c0
 * gg xx xx xx where gg is e1-ff	gg xx xx xx - 20201f
 * gg xx xx xx xx where gg is df-e0	xx xx xx xx
 * Numbers encoded in five bytes mean elevations higher than 8224 m, which is
 * higher than anything in a geoid file, but can occur in a DEM of a tall
 * mountain or deep trench.
 */
{
  char buf[8];
  if (i==0x80000000)
  {
    buf[0]=0x20;
    file.write(buf,1);
  }
  else if (i>=0 && i<0x20)
  {
    *(int *)buf=i;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+3,1);
  }
  else if (i<0 && i>-0x20)
  {
    *(int *)buf=i-0xc0;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+3,1);
  }
  else if (i>=0 && i<0x2020)
  {
    *(int *)buf=i-0x20+0x4000;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+2,2);
  }
  else if (i<0 && i>-0x2020)
  {
    *(int *)buf=i+0x20+0x7fff;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+2,2);
  }
  else if (i>=0 && i<0x202020)
  {
    *(int *)buf=i-0x2020+0x800000;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+1,3);
  }
  else if (i<0 && i>-0x202020)
  {
    *(int *)buf=i+0x2020+0xbfffff;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf+1,3);
  }
  else if (i>=0 && i<0x1f202020)
  {
    *(int *)buf=i-0x202020+0xc0000000;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf,4);
  }
  else if (i<0 && i>-0x1f202020)
  {
    *(int *)buf=i+0x202020+0xffffffff;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    file.write(buf,4);
  }
  else
  {
    *(int *)buf=i;
#ifndef BIGENDIAN
    endianflip(buf,4);
#endif
    memmove(buf+1,buf,4);
    buf[0]=(i<0)?0xdf:0xe0;
    file.write(buf,5);
  }
}

int readgeint(std::istream &file)
{
  char buf[8];
  int ret,nbytes,i;
  file.read(buf,1);
  nbytes=((buf[0]>>6)&3)+1;
  file.read(buf+1,nbytes-1);
  if ((buf[0]&0xff)==0xdf || (buf[0]&0xff)==0xe0)
  {
    file.read(buf+4,1);
    nbytes++;
  }
  if (nbytes<4)
    memmove(buf+4-nbytes,buf,nbytes);
  if (nbytes>4)
    memmove(buf,buf+1,4);
  if (nbytes<5)
  {
    ret=(buf[4-nbytes]&32)/-32;
    buf[4-nbytes]=(buf[4-nbytes]&63)|(ret&0xc0);
    for (i=0;i<4-nbytes;i++)
      buf[i]=ret;
  }
#ifndef BIGENDIAN
  endianflip(buf,4);
#endif
  ret=*(int *)buf;
  switch (nbytes)
  {
    case 1: // ffffffe0-0000001f: ffffffe0 means 80000000, rest stay same
      if (ret==-32)
        ret=0x80000000;
      break;
    case 2: // ffffe000-ffffffdf, 00000020-00001fff
      if (ret<0)
        ret-=0x1f;
      else
        ret+=0x20;
      break;
    case 3: // ffe00000-ffffdfff, 00002000-001fffff
      if (ret<0)
        ret-=0x201f;
      else
        ret+=0x2020;
      break;
    case 4: // e1000000-ffdfffff, 00200000-1effffff
      if (ret<0)
        ret-=0x20201f;
      else
        ret+=0x202020;
      break;
  }
  return ret;
}

void writeustring(ostream &file,string s)
// FIXME: if s contains a null character, it should be written as c0 a0
{
  file.write(s.data(),s.length());
  file.put(0);
}

string readustring(istream &file)
{
  int ch;
  string ret;
  do
  {
    ch=file.get();
    if (ch>0)
      ret+=(char)ch;
  } while (ch>0);
  return ret;
}