Implement av_strerror().

Originally committed as revision 22684 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/error.c

@@ -0,0 +1,46 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avutil.h"
+#include "avstring.h"
+
+int av_strerror(int errnum, char *errbuf, size_t errbuf_size)
+{
+    int ret = 0;
+    const char *errstr = NULL;
+
+    switch (errnum) {
+    case AVERROR_EOF:               errstr = "End of file"; break;
+    case AVERROR_INVALIDDATA:       errstr = "Invalid data found when processing input"; break;
+    case AVERROR_NOTSUPP:           errstr = "Operation not supported"; break;
+    case AVERROR_NUMEXPECTED:       errstr = "Number syntax expected in filename"; break;
+    case AVERROR_PATCHWELCOME:      errstr = "Not yet implemented in FFmpeg, patches welcome"; break;
+    }
+
+    if (errstr) {
+        av_strlcpy(errbuf, errstr, errbuf_size);
+    } else {
+#if HAVE_STRERROR_R
+        ret = strerror_r(AVUNERROR(errnum), errbuf, errbuf_size);
+#else
+        snprintf(errbuf, errbuf_size, "Error number %d occurred", errnum);
+#endif
+    }
+
+    return ret;
+}