#include <string.h>
#include <time.h>

#include "postgres.h"
#include "utils/palloc.h"

typedef struct varlena varchar;

varchar *c_strftime(int now, varchar *fmt_in)
{
  char tmpbuf[128];
  char *fmt;
  struct tm *mytm;
  int len;
  int32 new_text_size;
  varchar *new_text;

  /* Copy incoming format string to null-terminated C string */
  fmt = (char *)palloc(VARSIZE(fmt_in) - VARHDRSZ + 1);
  memcpy((void *)fmt, (void *)VARDATA(fmt_in), VARSIZE(fmt_in) - VARHDRSZ);
  fmt[VARSIZE(fmt_in) - VARHDRSZ] = '\0';
  
  /* Call strftime().  XXX portability and buffer complications; see
     Perl source POSIX.xs for ideas. */
  mytm = localtime((const time_t *)&now);
  len = strftime(tmpbuf, sizeof tmpbuf, fmt, mytm);
  pfree(fmt);

  /* Copy the output into a Postgres varchar */
  new_text_size = len + VARHDRSZ;
  new_text = (varchar *)palloc(new_text_size);
  memset((void *)new_text, 0, new_text_size);
  VARSIZE(new_text) = new_text_size;

  if (len) {
    memcpy((void *)VARDATA(new_text), (void *)tmpbuf, len);
  }

  return new_text;
}