[iso] initial ISO image support (EXPERIMENTAL)

* from libcdio: http://www.gnu.org/software/libcdio/

src/libcdio/driver/_cdio_stream.c

@@ -0,0 +1,222 @@
+/*
+  Copyright (C) 2005, 2006, 2008, 2011 Rocky Bernstein <rocky@gnu.org>
+  Copyright (C) 2000, 2004, 2005 Herbert Valerio Riedel <hvr@gnu.org>
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+# define __CDIO_CONFIG_H__ 1
+#endif
+
+#ifdef HAVE_STDIO_H
+#include <stdio.h>
+#endif
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#ifdef HAVE_STDARG_H
+#include <stdarg.h>
+#endif
+#include "cdio_assert.h"
+
+/* #define STREAM_DEBUG  */
+
+#include <cdio/logging.h>
+#include <cdio/util.h>
+#include "_cdio_stream.h"
+
+static const char _rcsid[] = "$Id: _cdio_stream.c,v 1.9 2008/04/22 15:29:11 karl Exp $";
+
+/* 
+ * DataSource implementations
+ */
+
+struct _CdioDataSource {
+  void* user_data;
+  cdio_stream_io_functions op;
+  int is_open;
+  off_t position;
+};
+
+void
+cdio_stream_close(CdioDataSource_t *p_obj)
+{
+  if (!p_obj) return;
+
+  if (p_obj->is_open) {
+    cdio_debug ("closed source...");
+    p_obj->op.close(p_obj->user_data);
+    p_obj->is_open  = 0;
+    p_obj->position = 0;
+  }
+}
+
+void
+cdio_stream_destroy(CdioDataSource_t *p_obj)
+{
+  if (!p_obj) return;
+
+  cdio_stream_close(p_obj);
+
+  p_obj->op.free(p_obj->user_data);
+
+  free(p_obj);
+}
+
+/**
+  Like 3 fgetpos.
+  
+  This function gets the current file position indicator for the stream
+  pointed to by stream.  
+  
+  @return unpon successful completion, return value is positive, else,
+  the global variable errno is set to indicate the error.
+*/
+off_t
+cdio_stream_getpos(CdioDataSource_t* p_obj, /*out*/ off_t *i_offset)
+{
+  if (!p_obj || !p_obj->is_open) return DRIVER_OP_UNINIT;
+  return *i_offset = p_obj->position;
+}
+
+CdioDataSource_t *
+cdio_stream_new(void *user_data, const cdio_stream_io_functions *funcs)
+{
+  CdioDataSource_t *new_obj;
+
+  new_obj = calloc (1, sizeof (CdioDataSource_t));
+
+  new_obj->user_data = user_data;
+  memcpy(&(new_obj->op), funcs, sizeof(cdio_stream_io_functions));
+
+  return new_obj;
+}
+
+/* 
+   Open if not already open. 
+   Return false if we hit an error. Errno should be set for that error.
+*/
+static bool
+_cdio_stream_open_if_necessary(CdioDataSource_t *p_obj)
+{
+  if (!p_obj) return false;
+
+  if (!p_obj->is_open) {
+    if (p_obj->op.open(p_obj->user_data)) {
+      cdio_warn ("could not open input stream...");
+      return false;
+    } else {
+      cdio_debug ("opened source...");
+      p_obj->is_open = 1;
+      p_obj->position = 0;
+    }
+  }
+  return true;
+}
+
+/**
+  Like fread(3) and in fact may be the same.
+  
+  DESCRIPTION:
+  The function fread reads nmemb elements of data, each size bytes long,
+  from the stream pointed to by stream, storing them at the location
+  given by ptr.
+  
+  RETURN VALUE:
+  return the number of items successfully read or written (i.e.,
+  not the number of characters).  If an error occurs, or the
+  end-of-file is reached, the return value is a short item count
+  (or zero).
+  
+  We do not distinguish between end-of-file and error, and callers
+  must use feof(3) and ferror(3) to determine which occurred.
+*/
+ssize_t
+cdio_stream_read(CdioDataSource_t* p_obj, void *ptr, size_t size, size_t nmemb)
+{
+  long read_bytes;
+
+  if (!p_obj) return 0;
+  if (!_cdio_stream_open_if_necessary(p_obj)) return 0;
+
+  read_bytes = (p_obj->op.read)(p_obj->user_data, ptr, size*nmemb);
+  p_obj->position += read_bytes;
+
+  return read_bytes;
+}
+
+/**
+  Like 3 fseek and in fact may be the same.
+  
+  This  function sets the file position indicator for the stream
+  pointed to by stream.  The new position, measured in bytes, is obtained
+  by  adding offset bytes to the position specified by whence.  If whence
+  is set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset  is  relative  to
+  the  start of the file, the current position indicator, or end-of-file,
+  respectively.  A successful call to the fseek function clears the end-
+  of-file indicator for the stream and undoes any effects of the
+  ungetc(3) function on the same stream.
+  
+  @return unpon successful completion, return value is positive, else,
+  the global variable errno is set to indicate the error.
+*/
+int
+cdio_stream_seek(CdioDataSource_t* p_obj, off_t offset, int whence)
+{
+  if (!p_obj) return DRIVER_OP_UNINIT;
+
+  if (!_cdio_stream_open_if_necessary(p_obj)) 
+    /* errno is set by _cdio_stream_open_if necessary. */
+    return DRIVER_OP_ERROR;
+
+  if (offset < 0) return DRIVER_OP_ERROR;
+  if (p_obj->position < 0) return DRIVER_OP_ERROR;
+
+  if (p_obj->position != offset) {
+#ifdef STREAM_DEBUG
+    cdio_warn("had to reposition DataSource from %ld to %ld!", p_obj->position, offset);
+#endif
+    p_obj->position = offset;
+    return p_obj->op.seek(p_obj->user_data, offset, whence);
+  }
+
+  return 0;
+}
+
+/**
+  Return whatever size of stream reports, I guess unit size is bytes. 
+  On error return -1;
+ */
+off_t
+cdio_stream_stat(CdioDataSource_t *p_obj)
+{
+  if (!p_obj) return -1;
+  if (!_cdio_stream_open_if_necessary(p_obj)) return -1;
+
+  return p_obj->op.stat(p_obj->user_data);
+}
+
+
+/* 
+ * Local variables:
+ *  c-file-style: "gnu"
+ *  tab-width: 8
+ *  indent-tabs-mode: nil
+ * End:
+ */