/************************************************************************
 *	Routines to deal with the header-field objects in formail	*
 *									*
 *	Copyright (c) 1990-1994, S.R. van den Berg, The Netherlands	*
 *	#include "../README"						*
 ************************************************************************/
#ifdef RCS
static /*const*/char rcsid[]=
 "$Id: fields.c,v 1.17 1994/06/28 16:56:07 berg Exp $";
#endif
#include "includes.h"
#include "formail.h"
#include "sublib.h"
#include "shell.h"
#include "common.h"
#include "fields.h"
#include "ecommon.h"
#include "formisc.h"
				/* find a field in the linked list of fields */
struct field*findf(p,ah)const struct field*const p;register struct field**ah;
{ size_t i;int uhead;char*chp;register struct field*h;
  uhead=ah==&uheader||ah==&Uheader;
  for(i=p->id_len,chp=(char*)p->fld_text,h= *ah;h;h= *(ah= &h->fld_next))
     if(i>=h->id_len&&!strnIcmp(chp,h->fld_text,h->id_len))
      { if(i>h->id_len&&uhead)			     /* finalise the header? */
	   *ah=0,(*(ah=addfield(ah,chp,i)))->fld_next=h,(h= *ah)->fld_ref=0;
	return h;
      }
  return (struct field*)0;
}

void clear_uhead(hdr)register struct field*hdr;
{ for(;hdr;hdr=hdr->fld_next)
     hdr->fld_ref=0;
}

struct field**addfield(pointer,text,totlen)struct field**pointer;
 const char*const text;const size_t totlen;    /* add field to a linked list */
{ register struct field*p,**pp;int idlen;
  for(pp=pointer;*pp;pp= &(*pp)->fld_next);   /* skip to the end of the list */
  (*pp=p=malloc(FLD_HEADSIZ+totlen))->fld_next=0;idlen=breakfield(text,totlen);
  p->id_len=idlen>0?idlen:pp==&rdheader?0:-idlen;	    /* copy contents */
  tmemmove(p->fld_text,text,p->tot_len=totlen);
  return pp;
}

struct field*delfield(pointer)struct field**pointer;
{ struct field*fldp;
  *pointer=(fldp= *pointer)->fld_next;free(fldp);
  return *pointer;
}

void concatenate(fldp)struct field*const fldp;
{ register char*p;register size_t l;	    /* concatenate a continued field */
  l=fldp->tot_len;
  if(!eqFrom_(p=fldp->fld_text))	    /* don't concatenate From_ lines */
     while(l--)
	if(*p++=='\n'&&l)    /* by substituting all newlines except the last */
	   p[-1]=' ';
}

void renfield(pointer,oldl,newname,newl)struct field**const pointer;
 const size_t oldl,newl;const char*const newname;	    /* rename fields */
{ struct field*p;size_t i;char*chp;
  i=(p= *pointer)->tot_len-oldl;	      /* length of what we will keep */
  *pointer=p=realloc(p,FLD_HEADSIZ+(p->tot_len=i+newl));chp=p->fld_text;
  tmemmove(chp+newl,chp+oldl,i);tmemmove(chp,newname,newl);   /* shove, copy */
}

static void extractfield(p)register struct field*p;
{ if(xheader||Xheader)					 /* extracting only? */
   { if(findf(p,&xheader))			   /* extract field contents */
      { putssn((char*)p->fld_text+p->id_len,p->tot_len-p->id_len);
	return;
      }
     if(!findf(p,&Xheader))				   /* extract fields */
	return;
   }
  lputssn(p->fld_text,p->tot_len);		      /* display it entirely */
}

void flushfield(pointer)register struct field**pointer;	 /* delete and print */
{ register struct field*p,*q;				   /* them as you go */
  for(p= *pointer,*pointer=0;p;p=q)
     q=p->fld_next,extractfield(p),free(p);
}

void dispfield(p)register const struct field*p;
{ for(;p;p=p->fld_next)			     /* print list non-destructively */
     if(p->id_len+1<p->tot_len)			 /* any contents to display? */
	extractfield(p);
}
		    /* try and append one valid field to rdheader from stdin */
int readhead P((void))
{ getline();
  if(eqFrom_(buf))					/* it's a From_ line */
   { if(rdheader)
	return 0;			       /* the From_ line was a fake! */
     for(;buflast=='>';getline());	    /* gather continued >From_ lines */
   }
  else
   { if(breakfield(buf,buffilled)<=0)	   /* not the start of a valid field */
	return 0;
     for(;;getline())		      /* get the rest of the continued field */
      { switch(buflast)			     /* will this line be continued? */
	 { case ' ':case '\t':				  /* yep, it sure is */
	      continue;
	 }
	break;
      }
   }
  addbuf();			  /* phew, got the field, add it to rdheader */
  return 1;
}

void addbuf P((void))
{ addfield(&rdheader,buf,buffilled);buffilled=0;
}