#include <stdlib.h>

#include "stringgetter.h"

typedef enum {
	  SGT_PULL = 1,
	  SGT_PUSH,
	  } SGT;

struct stringgetter {
  SGT type;
  union {
    struct {
      unsigned char *b;
      int a;
      int (*get)(void *);
      int (*term)(unsigned char, void *);
      void *arg;
      } pull;
    struct {
      unsigned char *b;
      int a;
      int n;
      void (*done)(STRINGGOT, void *);
      int (*term)(unsigned char, void *);
      void *arg;
      } push;
    } ;
  } ;

STRINGGETTER *sg_init_pull(int (*get)(void *), int (*term)(unsigned char, void *), void *arg)
{
 STRINGGETTER *g;

 g = malloc(sizeof(STRINGGETTER));
 g->type = SGT_PULL;
 g->pull.b = 0;
 g->pull.a = 0;
 g->pull.get = get;
 g->pull.term = term;
 g->pull.arg = arg;
 return(g);
}

STRINGGETTER *sg_init_push(void (*done)(STRINGGOT, void *), int (*term)(unsigned char, void *), void *arg)
{
 STRINGGETTER *g;

 g = malloc(sizeof(STRINGGETTER));
 g->type = SGT_PUSH;
 g->push.b = 0;
 g->push.a = 0;
 g->push.n = 0;
 g->push.done = done;
 g->push.term = term;
 g->push.arg = arg;
 return(g);
}

void sg_done(STRINGGETTER *g)
{
 switch (g->type)
  { case SGT_PULL:
       free(g->pull.b);
       break;
    case SGT_PUSH:
       free(g->push.b);
       break;
    default:
       abort();
       break;
  }
 free(g);
}

STRINGGOT sg_get(STRINGGETTER *g)
{
 int l;
 int c;
 STRINGGOT rv;

 void save(unsigned char ch)
  { if (l >= g->pull.a) g->pull.b = realloc(g->pull.b,g->pull.a=l+8);
    g->pull.b[l++] = ch;
  }

 if (g->type != SGT_PULL) abort();
 l = 0;
 while (1)
  { c = (*g->pull.get)(g->pull.arg);
    if (c == EOF)
     { rv.len = -1;
       rv.str = 0;
       return(rv);
     }
    if ((*g->pull.term)(c,g->pull.arg))
     { rv.len = l;
       save('\0');
       rv.str = g->pull.b;
       return(rv);
     }
    save(c);
  }
}

void sg_put(STRINGGETTER *g, int ch)
{
 void save(unsigned char ch)
  { if (g->push.n >= g->push.a) g->push.b = realloc(g->push.b,g->push.a=g->push.n+8);
    g->push.b[g->push.n++] = ch;
  }

 if (g->type != SGT_PUSH) abort();
 if (ch == EOF)
  { (*g->push.done)((STRINGGOT){.len=-1,.str=0},g->push.arg);
    return;
  }
 if ((*g->push.term)(ch,g->push.arg))
  { save('\0');
    (*g->push.done)((STRINGGOT){.len=g->push.n-1,.str=g->push.b},g->push.arg);
    g->push.n = 0;
  }
 else
  { save(ch);
  }
}

/* XXX shouldn't have to cast arg to getc, but it's a macro. :-þ */
int sg_get_stdio(void *arg)
{
 return(getc((FILE *)arg));
}

int sg_term_nul(unsigned char ch, void *arg __attribute__((__unused__)))
{
 return(!ch);
}

int sg_term_nl(unsigned char ch, void *arg __attribute__((__unused__)))
{
 return(ch=='\n');
}