Add FileGroup.

2 files changed, 206 insertions, 0 deletions

diff --git a/src/lib/file_group.cc b/src/lib/file_group.cc
new file mode 100644
index 000000000..5f9531f4c
--- /dev/null
+++ b/src/lib/file_group.cc
@@ -0,0 +1,160 @@
+/*
+    Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
+
+    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 2 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, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <cstdio>
+extern "C" {
+#include <libavformat/avio.h>
+}
+#include <sndfile.h>
+#include "file_group.h"
+#include "exceptions.h"
+
+using std::vector;
+using std::cout;
+
+FileGroup::FileGroup (boost::filesystem::path p)
+	: _current_path (0)
+	, _current_file (0)
+{
+	_paths.push_back (p);
+	seek (0, SEEK_SET);
+}
+
+FileGroup::FileGroup (vector<boost::filesystem::path> const & p)
+	: _paths (p)
+	, _current_path (0)
+	, _current_file (0)
+{
+	ensure_open_path (0);
+	seek (0, SEEK_SET);
+}
+
+FileGroup::~FileGroup ()
+{
+	if (_current_file) {
+		fclose (_current_file);
+	}
+}
+
+
+/** Ensure that the given path index in the content is the _current_file */
+void
+FileGroup::ensure_open_path (size_t p) const
+{
+	if (_current_file && _current_path == p) {
+		/* Already open */
+		return;
+	}
+	
+	if (_current_file) {
+		fclose (_current_file);
+	}
+
+	_current_path = p;
+	_current_file = fopen (_paths[_current_path].string().c_str(), "rb");
+	if (_current_file == 0) {
+		throw OpenFileError (_paths[_current_path]);
+	}
+}
+
+int64_t
+FileGroup::seek (int64_t pos, int whence) const
+{
+	int64_t const len = length ();
+	
+	/* Convert pos to `full_pos', which is an offset from the start
+	   of all the files.
+	*/
+	int64_t full_pos = 0;
+	switch (whence) {
+	case SEEK_SET:
+		full_pos = pos;
+		break;
+	case SEEK_CUR:
+		for (size_t i = 0; i < _current_path; ++i) {
+			full_pos += boost::filesystem::file_size (_paths[i]);
+		}
+		full_pos += ftell (_current_file);
+		full_pos += pos;
+		break;
+	case SEEK_END:
+		full_pos = len - pos;
+		break;
+	case AVSEEK_SIZE:
+		return len;
+	}
+
+	/* Seek to full_pos */
+	size_t i = 0;
+	int64_t sub_pos = full_pos;
+	while (i < _paths.size ()) {
+		boost::uintmax_t len = boost::filesystem::file_size (_paths[i]);
+		if (sub_pos < int64_t (len)) {
+			break;
+		}
+		sub_pos -= len;
+		++i;
+	}
+
+	if (i == _paths.size ()) {
+		return -1;
+	}
+
+	ensure_open_path (i);
+	fseek (_current_file, sub_pos, SEEK_SET);
+	return full_pos;
+}
+
+/** Try to read some data from the current position into a buffer.
+ *  @param buffer Buffer to write data into.
+ *  @param amount Number of bytes to read.
+ *  @return Number of bytes read, or -1 in the case of error.
+ */
+int
+FileGroup::read (uint8_t* buffer, int amount) const
+{
+	int read = 0;
+	while (1) {
+		int const this_time = fread (buffer + read, 1, amount - read, _current_file);
+		read += this_time;
+		if (read == amount) {
+			/* Done */
+			break;
+		}
+
+		/* See if there is another file to use */
+		if ((_current_path + 1) >= _paths.size()) {
+			break;
+		}
+		ensure_open_path (_current_path + 1);
+	}
+
+	return read;
+}
+
+int64_t
+FileGroup::length () const
+{
+	int64_t len = 0;
+	for (size_t i = 0; i < _paths.size(); ++i) {
+		len += boost::filesystem::file_size (_paths[i]);
+	}
+
+	return len;
+}
diff --git a/src/lib/file_group.h b/src/lib/file_group.h
new file mode 100644
index 000000000..99803d386
--- /dev/null
+++ b/src/lib/file_group.h
@@ -0,0 +1,46 @@
+/*
+    Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
+
+    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 2 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, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef DCPOMATIC_FILE_GROUP_H
+#define DCPOMATIC_FILE_GROUP_H
+
+#include <vector>
+#include <boost/filesystem.hpp>
+
+class FileGroup
+{
+public:
+	FileGroup (boost::filesystem::path);
+	FileGroup (std::vector<boost::filesystem::path> const &);
+	~FileGroup ();
+
+	int64_t seek (int64_t, int) const;
+	int read (uint8_t*, int) const;
+	int64_t length () const;
+
+private:
+	void ensure_open_path (size_t) const;
+
+	std::vector<boost::filesystem::path> _paths;
+	/** Index of path that we are currently reading from */
+	mutable size_t _current_path;
+	mutable FILE* _current_file;
+};
+
+#endif