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

#include <stdio.h>
#include <stdlib.h>
#include <linuxcompat.h>

#include "stdio-util.h"

typedef struct indent_priv INDENT_PRIV;

struct indent_priv {
  FILE *inner;
  int atnl;
  } ;

static int w_indent(void *pv, const char *data, int len)
{
 INDENT_PRIV *p;
 int atnl;
 FILE *f;
 int o;
 int o0;

 p = pv;
 atnl = p->atnl;
 f = p->inner;
 o0 = -1;
 for (o=0;o<len;o++)
  { if (atnl)
     { if (o0 >= 0) abort();
       putc('\t',f);
       atnl = 0;
     }
    if (data[o] == '\n')
     { if (o0 >= 0)
	{ fwrite(data+o0,1,(o+1)-o0,f);
	  o0 = -1;
	}
       atnl = 1;
     }
    else
     { if (o0 < 0) o0 = o;
       atnl = 0;
     }
  }
 if (o0 >= 0) fwrite(data+o0,1,o-o0,f);
 p->atnl = atnl;
 return(len);
}

static int c_indent(void *pv)
{
 free(pv);
 return(0);
}

FILE *fwrap_indent(FILE *inner)
{
 INDENT_PRIV *p;
 FILE *f;

 p = malloc(sizeof(INDENT_PRIV));
 if (! p) return(0);
 f = funopen(p,0,&w_indent,0,&c_indent);
 if (! f)
  { free(p);
    return(0);
  }
 p->inner = inner;
 p->atnl = 1;
 return(f);
}