start abstracting input layer for decoders

git-svn-id: https://svn.musicpd.org/mpd/trunk@903 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/inputStream.c

@@ -0,0 +1,78 @@
+/* the Music Player Daemon (MPD)
+ * (c)2003-2004 by Warren Dukes (shank@mercury.chem.pitt.edu)
+ * This project's homepage is: http://www.musicpd.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 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "inputStream.h"
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+
+int initInputStreamFromFile(InputStream * inStream, char * filename) {
+	inStream->fp = fopen(filename,"r");
+	if(!inStream->fp) {
+		inStream->error = errno;
+		return -1;
+	}
+
+	inStream->offset = 0;
+
+	fseek(inStream->fp,0,SEEK_END);
+	inStream->size = ftell(inStream->fp);
+	fseek(inStream->fp,0,SEEK_SET);
+
+	return 0;
+}
+
+int seekInputStream(InputStream * inStream, long offset) {
+	if(offset<0) {
+		inStream->error = EINVAL;
+		return -1;
+	}
+
+	if(fseek(inStream->fp,offset,SEEK_SET)==0) {
+		inStream->offset = offset;
+	}
+	else {
+		inStream->error = errno;
+		return -1;
+	}
+
+	return 0;
+}
+
+size_t fillBufferFromInputStream(InputStream * inStream, char * buffer, 
+		size_t buflen) 
+{
+	size_t readSize;
+
+	readSize = fread(buffer,1,buflen,inStream->fp);
+
+	if(readSize>0) inStream->offset+=readSize;
+
+	return readSize;
+}
+
+int finishInputStream(InputStream * inStream) {
+	if(fclose(inStream->fp)<0) {
+		inStream->error = errno;
+	}
+	else return -1;
+
+	return 0;
+}