/* ioutils version 1.0 by Andrew Poelstra */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>

#include "ioutils.h"

/* Reads from fh into buff (buff may be NULL, in which case characters  *
 * are discarded), up until it reaches either stop_c or whitespace. (In *
 * the special case that the first character is a quote, it will simply *
 * read everything until it reaches an end quote.) Unless buff is NULL, *
 * it reads at most (maxlen-1) characters and null-terminates buff. If  *
 * count is non-NULL, it will be filled with the number of characters   *
 * read. Returns 0 on success or EOF on error.                          */
int gets_ws (char *buff, size_t *count, size_t maxlen, char stop_c, FILE *fh)
{
  size_t i = 0;
  int err = (fh == NULL);
  int stop_white = 1;
  int ch  = err ? EOF : getc (fh);
  int pch = ch;

  switch (ch)
  {
    case '\"':
    case '\'':
    case '`':
      stop_white = 0;
      stop_c = ch;
      break;
    case EOF:
      err = 1;
  }

  while ((!stop_white || !isspace (ch)) &&
         (!buff || i < maxlen) &&
         (ch != stop_c || pch == '\\'))
  {
    pch = ch;
    if (buff && i < maxlen)
      buff[i++] = ch;

    if (ch == EOF)
    {
      err = (ch == EOF);
      ch = stop_c;
    } else {
      ch = getc (fh);
    }
    ++i;
  }

  if (count != NULL)
    *count = i;

  /* We need to check in case maxlen is 0. */
  if (buff && maxlen)
    buff[i] = 0;

  ungetc (ch, fh);
  return err ? EOF : 0;
}

/* Kinda obvious: skips all whitespace in stream and returns first non-white
 * character. (The first non-white character is put back into the stream for
 * further parsing.) */
int skip_white (FILE *stream)
{
  int ch;
  if (!stream)
    return EOF;

  ch = getc (stream);
  while (ch != EOF && isspace (ch))
    ch = getc (stream);

  ungetc (ch, stream);
  return ch;
}

/* Reads from stream lines such as
 *   tagname "Tag value here"
 * allowing for unlimited whitespace and a colon at the end of tagname. */

int gets_tv (FILE *stream, char *tag_name, char *tag_value,
             size_t name_max, size_t value_max)
{
  int erred = 0;

  if (!erred) erred = (skip_white (stream) == EOF);
  if (!erred) erred = gets_ws (tag_name, NULL, name_max, ':', stream);
  if (!erred) erred = gets_ws (NULL, NULL, 0, ':', stream);  /* Flush buffer. */

  if (!erred) erred = (skip_white (stream) == EOF);
  if (!erred) erred = gets_ws (tag_value, NULL, value_max, 0, stream);
  if (!erred) erred = gets_ws (NULL, NULL, 0, 0, stream);  /* Flush buffer. */

  return erred;
}

/* Warning: *nix specific function; must be rewritten for other OSes.
 * The Windows equivilant would return "%APPDATA%[suffix]" perhaps.
 * suffix should be of the form /dir/file (with a preceding slash) */
char *home_fname (char *suffix)
{
  char *tmpptr = getenv ("HOME");
  char *retptr;
  size_t len  = suffix ? strlen (suffix) : 0;
         len += tmpptr ? strlen (tmpptr) : 0;

  retptr = malloc (len + 1);
  if (retptr)
  {
    if (tmpptr)
      strcpy (retptr, tmpptr);
    else
      *retptr = 0;

    if (suffix)
      strcat (retptr, suffix);
  }

  return retptr;
}