// Copyright status: this file is in the public domain.

#include <regex.h>
#include <stdlib.h>
#include <strings.h>

#include "lx.h"

static regex_t greg;
static int greg_set = 0;

static int geom_size(const char *spec, regmatch_t *rm, int min, int max, int *vp, LX_GEOMETRY *g, unsigned int bit)
{
 long int v;

 if (rm->rm_so < 0) return(0);
 if ((rm->rm_eo - rm->rm_so == 1) && (spec[rm->rm_so] == '.')) return(0);
 v = strtol(spec+rm->rm_so,0,10);
 if ((v < min) || (v > max)) return(1);
 *vp = v;
 g->flags |= bit;
 return(0);
}

static int geom_pos(const char *spec, regmatch_t *rm, int min, int max, int *vp, LX_GEOMETRY *g, unsigned int pbit, unsigned int nbit)
{
 long int v;

 if (rm->rm_so < 0) return(0);
 if ((rm->rm_eo - rm->rm_so == 1) && (spec[rm->rm_so] == '.')) return(0);
 v = strtol(spec+rm->rm_so,0,10);
 if ((v < min) || (v > max)) return(1.);
 *vp = v;
 g->flags |= (spec[rm->rm_so-1] == '+') ? pbit : nbit;
 return(0);
}

int lx_parse_geometry(const char *spec, LX_GEOMETRY *gp)
{
 int e;
 regmatch_t rm[7];

 gp->flags = 0;
 if (!spec || !*spec) return(0);
 if (! greg_set)
  { e = regcomp(&greg,"^(([0-9]+|\\.)x([0-9]+|\\.))?([-+](-?[0-9]+|\\.)[-+](-?[0-9]+|\\.))?$",REG_EXTENDED|REG_ICASE);
    if (e) abort();
    greg_set = 1;
  }
 e = regexec(&greg,spec,7,&rm[0],0);
 switch (e)
  { case 0:
       break;
    case REG_NOMATCH:
       return(LX_GEOM_ERR_SYNTAX);
       break;
    default:
       abort();
       break;
  }
 // 1: WxH (not useful)
 // 2: width
 // 3: height
 // 4: [-+]X[-+]Y (not useful)
 // 5: X
 // 6: Y
 if ( geom_size(spec,&rm[2],0,65535,&gp->w,gp,LX_GEOM_W) ||
      geom_size(spec,&rm[3],0,65535,&gp->h,gp,LX_GEOM_H) ||
      geom_pos(spec,&rm[5],-32767,32768,&gp->x,gp,LX_GEOM_PX,LX_GEOM_NX) ||
      geom_pos(spec,&rm[6],-32767,32768,&gp->y,gp,LX_GEOM_PY,LX_GEOM_NX) ) return(LX_GEOM_ERR_RANGE);
 return(0);
}