/*
 * Copyright 2005-2015 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */


/*

  Author: B.Raoult
  Modified by Enrico Fucile

*/


#include "grib_api_internal.h"
#include <math.h>
#include <errno.h>
#include <signal.h>
#include <ctype.h>
#include <stdlib.h>

#if 0
GRIB_INLINE static int strcmp(const char* a,const char* b) {
  if (*a != *b) return 1;
  while((*a!=0 && *b!=0) &&  *(a) == *(b) ) {a++;b++;}
  return (*a==0 && *b==0) ? 0 : 1;
}
#endif

#define SIZE  ((int)4097)
#ifndef NUMBER
#define NUMBER(a)    (sizeof(a)/sizeof(a[0])) /* number of elem. of an array */
#endif
#ifndef MAX
#define MAX(a,b) (((a)>(b))?(a):(b))
#endif
#ifndef MIN
#define MIN(a,b) (((a)<(b))?(a):(b))
#endif
#define ABS(a)       ((a)<0?-(a):(a))
#define ROUND(a)     ((long)((a)+0.5))
#define EQ(a,b)      ((*(a) == *(b)) && (strcmp(a,b) == 0))
#define LT(a,b)      ((*(a) <  *(b)) || (strcmp(a,b) < 0))


static grib_math *readpower(grib_context* c,char** form,int *err);
static grib_math *readatom(grib_context* c,char** form,int *err);
static grib_math *readfactor(grib_context* c,char** form,int *err);
static grib_math *readterm(grib_context* c,char** form,int *err);
static grib_math *readtest(grib_context* c,char** form,int *err);
static grib_math *readlist(grib_context* c,char** form,int* n,int *err);
static grib_math *readand(grib_context* c,char** form,int* err);
static grib_math *reador(grib_context* c,char** form,int* err);
static void advance(char** form);
static char *opname(char *p,int n);
/*
static long op_eq(long a, long b)     {return a == b;}
static long op_ne(long a, long b)     {return a != b;}
static long op_lt(long a, long b)     {return a <  b;}
static long op_gt(long a, long b)     {return a >  b;}
static long op_and(long a, long b)    {return a && b;}
static long op_or(long a, long b)     {return a || b;}
static long op_ge(long a, long b)     {return a >= b;}
static long op_le(long a, long b)     {return a <= b;}

static long op_bit(long a, long b)    {return a&(1<<b);}
static long op_bitoff(long a, long b) {return !op_bit(a,b);}

static long op_not(long a) {return !a;}
static long op_neg(long a) {return -a;}

static double op_neg_d(double a) {return -a;}

static long op_pow(long a, long b) {return grib_power(a,b);}
static long op_add(long a, long b) {return a+b;}
static long op_sub(long a, long b) {return a-b;}
static long op_div(long a, long b) {return a/b;}
static long op_mul(long a, long b) {return a*b;}
static long op_modulo(long a, long b) {return a%b;}

static double op_mul_d(double a, double b) {return a*b;}
static double op_div_d(double a, double b) {return a/b;}
static double op_add_d(double a, double b) {return a+b;}
static double op_sub_d(double a, double b) {return a-b;}

static double op_eq_d(double a, double b)     {return a == b;}
static double op_ne_d(double a, double b)     {return a != b;}
static double op_lt_d(double a, double b)     {return a <  b;}
static double op_gt_d(double a, double b)     {return a >  b;}
static double op_ge_d(double a, double b)     {return a >= b;}
static double op_le_d(double a, double b)     {return a <= b;}

static int op_eq_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) == 0 ? 1 : 0;
  return 0;
}
static int op_ne_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) == 0 ? 0 : 1;
  return 0;
}
static int op_lt_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) < 0 ? 1 : 0;
  return 0;
}
static int op_gt_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) > 0 ? 1 : 0;
  return 0;
}
static int op_ge_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) >= 0 ? 1 : 0;
  return 0;
}
static int op_le_string(char* a,char* b) {
  if (a && b) return strcmp(a,b) <= 0 ? 1 : 0;
  return 0;
}
*/

typedef double real;
typedef int boolean;
typedef int err;
typedef real (*fop1)(real);
typedef real (*fop2)(real,real);


static void advance(char** form) {
  (*form)++;
  while(isspace(**form)) (*form)++;
}

static grib_math *readatom(grib_context* c,char** form,int *err) {
  grib_math *p;
  int i;
  char buf[1024];

  switch(**form)
  {
  case '(':
    advance(form);
    p = reador(c,form,err);
    if(**form != ')') {
      grib_context_log(c, GRIB_LOG_ERROR,"Formula: missing )");
      *err = GRIB_INTERNAL_ERROR;
    }
    advance(form);
    break;

  case '-':
    p        = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    p->arity = 1;
    p->name  = strdup("neg");
    advance(form);
    p->left  = readatom(c,form,err);
    break;

  case '!':
    p        = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    p->arity = 1;
    p->name  = strdup("neg");
    advance(form);
    p->left  = readatom(c,form,err);
    break;

  case '\0':
    grib_context_log(c, GRIB_LOG_ERROR,"Formula: syntax error");
    *err = GRIB_INTERNAL_ERROR;
    return NULL;
    /*NOTREACHED*/
    break;

  default:
    i = 0;

    if(**form == '\'' || **form == '"')
    {
      char c = *((*form)++);
      while(**form && **form != c)
        buf[i++] = *((*form)++);
        if(**form) (*form)++;
    } else
      while(isalpha(**form)||isdigit(**form)
            || **form =='.' || **form == '_')
                buf[i++] = *((*form)++);

    buf[i] = 0;
    if(isspace(**form)) advance(form);

    p = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    p->name  = strdup(buf);
    p->left=0;

    switch(**form)
    {
    case '(':
      advance(form);
      p->arity = 0;
      p->left = readlist(c,form,&p->arity,err);
      if(**form != ')')
      {
        grib_context_log(c, GRIB_LOG_ERROR,"Formula: missing )");
        *err = GRIB_INTERNAL_ERROR;
      }
      advance(form);
      break;

    case '[':
      advance(form);
      p->arity = 0;
      p->left = readlist(c,form,&p->arity,err);
      if(**form != ']') {
        grib_context_log(c, GRIB_LOG_ERROR,"Formula: missing ]");
        *err = GRIB_INTERNAL_ERROR;
      }
      p->arity = -p->arity;
      advance(form);
      break;

    default:
      p->arity = 0;
      break;
    }

    break;
  }

  return p;
}

static char *opname(char *p,int n)
{
  char buf[5];
  strncpy(buf,p,n);
  buf[n] = 0;
  return strdup(buf);
}

void print_math(grib_math *m)
{
  if(m)
  {
    putchar('(');
    print_math(m->left);
    printf("%s",m->name);
    print_math(m->right);
    putchar(')');
  }
}

static grib_math *readpower(grib_context* c,char** form,int *err)
{
  grib_math *p = readatom(c,form,err);


  while(**form == '^' || (**form == '*' && *(*form + 1) == '*') )
  {
    grib_math *q  = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    q->left  = p;
    q->arity = 2;

    if(**form == '*') { advance(form); **form = '^'; }

    q->name     = opname(*form,1);
    advance(form);
    q->right    = readatom(c,form,err);
    p = q;
  }
  return p;
}

static grib_math *readlist(grib_context* c,char** form,int *n,int * err)
{
  grib_math *p;

  if(**form == ')') return NULL;

  p  = readtest(c,form,err);
  *n = 1;

  while(**form == ',')  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));

    (*n)++;

    q->left  = p;

    advance(form);

    q->right    = readtest(c,form,err);

    p = q;
  }
  return p;
}

static grib_math *readfactor(grib_context* c,char** form,int* err) {
  grib_math *p = readpower(c,form,err);

  while(**form == '*' || **form == '/')  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));

    q->arity    = 2;
    q->left     = p;
    q->name     = opname(*form,1);

    advance(form);

    q->right    = readpower(c,form,err);

    p = q;
  }
  return p;
}

static grib_math *readterm(grib_context* c,char** form,int* err) {
  grib_math *p = readfactor(c,form,err);
  while(**form == '+' || **form == '-' )  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));

    q->arity    = 2;
    q->left     = p;
    q->name     = opname(*form,1);

    advance(form);

    q->right    = readfactor(c,form,err);

    p = q;

  }
  return p;
}

static grib_math *readtest(grib_context* c,char** form,int* err) {
  grib_math *p = readterm(c,form,err);
  while(**form == '<' || **form == '>' || **form == '=')  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    char *x = *form;
    int   n = 1;

    q->arity    = 2;
    q->left     = p;

    advance(form);
    if(**form == '=' || **form == '>') {
      n = 2;
      advance(form);
    }

    q->name = opname(x,n);

    q->right    = readterm(c,form,err);

    p = q;

  }
  return p;
}

static grib_math *readand(grib_context* c,char** form,int* err) {
  grib_math *p = readtest(c,form,err);
  while(**form == '&' )  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    char *x = *form;
    int   n = 1;

    q->arity    = 2;
    q->left     = p;

    advance(form);
    if(**form == '&') {
      n = 2;
      advance(form);
    }

    q->name = opname(x,n);

    q->right    = readtest(c,form,err);

    p = q;

  }
  return p;
}

static grib_math *reador(grib_context* c,char** form,int* err) {
  grib_math *p = readand(c,form,err);
  while(**form == '|' )  {
    grib_math *q = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    char *x = *form;
    int   n = 1;

    q->arity    = 2;
    q->left     = p;

    advance(form);
    if(**form == '|' ) {
      n = 2;
      advance(form);
    }

    q->name = opname(x,n);

    q->right    = readand(c,form,err);

    p = q;

  }
  return p;
}

grib_math *grib_math_clone(grib_context* c,grib_math *m) {
  grib_math *n = NULL;
  if(m)  {
    n = (grib_math*)grib_context_malloc(c,sizeof(grib_math));
    n->arity = m->arity;
    n->name  = strdup(m->name);
    n->left  = grib_math_clone(c,m->left);
    n->right = grib_math_clone(c,m->right);
  }
  return n;
}

void grib_math_delete (grib_context* c,grib_math* m) {
     grib_math *left=0,*right=0;
     left=m->left;
     right=m->right;
     if (m->name) free(m->name);
     grib_context_free(c,m);
     if (left) grib_math_delete(c,left);
     if (right) grib_math_delete(c,right);
}

grib_math *grib_math_new(grib_context* c,const char* formula,int *err) {
  grib_math *x;
  char* f=0;
  char* fsave=0;

  *err=0;

  if (!formula) {*err=GRIB_INVALID_ARGUMENT;return NULL;}

  f=strdup(formula);
  fsave=f;

  x = reador(c,&f,err);
  if(*err!=GRIB_SUCCESS) return NULL;

  if(*f) {
    grib_context_log(c, GRIB_LOG_ERROR,
          "grib_math_new : Part of the formula was not processed: '%s'",f);
    return NULL;
  }

  free(fsave);

  return x;
}

