jas_stream.c

DIGITAL IMAGERY is pervasive in our world today. Consequently, standards for the efficient represen

	int c;

	/* The stream must not be in an error or EOF state. */
	if ((stream->flags_ & (JAS_STREAM_ERRMASK)) != 0) {
		return EOF;
	}

	/* The stream must be open for reading. */
	if ((stream->openmode_ & JAS_STREAM_READ) == 0) {
		return EOF;
	}

	/* Make a half-hearted attempt to confirm that the buffer is not
	currently being used for writing.  This check is not intended
	to be foolproof! */
	assert((stream->bufmode_ & JAS_STREAM_WRBUF) == 0);

	assert(stream->ptr_ - stream->bufstart_ <= stream->bufsize_);

	/* Mark the buffer as being used for reading. */
	stream->bufmode_ |= JAS_STREAM_RDBUF;

	/* Read new data into the buffer. */
	stream->ptr_ = stream->bufstart_;
	if ((stream->cnt_ = (*stream->ops_->read_)(stream->obj_,
	  (char *) stream->bufstart_, stream->bufsize_)) <= 0) {
		if (stream->cnt_ < 0) {
			stream->flags_ |= JAS_STREAM_ERR;
		} else {
			stream->flags_ |= JAS_STREAM_EOF;
		}
		stream->cnt_ = 0;
		return EOF;
	}

	assert(stream->cnt_ > 0);
	/* Get or peek at the first character in the buffer. */
	c = (getflag) ? jas_stream_getc2(stream) : (*stream->ptr_);

	return c;
}

int jas_stream_flushbuf(jas_stream_t *stream, int c)
{
	int len;
	int n;

	/* The stream should not be in an error or EOF state. */
	if ((stream->flags_ & (JAS_STREAM_ERRMASK)) != 0) {
		return EOF;
	}

	/* The stream must be open for writing. */
	if ((stream->openmode_ & (JAS_STREAM_WRITE | JAS_STREAM_APPEND)) == 0) {
		return EOF;
	}

	/* The buffer should not currently be in use for reading. */
	assert(!(stream->bufmode_ & JAS_STREAM_RDBUF));

	/* Note: Do not use the quantity stream->cnt to determine the number
	of characters in the buffer!  Depending on how this function was
	called, the stream->cnt value may be "off-by-one". */
	len = stream->ptr_ - stream->bufstart_;
	if (len > 0) {
		n = (*stream->ops_->write_)(stream->obj_, (char *)
		  stream->bufstart_, len);
		if (n != len) {
			stream->flags_ |= JAS_STREAM_ERR;
			return EOF;
		}
	}
	stream->cnt_ = stream->bufsize_;
	stream->ptr_ = stream->bufstart_;

	stream->bufmode_ |= JAS_STREAM_WRBUF;

	if (c != EOF) {
		assert(stream->cnt_ > 0);
		return jas_stream_putc2(stream, c);
	}

	return 0;
}

/******************************************************************************\
* Miscellaneous code.
\******************************************************************************/

static int jas_strtoopenmode(const char *s)
{
	int openmode = 0;
	while (*s != '\0') {
		switch (*s) {
		case 'r':
			openmode |= JAS_STREAM_READ;
			break;
		case 'w':
			openmode |= JAS_STREAM_WRITE | JAS_STREAM_CREATE;
			break;
		case 'b':
			openmode |= JAS_STREAM_BINARY;
			break;
		case 'a':
			openmode |= JAS_STREAM_APPEND;
			break;
		case '+':
			openmode |= JAS_STREAM_READ | JAS_STREAM_WRITE;
			break;
		default:
			break;
		}
		++s;
	}
	return openmode;
}

int jas_stream_copy(jas_stream_t *out, jas_stream_t *in, int n)
{
	int all;
	int c;
	int m;

	all = (n < 0) ? 1 : 0;

	m = n;
	while (all || m > 0) {
		if ((c = jas_stream_getc_macro(in)) == EOF) {
			/* The next character of input could not be read. */
			/* Return with an error if an I/O error occured
			  (not including EOF) or if an explicit copy count
			  was specified. */
			return (!all || jas_stream_error(in)) ? (-1) : 0;
		}
		if (jas_stream_putc_macro(out, c) == EOF) {
			return -1;
		}
		--m;
	}
	return 0;
}

long jas_stream_setrwcount(jas_stream_t *stream, long rwcnt)
{
	int old;

	old = stream->rwcnt_;
	stream->rwcnt_ = rwcnt;
	return old;
}

int jas_stream_display(jas_stream_t *stream, FILE *fp, int n)
{
	unsigned char buf[16];
	int i;
	int j;
	int m;
	int c;
	int display;
	int cnt;

	cnt = n - (n % 16);
	display = 1;

	for (i = 0; i < n; i += 16) {
		if (n > 16 && i > 0) {
			display = (i >= cnt) ? 1 : 0;
		}
		if (display) {
			fprintf(fp, "%08x:", i);
		}
		m = JAS_MIN(n - i, 16);
		for (j = 0; j < m; ++j) {
			if ((c = jas_stream_getc(stream)) == EOF) {
				abort();
				return -1;
			}
			buf[j] = c;
		}
		if (display) {
			for (j = 0; j < m; ++j) {
				fprintf(fp, " %02x", buf[j]);
			}
			fputc(' ', fp);
			for (; j < 16; ++j) {
				fprintf(fp, "   ");
			}
			for (j = 0; j < m; ++j) {
				if (isprint(buf[j])) {
					fputc(buf[j], fp);
				} else {
					fputc(' ', fp);
				}
			}
			fprintf(fp, "\n");
		}


	}
	return 0;
}

long jas_stream_length(jas_stream_t *stream)
{
	long oldpos;
	long pos;
	if ((oldpos = jas_stream_tell(stream)) < 0) {
		return -1;
	}
	if (jas_stream_seek(stream, 0, SEEK_END) < 0) {
		return -1;
	}
	if ((pos = jas_stream_tell(stream)) < 0) {
		return -1;
	}
	if (jas_stream_seek(stream, oldpos, SEEK_SET) < 0) {
		return -1;
	}
	return pos;
}

/******************************************************************************\
* Memory stream object.
\******************************************************************************/

static int mem_read(jas_stream_obj_t *obj, char *buf, int cnt)
{
	int n;
	jas_stream_memobj_t *m = (jas_stream_memobj_t *)obj;
	n = m->len_ - m->pos_;
	cnt = JAS_MIN(n, cnt);
	memcpy(buf, &m->buf_[m->pos_], cnt);
	m->pos_ += cnt;
	return cnt;
}

static int mem_resize(jas_stream_memobj_t *m, int bufsize)
{
	unsigned char *buf;

	assert(m->buf_);
	if (!(buf = jas_realloc(m->buf_, bufsize * sizeof(unsigned char)))) {
		return -1;
	}
	m->buf_ = buf;
	m->bufsize_ = bufsize;
	return 0;
}

static int mem_write(jas_stream_obj_t *obj, char *buf, int cnt)
{
	int n;
	int ret;
	jas_stream_memobj_t *m = (jas_stream_memobj_t *)obj;
	long newbufsize;
	long newpos;

	newpos = m->pos_ + cnt;
	if (newpos > m->bufsize_ && m->growable_) {
		newbufsize = m->bufsize_;
		while (newbufsize < newpos) {
			newbufsize <<= 1;
			assert(newbufsize >= 0);
		}
		if (mem_resize(m, newbufsize)) {
			return -1;
		}
	}
	if (m->pos_ > m->len_) {
		/* The current position is beyond the end of the file, so
		  pad the file to the current position with zeros. */
		n = JAS_MIN(m->pos_, m->bufsize_) - m->len_;
		if (n > 0) {
			memset(&m->buf_[m->len_], 0, n);
			m->len_ += n;
		}
		if (m->pos_ != m->len_) {
			/* The buffer is not big enough. */
			return 0;
		}
	}
	n = m->bufsize_ - m->pos_;
	ret = JAS_MIN(n, cnt);
	if (ret > 0) {
		memcpy(&m->buf_[m->pos_], buf, ret);
		m->pos_ += ret;
	}
	if (m->pos_ > m->len_) {
		m->len_ = m->pos_;
	}
assert(ret == cnt);
	return ret;
}

static long mem_seek(jas_stream_obj_t *obj, long offset, int origin)
{
	jas_stream_memobj_t *m = (jas_stream_memobj_t *)obj;
	long newpos;

	switch (origin) {
	case SEEK_SET:
		newpos = offset;
		break;
	case SEEK_END:
		newpos = m->len_ - offset;
		break;
	case SEEK_CUR:
		newpos = m->pos_ + offset;
		break;
	default:
		abort();
		break;
	}
	if (newpos < 0) {
		return -1;
	}
	m->pos_ = newpos;

	return m->pos_;
}

static int mem_close(jas_stream_obj_t *obj)
{
	jas_stream_memobj_t *m = (jas_stream_memobj_t *)obj;
	if (m->myalloc_ && m->buf_) {
		jas_free(m->buf_);
		m->buf_ = 0;
	}
	jas_free(obj);
	return 0;
}

/******************************************************************************\
* File stream object.
\******************************************************************************/

static int file_read(jas_stream_obj_t *obj, char *buf, int cnt)
{
	jas_stream_fileobj_t *fileobj = JAS_CAST(jas_stream_fileobj_t *, obj);
	return read(fileobj->fd, buf, cnt);
}

static int file_write(jas_stream_obj_t *obj, char *buf, int cnt)
{
	jas_stream_fileobj_t *fileobj = JAS_CAST(jas_stream_fileobj_t *, obj);
	return write(fileobj->fd, buf, cnt);
}

static long file_seek(jas_stream_obj_t *obj, long offset, int origin)
{
	jas_stream_fileobj_t *fileobj = JAS_CAST(jas_stream_fileobj_t *, obj);
	return lseek(fileobj->fd, offset, origin);
}

static int file_close(jas_stream_obj_t *obj)
{
	jas_stream_fileobj_t *fileobj = JAS_CAST(jas_stream_fileobj_t *, obj);
	int ret;
	ret = close(fileobj->fd);
	if (fileobj->flags & JAS_STREAM_FILEOBJ_DELONCLOSE) {
		unlink(fileobj->pathname);
	}
	jas_free(fileobj);
	return ret;
}

/******************************************************************************\
* Stdio file stream object.
\******************************************************************************/

static int sfile_read(jas_stream_obj_t *obj, char *buf, int cnt)
{
	FILE *fp;
	fp = JAS_CAST(FILE *, obj);
	return fread(buf, 1, cnt, fp);
}

static int sfile_write(jas_stream_obj_t *obj, char *buf, int cnt)
{
	FILE *fp;
	fp = JAS_CAST(FILE *, obj);
	return fwrite(buf, 1, cnt, fp);
}

static long sfile_seek(jas_stream_obj_t *obj, long offset, int origin)
{
	FILE *fp;
	fp = JAS_CAST(FILE *, obj);
	return fseek(fp, offset, origin);
}

static int sfile_close(jas_stream_obj_t *obj)
{
	FILE *fp;
	fp = JAS_CAST(FILE *, obj);
	return fclose(fp);
}