source: abuse/trunk/src/lcache.cpp @ 492 Tweet

/*
 *  Abuse - dark 2D side-scrolling platform game
 *  Copyright (c) 1995 Crack dot Com
 *
 *  This software was released into the Public Domain. As with most public
 *  domain software, no warranty is made or implied by Crack dot Com or
 *  Jonathan Clark.
 */

#include "config.h"

#include "lisp.h"
#include "specs.h"
#include "bus_type.h"

long block_size(Cell *level)  // return size needed to recreate this block
{
  int ret;
  if (!level) ret=0;    // NULL pointers don't need to be stored
  else
  {
    int type=item_type(level);
    if (type==L_CONS_CELL)
    {
    long t=0;
    void *b=level;
    for (;b && item_type(b)==L_CONS_CELL;b=CDR(b))
    {
      t+=sizeof(LList);
    }
    if (b) t+=block_size(b);
    for (b=level;b && item_type(b)==L_CONS_CELL;b=CDR(b))
      t+=block_size(CAR(b));
    ret=t;
    } else if (type== L_NUMBER)
    { ret=sizeof(LNumber); }
    else if (type==L_CHARACTER)
    { ret=sizeof(LChar); }
    else if (type==L_STRING)
    {
      ret=sizeof(LString)+strlen(lstring_value(level))+1;
      if (ret<8)
        ret=8;
    }
    else if (type==L_POINTER)
    { ret=sizeof(LPointer); }
    else ret=0;
  }
#ifdef WORD_ALIGN
  return (ret+3)&(~3);
#else
  return ret;
#endif
}



void write_level(bFILE *fp, Cell *level)
{
  int type=item_type(level);
  fp->write_uint8(type);


  switch (type)
  {
    case L_NUMBER :
    { fp->write_uint32(lnumber_value(level)); } break;
    case L_CHARACTER :
    { fp->write_uint16(lcharacter_value(level)); } break;
    case L_STRING :
    { long l=strlen(lstring_value(level))+1;
      fp->write_uint32(l);
      fp->write(lstring_value(level),l);
    } break;
    case L_SYMBOL :
    { fp->write_uint32((long)level); } break;
    case L_CONS_CELL :
    {
      if (!level) fp->write_uint32(0);
      else
      {
    long t=0;
    void *b=level;
    for (;b && item_type(b)==L_CONS_CELL;b=CDR(b)) t++;
    if (b)
    {
      fp->write_uint32(-t);      // negative number means dotted list
      write_level(fp,b);       // save end of dotted list
    }
    else fp->write_uint32(t);

    for (b=level;b && item_type(b)==L_CONS_CELL;b=CDR(b))
      write_level(fp,CAR(b));
      }
    } break;
  }
}

Cell *load_block(bFILE *fp)
{
  int type=fp->read_uint8();
  switch (type)
  {
    case L_NUMBER :
    { return LNumber::Create(fp->read_uint32()); } break;
    case L_CHARACTER :
    { return new_lisp_character(fp->read_uint16()); } break;
    case L_STRING :
    { long l=fp->read_uint32();
      LString *s = LString::Create(l);
      fp->read(lstring_value(s),l);
      return s;
    } break;
    case L_SYMBOL :
    { return (void *)fp->read_uint32(); } break;
    case L_CONS_CELL :
    {
      long t=fp->read_uint32();
      if (!t) return NULL;
      else
      {
    long x=abs(t);
    LList *last=NULL,*first=NULL;
    while (x)
    {
      LList *c = LList::Create();
      if (first)
        last->cdr=c;
      else first=c;
      last=c;
      x--;
    }
    last->cdr = (t < 0) ? (LObject *)load_block(fp) : NULL;

    for (last=first,x=0;x<abs(t);x++,last=(LList *)last->cdr)
      last->car = (LObject *)load_block(fp);
    return first;
      }
    }
  }
  return NULL;
}