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

#include "memstream.h"

typedef struct chunk CHUNK;

struct chunk {
  CHUNK *link;
  unsigned char data[8000];
  int fill;
  } ;

struct memstream {
  CHUNK *chunks;
  CHUNK **chunkt;
  CHUNK *wcur;
  CHUNK *rcur;
  int rptr;
  int totalsize;
  } ;

static void append_new_chunk(MEMSTREAM *m)
{
 m->wcur = malloc(sizeof(CHUNK));
 *m->chunkt = m->wcur;
 m->chunkt = &m->wcur->link;
 m->wcur->fill = 0;
 m->rptr = 0;
 m->totalsize = 0;
}

MEMSTREAM *memstream_open_w(void)
{
 MEMSTREAM *m;

 m = malloc(sizeof(MEMSTREAM));
 m->chunks = 0;
 m->chunkt = &m->chunks;
 m->wcur = 0;
 m->rcur = 0;
 return(m);
}

void memstream_append(MEMSTREAM *m, const void *data, int len)
{
 const char *dp;
 int n;

 if (len < 1) return;
 if (m->wcur == 0) append_new_chunk(m);
 dp = data;
 while (1)
  { n = sizeof(m->wcur->data) - m->wcur->fill;
    if (len <= n)
     { bcopy(dp,&m->wcur->data[m->wcur->fill],len);
       m->wcur->fill += len;
       m->totalsize += len;
       break;
     }
    bcopy(dp,&m->wcur->data[m->wcur->fill],n);
    m->wcur->fill += n;
    m->totalsize += n;
    append_new_chunk(m);
    dp += n;
    len -= n;
  }
}

void memstream_dump(MEMSTREAM *m, void (*each)(const void *, int))
{
 CHUNK *c;

 for (c=m->chunks;c;c=c->link) (*each)(&c->data[0],c->fill);
}

unsigned int memstream_size(MEMSTREAM *m)
{
 return(m->totalsize);
}

extern void memstream_free(MEMSTREAM *m)
{
 CHUNK *c;

 while (1)
  { c = m->chunks;
    if (! c) break;
    m->chunks = c->link;
    free(c);
  }
 free(m);
}