panthema / 2006 / SDIOS06 / sdios06 / src / supertux / lispreader.cpp (Download File)
/* $Id: lispreader.cpp 2273 2005-01-08 12:40:47Z rmcruz $ */
/*
 * lispreader.c
 *
 * Copyright (C) 1998-2000 Mark Probst
 * Copyright (C) 2002 Ingo Ruhnke <grumbel@gmx.de>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <iostream>
#include <string>
#include <assert.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "setup.h"
#include "lispreader.h"

#define TOKEN_ERROR                   -1
#define TOKEN_EOF                     0
#define TOKEN_OPEN_PAREN              1
#define TOKEN_CLOSE_PAREN             2
#define TOKEN_SYMBOL                  3
#define TOKEN_STRING                  4
#define TOKEN_INTEGER                 5
#define TOKEN_REAL                    6
#define TOKEN_PATTERN_OPEN_PAREN      7
#define TOKEN_DOT                     8
#define TOKEN_TRUE                    9
#define TOKEN_FALSE                   10


#define MAX_TOKEN_LENGTH           1024

static char token_string[MAX_TOKEN_LENGTH + 1] = "";
static int token_length = 0;

static lisp_object_t end_marker = { LISP_TYPE_EOF, {{0, 0}} };
static lisp_object_t error_object = { LISP_TYPE_PARSE_ERROR , {{0,0}}  };
static lisp_object_t close_paren_marker = { LISP_TYPE_PARSE_ERROR , {{0,0}}  };
static lisp_object_t dot_marker = { LISP_TYPE_PARSE_ERROR , {{0,0}} };

static void
_token_clear (void)
{
  token_string[0] = '\0';
  token_length = 0;
}

static void
_token_append (char c)
{
  assert(token_length < MAX_TOKEN_LENGTH);

  token_string[token_length++] = c;
  token_string[token_length] = '\0';
}

static int
_next_char (lisp_stream_t *stream)
{
  switch (stream->type)
    {
    case LISP_STREAM_FILE :
      return getc(stream->v.file);

    case LISP_STREAM_STRING :
      {
        char c = stream->v.string.buf[stream->v.string.pos];

        if (c == 0)
          return EOF;

        ++stream->v.string.pos;

        return c;
      }

    case LISP_STREAM_ANY:
      return stream->v.any.next_char(stream->v.any.data);
    }
  assert(0);
  return EOF;
}

static void
_unget_char (char c, lisp_stream_t *stream)
{
  switch (stream->type)
    {
    case LISP_STREAM_FILE :
      ungetc(c, stream->v.file);
      break;

    case LISP_STREAM_STRING :
      --stream->v.string.pos;
      break;

    case LISP_STREAM_ANY:
      stream->v.any.unget_char(c, stream->v.any.data);
      break;

    default :
      assert(0);
    }
}

static int
_scan (lisp_stream_t *stream)
{
  static char *delims = "\"();";

  int c;

  _token_clear();

  do
    {
      c = _next_char(stream);
      if (c == EOF)
        return TOKEN_EOF;
      else if (c == ';')     	 /* comment start */
        while (1)
          {
            c = _next_char(stream);
            if (c == EOF)
              return TOKEN_EOF;
            else if (c == '\n')
              break;
          }
    }
  while (isspace(c));

  switch (c)
    {
    case '(' :
      return TOKEN_OPEN_PAREN;

    case ')' :
      return TOKEN_CLOSE_PAREN;

    case '"' :
      while (1)
        {
          c = _next_char(stream);
          if (c == EOF)
            return TOKEN_ERROR;
          if (c == '"')
            break;
          if (c == '\\')
            {
              c = _next_char(stream);

              switch (c)
                {
                case EOF :
                  return TOKEN_ERROR;

                case 'n' :
                  c = '\n';
                  break;

                case 't' :
                  c = '\t';
                  break;
                }
            }

          _token_append(c);
        }
      return TOKEN_STRING;

    case '#' :
      c = _next_char(stream);
      if (c == EOF)
        return TOKEN_ERROR;

      switch (c)
        {
        case 't' :
          return TOKEN_TRUE;

        case 'f' :
          return TOKEN_FALSE;

        case '?' :
          c = _next_char(stream);
          if (c == EOF)
            return TOKEN_ERROR;

          if (c == '(')
            return TOKEN_PATTERN_OPEN_PAREN;
          else
            return TOKEN_ERROR;
        }
      return TOKEN_ERROR;

    default :
      if (isdigit(c) || c == '-')
        {
          int have_nondigits = 0;
          int have_digits = 0;
          int have_floating_point = 0;

          do
            {
              if (isdigit(c))
                have_digits = 1;
              else if (c == '.')
                have_floating_point++;
              _token_append(c);

              c = _next_char(stream);

              if (c != EOF && !isdigit(c) && !isspace(c) && c != '.' && !strchr(delims, c))
                have_nondigits = 1;
            }
          while (c != EOF && !isspace(c) && !strchr(delims, c));

          if (c != EOF)
            _unget_char(c, stream);

          if (have_nondigits || !have_digits || have_floating_point > 1)
            return TOKEN_SYMBOL;
          else if (have_floating_point == 1)
            return TOKEN_REAL;
          else
            return TOKEN_INTEGER;
        }
      else
        {
          if (c == '.')
            {
              c = _next_char(stream);
              if (c != EOF && !isspace(c) && !strchr(delims, c))
                _token_append('.');
              else
                {
                  _unget_char(c, stream);
                  return TOKEN_DOT;
                }
            }
          do
            {
              _token_append(c);
              c = _next_char(stream);
            }
          while (c != EOF && !isspace(c) && !strchr(delims, c));
          if (c != EOF)
            _unget_char(c, stream);

          return TOKEN_SYMBOL;
        }
    }

  assert(0);
  return TOKEN_ERROR;
}

static lisp_object_t*
lisp_object_alloc (int type)
{
  lisp_object_t *obj = (lisp_object_t*)malloc(sizeof(lisp_object_t));

  obj->type = type;

  return obj;
}

lisp_stream_t*
lisp_stream_init_file (lisp_stream_t *stream, FILE *file)
{
  stream->type = LISP_STREAM_FILE;
  stream->v.file = file;

  return stream;
}

lisp_stream_t*
lisp_stream_init_string (lisp_stream_t *stream, char *buf)
{
  stream->type = LISP_STREAM_STRING;
  stream->v.string.buf = buf;
  stream->v.string.pos = 0;

  return stream;
}

lisp_stream_t*
lisp_stream_init_any (lisp_stream_t *stream, void *data,
                      int (*next_char) (void *data),
                      void (*unget_char) (char c, void *data))
{
  assert(next_char != 0 && unget_char != 0);

  stream->type = LISP_STREAM_ANY;
  stream->v.any.data = data;
  stream->v.any.next_char= next_char;
  stream->v.any.unget_char = unget_char;

  return stream;
}

lisp_object_t*
lisp_make_integer (int value)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_INTEGER);

  obj->v.integer = value;

  return obj;
}

lisp_object_t*
lisp_make_real (float value)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_REAL);

  obj->v.real = value;

  return obj;
}

lisp_object_t*
lisp_make_symbol (const char *value)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_SYMBOL);

  obj->v.string = strdup(value);

  return obj;
}

lisp_object_t*
lisp_make_string (const char *value)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_STRING);

  obj->v.string = strdup(value);

  return obj;
}

lisp_object_t*
lisp_make_cons (lisp_object_t *car, lisp_object_t *cdr)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_CONS);

  obj->v.cons.car = car;
  obj->v.cons.cdr = cdr;

  return obj;
}

lisp_object_t*
lisp_make_boolean (int value)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_BOOLEAN);

  obj->v.integer = value ? 1 : 0;

  return obj;
}

static lisp_object_t*
lisp_make_pattern_cons (lisp_object_t *car, lisp_object_t *cdr)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_PATTERN_CONS);

  obj->v.cons.car = car;
  obj->v.cons.cdr = cdr;

  return obj;
}

static lisp_object_t*
lisp_make_pattern_var (int type, int index, lisp_object_t *sub)
{
  lisp_object_t *obj = lisp_object_alloc(LISP_TYPE_PATTERN_VAR);

  obj->v.pattern.type = type;
  obj->v.pattern.index = index;
  obj->v.pattern.sub = sub;

  return obj;
}

lisp_object_t*
lisp_read (lisp_stream_t *in)
{
  int token = _scan(in);
  lisp_object_t *obj = lisp_nil();

  if (token == TOKEN_EOF)
    return &end_marker;

  switch (token)
    {
    case TOKEN_ERROR :
      return &error_object;

    case TOKEN_EOF :
      return &end_marker;

    case TOKEN_OPEN_PAREN :
    case TOKEN_PATTERN_OPEN_PAREN :
      {
        lisp_object_t *last = lisp_nil(), *car;

        do
          {
            car = lisp_read(in);
            if (car == &error_object || car == &end_marker)
              {
                lisp_free(obj);
                return &error_object;
              }
            else if (car == &dot_marker)
              {
                if (lisp_nil_p(last))
                  {
                    lisp_free(obj);
                    return &error_object;
                  }

                car = lisp_read(in);
                if (car == &error_object || car == &end_marker)
                  {
                    lisp_free(obj);
                    return car;
                  }
                else
                  {
                    last->v.cons.cdr = car;

                    if (_scan(in) != TOKEN_CLOSE_PAREN)
                      {
                        lisp_free(obj);
                        return &error_object;
                      }

                    car = &close_paren_marker;
                  }
              }
            else if (car != &close_paren_marker)
              {
                if (lisp_nil_p(last))
                  obj = last = (token == TOKEN_OPEN_PAREN ? lisp_make_cons(car, lisp_nil()) : lisp_make_pattern_cons(car, lisp_nil()));
                else
                  last = last->v.cons.cdr = lisp_make_cons(car, lisp_nil());
              }
          }
        while (car != &close_paren_marker);
      }
      return obj;

    case TOKEN_CLOSE_PAREN :
      return &close_paren_marker;

    case TOKEN_SYMBOL :
      return lisp_make_symbol(token_string);

    case TOKEN_STRING :
      return lisp_make_string(token_string);

    case TOKEN_INTEGER :
      return lisp_make_integer(atoi(token_string));

    case TOKEN_REAL :
      return lisp_make_real((float)atof(token_string));

    case TOKEN_DOT :
      return &dot_marker;

    case TOKEN_TRUE :
      return lisp_make_boolean(1);

    case TOKEN_FALSE :
      return lisp_make_boolean(0);
    }

  assert(0);
  return &error_object;
}

void
lisp_free (lisp_object_t *obj)
{
  /** This goto solution has to be done cause using a recursion
      may cause a stack overflaw (for instance, in MacOS 10.2). */

 restart:

  if (obj == 0)
    return;

  switch (obj->type)
    {
    case LISP_TYPE_INTERNAL :
    case LISP_TYPE_PARSE_ERROR :
    case LISP_TYPE_EOF :
      return;

    case LISP_TYPE_SYMBOL :
    case LISP_TYPE_STRING :
      free(obj->v.string);
      break;

    case LISP_TYPE_CONS :
    case LISP_TYPE_PATTERN_CONS :
      /* If we just recursively free car and cdr we risk a stack
         overflow because lists may be nested arbitrarily deep.

         We can get rid of one recursive call with a tail call,
         but there's still one remaining.

         The solution is to flatten a recursive list until we
         can free the car without recursion.  Then we free the
         cdr with a tail call.

         The transformation we perform on the list is this:

           ((a . b) . c) -> (a . (b . c))
      */
      if (!lisp_nil_p(obj->v.cons.car)
        && (lisp_type(obj->v.cons.car) == LISP_TYPE_CONS
        || lisp_type(obj->v.cons.car) == LISP_TYPE_PATTERN_CONS))
        {
        /* this is the transformation */

        lisp_object_t *car, *cdar;

        car = obj->v.cons.car;
        cdar = car->v.cons.cdr;

        car->v.cons.cdr = obj;

        obj->v.cons.car = cdar;

        obj = car;

        goto restart;
        }
      else
        {
        /* here we just free the car (which is not recursive),
           the cons itself and the cdr via a tail call.  */

        lisp_object_t *tmp;

        lisp_free(obj->v.cons.car);

        tmp = obj;
        obj = obj->v.cons.cdr;

        free(tmp);

        goto restart;
        }

    case LISP_TYPE_PATTERN_VAR :
      lisp_free(obj->v.pattern.sub);
      break;
    }

  free(obj);
}

lisp_object_t*
lisp_read_from_string (const char *buf)
{
  lisp_stream_t stream;

  lisp_stream_init_string(&stream, (char*)buf);
  return lisp_read(&stream);
}

static int
_compile_pattern (lisp_object_t **obj, int *index)
{
  if (*obj == 0)
    return 1;

  switch (lisp_type(*obj))
    {
    case LISP_TYPE_PATTERN_CONS :
      {
        struct
          {
            char *name;
            int type;
          }
        types[] =
          {
            { "any", LISP_PATTERN_ANY },
            { "symbol", LISP_PATTERN_SYMBOL },
            { "string", LISP_PATTERN_STRING },
            { "integer", LISP_PATTERN_INTEGER },
            { "real", LISP_PATTERN_REAL },
            { "boolean", LISP_PATTERN_BOOLEAN },
            { "list", LISP_PATTERN_LIST },
            { "or", LISP_PATTERN_OR },
            { 0, 0 }
          };
        char *type_name;
        int type;
        int i;
        lisp_object_t *pattern;
        type = -1;
	
        if (lisp_type(lisp_car(*obj)) != LISP_TYPE_SYMBOL)
          return 0;

        type_name = lisp_symbol(lisp_car(*obj));
        for (i = 0; types[i].name != 0; ++i)
          {
            if (strcmp(types[i].name, type_name) == 0)
              {
                type = types[i].type;
                break;
              }
          }

        if (types[i].name == 0)
          return 0;

        if (type != LISP_PATTERN_OR && lisp_cdr(*obj) != 0)
          return 0;

        pattern = lisp_make_pattern_var(type, (*index)++, lisp_nil());

        if (type == LISP_PATTERN_OR)
          {
            lisp_object_t *cdr = lisp_cdr(*obj);

            if (!_compile_pattern(&cdr, index))
              {
                lisp_free(pattern);
                return 0;
              }

            pattern->v.pattern.sub = cdr;

            (*obj)->v.cons.cdr = lisp_nil();
          }

        lisp_free(*obj);

        *obj = pattern;
      }
      break;

    case LISP_TYPE_CONS :
      if (!_compile_pattern(&(*obj)->v.cons.car, index))
        return 0;
      if (!_compile_pattern(&(*obj)->v.cons.cdr, index))
        return 0;
      break;
    }

  return 1;
}

int
lisp_compile_pattern (lisp_object_t **obj, int *num_subs)
{
  int index = 0;
  int result;

  result = _compile_pattern(obj, &index);

  if (result && num_subs != 0)
    *num_subs = index;

  return result;
}

static int _match_pattern (lisp_object_t *pattern, lisp_object_t *obj, lisp_object_t **vars);

static int
_match_pattern_var (lisp_object_t *pattern, lisp_object_t *obj, lisp_object_t **vars)
{
  assert(lisp_type(pattern) == LISP_TYPE_PATTERN_VAR);

  switch (pattern->v.pattern.type)
    {
    case LISP_PATTERN_ANY :
      break;

    case LISP_PATTERN_SYMBOL :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_SYMBOL)
        return 0;
      break;

    case LISP_PATTERN_STRING :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_STRING)
        return 0;
      break;

    case LISP_PATTERN_INTEGER :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_INTEGER)
        return 0;
      break;

    case LISP_PATTERN_REAL :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_REAL)
        return 0;
      break;

    case LISP_PATTERN_BOOLEAN :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_BOOLEAN)
        return 0;
      break;

    case LISP_PATTERN_LIST :
      if (obj == 0 || lisp_type(obj) != LISP_TYPE_CONS)
        return 0;
      break;

    case LISP_PATTERN_OR :
      {
        lisp_object_t *sub;
        int matched = 0;

        for (sub = pattern->v.pattern.sub; sub != 0; sub = lisp_cdr(sub))
          {
            assert(lisp_type(sub) == LISP_TYPE_CONS);

            if (_match_pattern(lisp_car(sub), obj, vars))
              matched = 1;
          }

        if (!matched)
          return 0;
      }
      break;

    default :
      assert(0);
    }

  if (vars != 0)
    vars[pattern->v.pattern.index] = obj;

  return 1;
}

static int
_match_pattern (lisp_object_t *pattern, lisp_object_t *obj, lisp_object_t **vars)
{
  if (pattern == 0)
    return obj == 0;

  if (obj == 0)
    return 0;

  if (lisp_type(pattern) == LISP_TYPE_PATTERN_VAR)
    return _match_pattern_var(pattern, obj, vars);

  if (lisp_type(pattern) != lisp_type(obj))
    return 0;

  switch (lisp_type(pattern))
    {
    case LISP_TYPE_SYMBOL :
      return strcmp(lisp_symbol(pattern), lisp_symbol(obj)) == 0;

    case LISP_TYPE_STRING :
      return strcmp(lisp_string(pattern), lisp_string(obj)) == 0;

    case LISP_TYPE_INTEGER :
      return lisp_integer(pattern) == lisp_integer(obj);

    case LISP_TYPE_REAL :
      return lisp_real(pattern) == lisp_real(obj);

    case LISP_TYPE_CONS :
      {
        int result1, result2;

        result1 = _match_pattern(lisp_car(pattern), lisp_car(obj), vars);
        result2 = _match_pattern(lisp_cdr(pattern), lisp_cdr(obj), vars);

        return result1 && result2;
      }
      break;

    default :
      assert(0);
    }

  return 0;
}

int
lisp_match_pattern (lisp_object_t *pattern, lisp_object_t *obj, lisp_object_t **vars, int num_subs)
{
  int i;

  if (vars != 0)
    for (i = 0; i < num_subs; ++i)
      vars[i] = &error_object;

  return _match_pattern(pattern, obj, vars);
}

int
lisp_match_string (const char *pattern_string, lisp_object_t *obj, lisp_object_t **vars)
{
  lisp_object_t *pattern;
  int result;
  int num_subs;

  pattern = lisp_read_from_string(pattern_string);

  if (pattern != 0 && (lisp_type(pattern) == LISP_TYPE_EOF
                       || lisp_type(pattern) == LISP_TYPE_PARSE_ERROR))
    return 0;

  if (!lisp_compile_pattern(&pattern, &num_subs))
    {
      lisp_free(pattern);
      return 0;
    }

  result = lisp_match_pattern(pattern, obj, vars, num_subs);

  lisp_free(pattern);

  return result;
}

int
lisp_type (lisp_object_t *obj)
{
  if (obj == 0)
    return LISP_TYPE_NIL;
  return obj->type;
}

int
lisp_integer (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_INTEGER);

  return obj->v.integer;
}

char*
lisp_symbol (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_SYMBOL);

  return obj->v.string;
}

char*
lisp_string (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_STRING);

  return obj->v.string;
}

int
lisp_boolean (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_BOOLEAN);

  return obj->v.integer;
}

float
lisp_real (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_REAL || obj->type == LISP_TYPE_INTEGER);

  if (obj->type == LISP_TYPE_INTEGER)
    return obj->v.integer;
  return obj->v.real;
}

lisp_object_t*
lisp_car (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_CONS || obj->type == LISP_TYPE_PATTERN_CONS);

  return obj->v.cons.car;
}

lisp_object_t*
lisp_cdr (lisp_object_t *obj)
{
  assert(obj->type == LISP_TYPE_CONS || obj->type == LISP_TYPE_PATTERN_CONS);

  return obj->v.cons.cdr;
}

lisp_object_t*
lisp_cxr (lisp_object_t *obj, const char *x)
{
  int i;

  for (i = strlen(x) - 1; i >= 0; --i)
    if (x[i] == 'a')
      obj = lisp_car(obj);
    else if (x[i] == 'd')
      obj = lisp_cdr(obj);
    else
      assert(0);

  return obj;
}

int
lisp_list_length (lisp_object_t *obj)
{
  int length = 0;

  while (obj != 0)
    {
      assert(obj->type == LISP_TYPE_CONS || obj->type == LISP_TYPE_PATTERN_CONS);

      ++length;
      obj = obj->v.cons.cdr;
    }

  return length;
}

lisp_object_t*
lisp_list_nth_cdr (lisp_object_t *obj, int index)
{
  while (index > 0)
    {
      assert(obj != 0);
      assert(obj->type == LISP_TYPE_CONS || obj->type == LISP_TYPE_PATTERN_CONS);

      --index;
      obj = obj->v.cons.cdr;
    }

  return obj;
}

lisp_object_t*
lisp_list_nth (lisp_object_t *obj, int index)
{
  obj = lisp_list_nth_cdr(obj, index);

  assert(obj != 0);

  return obj->v.cons.car;
}

void
lisp_dump (lisp_object_t *obj, FILE *out)
{
  if (obj == 0)
    {
      fprintf(out, "()");
      return;
    }

  switch (lisp_type(obj))
    {
    case LISP_TYPE_EOF :
      fputs("#<eof>", out);
      break;

    case LISP_TYPE_PARSE_ERROR :
      fputs("#<error>", out);
      break;

    case LISP_TYPE_INTEGER :
      fprintf(out, "%d", lisp_integer(obj));
      break;

    case LISP_TYPE_REAL :
      fprintf(out, "%f", lisp_real(obj));
      break;

    case LISP_TYPE_SYMBOL :
      fputs(lisp_symbol(obj), out);
      break;

    case LISP_TYPE_STRING :
      {
        char *p;

        fputc('"', out);
        for (p = lisp_string(obj); *p != 0; ++p)
          {
            if (*p == '"' || *p == '\\')
              fputc('\\', out);
            fputc(*p, out);
          }
        fputc('"', out);
      }
      break;

    case LISP_TYPE_CONS :
    case LISP_TYPE_PATTERN_CONS :
      fputs(lisp_type(obj) == LISP_TYPE_CONS ? "(" : "#?(", out);
      while (obj != 0)
        {
          lisp_dump(lisp_car(obj), out);
          obj = lisp_cdr(obj);
          if (obj != 0)
            {
              if (lisp_type(obj) != LISP_TYPE_CONS
                  && lisp_type(obj) != LISP_TYPE_PATTERN_CONS)
                {
                  fputs(" . ", out);
                  lisp_dump(obj, out);
                  break;
                }
              else
                fputc(' ', out);
            }
        }
      fputc(')', out);
      break;

    case LISP_TYPE_BOOLEAN :
      if (lisp_boolean(obj))
        fputs("#t", out);
      else
        fputs("#f", out);
      break;

    default :
      assert(0);
    }
}

using namespace std;

LispReader::LispReader (lisp_object_t* l)
    : lst (l)
{
  //std::cout << "LispReader: " << std::flush;
  //lisp_dump(lst, stdout);
  //std::cout << std::endl;
}

lisp_object_t*
LispReader::search_for(const char* name)
{
  //std::cout << "LispReader::search_for(" << name << ")" << std::endl;
  lisp_object_t* cursor = lst;

  while(!lisp_nil_p(cursor))
    {
      lisp_object_t* cur = lisp_car(cursor);

      if (!lisp_cons_p(cur) || !lisp_symbol_p (lisp_car(cur)))
        {
          lisp_dump(cur, stdout);
          //throw ConstruoError (std::string("LispReader: Read error in search_for ") + name);
	  printf("LispReader: Read error in search\n");
        }
      else
        {
          if (strcmp(lisp_symbol(lisp_car(cur)), name) == 0)
            {
              return lisp_cdr(cur);
            }
        }

      cursor = lisp_cdr (cursor);
    }
  return 0;
}

bool
LispReader::read_int (const char* name, int* i)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      if (!lisp_integer_p(lisp_car(obj)))
      {
        //st_abort("LispReader expected type integer at token: ", name); /* Instead of giving up, we return with false now. */
	return false;
	}
      *i = lisp_integer(lisp_car(obj));
      return true;
    }
  return false;
}

bool
LispReader::read_lisp(const char* name, lisp_object_t** b)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      *b = obj;
      return true;
    }
  else
    return false;
}

bool
LispReader::read_float (const char* name, float* f)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      if (!lisp_real_p(lisp_car(obj)) && !lisp_integer_p(lisp_car(obj)))
        st_abort("LispReader expected type real at token: ", name);
      *f = lisp_real(lisp_car(obj));
      return true;
    }
  return false;
}

bool
LispReader::read_string_vector (const char* name, std::vector<std::string>* vec)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      while(!lisp_nil_p(obj))
        {
          if (!lisp_string_p(lisp_car(obj)))
            st_abort("LispReader expected type string at token: ", name);
          vec->push_back(lisp_string(lisp_car(obj)));
          obj = lisp_cdr(obj);
        }
      return true;
    }
  return false;    
}

bool
LispReader::read_int_vector (const char* name, std::vector<int>* vec)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      while(!lisp_nil_p(obj))
        {
          if (!lisp_integer_p(lisp_car(obj)))
            st_abort("LispReader expected type integer at token: ", name);
          vec->push_back(lisp_integer(lisp_car(obj)));
          obj = lisp_cdr(obj);
        }
      return true;
    }
  return false;    
}

bool
LispReader::read_char_vector (const char* name, std::vector<char>* vec)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      while(!lisp_nil_p(obj))
        {
          vec->push_back(*lisp_string(lisp_car(obj)));
          obj = lisp_cdr(obj);
        }
      return true;
    }
  return false;    
}

bool
LispReader::read_string (const char* name, std::string* str)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      if (!lisp_string_p(lisp_car(obj)))
        st_abort("LispReader expected type string at token: ", name);
     *str = lisp_string(lisp_car(obj));
      return true;
    }
  return false;  
}

bool
LispReader::read_bool (const char* name, bool* b)
{
  lisp_object_t* obj = search_for (name);
  if (obj)
    {
      if (!lisp_boolean_p(lisp_car(obj)))
        st_abort("LispReader expected type bool at token: ", name);
      *b = lisp_boolean(lisp_car(obj));
      return true;
    }
  return false;
}

LispWriter::LispWriter (const char* name)
{
  lisp_objs.push_back(lisp_make_symbol (name));
}

void
LispWriter::append (lisp_object_t* obj)
{
  lisp_objs.push_back(obj);
}

lisp_object_t*
LispWriter::make_list3 (lisp_object_t* a, lisp_object_t* b, lisp_object_t* c)
{
  return lisp_make_cons (a, lisp_make_cons(b, lisp_make_cons(c, lisp_nil())));
}

lisp_object_t*
LispWriter::make_list2 (lisp_object_t* a, lisp_object_t* b)
{
  return lisp_make_cons (a, lisp_make_cons(b, lisp_nil()));
}

void
LispWriter::write_float (const char* name, float f)
{
  append(make_list2 (lisp_make_symbol (name),
                     lisp_make_real(f)));
}

void
LispWriter::write_int (const char* name, int i)
{
  append(make_list2 (lisp_make_symbol (name),
                     lisp_make_integer(i)));
}

void
LispWriter::write_string (const char* name, const char* str)
{
  append(make_list2 (lisp_make_symbol (name),
                     lisp_make_string(str)));
}

void
LispWriter::write_symbol (const char* name, const char* symname)
{
  append(make_list2 (lisp_make_symbol (name),
                     lisp_make_symbol(symname)));
}

void
LispWriter::write_lisp_obj(const char* name, lisp_object_t* lst)
{
  append(make_list2 (lisp_make_symbol (name),
                     lst));
}

void
LispWriter::write_boolean (const char* name, bool b)
{
  append(make_list2 (lisp_make_symbol (name),
                     lisp_make_boolean(b)));
}

lisp_object_t*
LispWriter::create_lisp ()
{
  lisp_object_t* lisp_obj = lisp_nil();

  for(std::vector<lisp_object_t*>::reverse_iterator i = lisp_objs.rbegin ();
      i != lisp_objs.rend (); ++i)
    {
      lisp_obj = lisp_make_cons (*i, lisp_obj);
    }
  lisp_objs.clear();

  return lisp_obj;
}

#if 0
void mygzungetc(char c, void* file)
{
  gzungetc(c, file);
}

lisp_stream_t* lisp_stream_init_gzfile (lisp_stream_t *stream, gzFile file)
{
  return lisp_stream_init_any (stream, file, gzgetc, mygzungetc);
}
#endif

lisp_object_t* lisp_read_from_gzfile(const char* filename)
{
  bool done = false;
  lisp_object_t* root_obj = 0;
  int chunk_size = 128 * 1024;
  int buf_pos = 0;
  int try_number = 1;
  char* buf = static_cast<char*>(malloc(chunk_size));
  assert(buf);

  gzFile in = gzopen(filename, "r");

  while (!done)
    {
      int ret = gzread(in, buf + buf_pos, chunk_size);
      if (ret == -1)
        {
          free (buf);
          assert(!"Error while reading from file");
        }
      else if (ret == chunk_size) // buffer got full, eof not yet there so resize
        {
          buf_pos = chunk_size * try_number;
          try_number += 1;
          buf = static_cast<char*>(realloc(buf, chunk_size * try_number));
          assert(buf);
        }
      else 
        {
          // everything fine, encountered EOF 
          done = true;
        }
    }
      
  lisp_stream_t stream;
  lisp_stream_init_string (&stream, buf);
  root_obj = lisp_read (&stream);
      
  free(buf);
  gzclose(in);

  return root_obj;
}

bool has_suffix(const char* data, const char* suffix)
{
  int suffix_len = strlen(suffix);
  int data_len   = strlen(data);
  
  const char* data_suffix = (data + data_len - suffix_len);

  if (data_suffix >= data)
    {
      return (strcmp(data_suffix, suffix) == 0);
    }
  else
    {
      return false;
    }
}

lisp_object_t* lisp_read_from_file(const std::string& filename)
{
  lisp_stream_t stream;

  if (has_suffix(filename.c_str(), ".gz"))
    {
      return lisp_read_from_gzfile(filename.c_str());
    }
  else
    {
      lisp_object_t* obj = 0;
      FILE* in = fopen(filename.c_str(), "r");

      if (in)
        {
          lisp_stream_init_file(&stream, in);
          obj = lisp_read(&stream);
          fclose(in);
        }

      return obj;
    }
}

// EOF //
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