From 35b092aaa718dcb12933effd33324bda5d3b5cce Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 21 Nov 2012 00:53:11 +0200
Subject: [PATCH] Add dedicated exception classes for decoding sounds

---
 source/oggdecoder.cpp   | 35 ++++++++++++++++++++++++++++++-----
 source/oggdecoder.h     | 12 ++++++++++++
 source/sounddecoder.cpp |  5 +++++
 source/sounddecoder.h   |  8 ++++++++
 4 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/source/oggdecoder.cpp b/source/oggdecoder.cpp
index a00b78e..5462b79 100644
--- a/source/oggdecoder.cpp
+++ b/source/oggdecoder.cpp
@@ -1,5 +1,5 @@
-#include <stdexcept>
 #include <vorbis/vorbisfile.h>
+#include <msp/strings/format.h>
 #include "oggdecoder.h"
 
 using namespace std;
@@ -48,6 +48,30 @@ ov_callbacks io_callbacks =
 namespace Msp {
 namespace AL {
 
+ogg_error::ogg_error(const std::string &func, int code):
+	runtime_error(format("%s: %s", func, get_message(code)))
+{ }
+
+string ogg_error::get_message(int code)
+{
+	switch(code)
+	{
+	case OV_FALSE: return "No data available";
+	case OV_HOLE: return "Missing or corrupt data";
+	case OV_EREAD: return "Read error";
+	case OV_EFAULT: return "Internal inconsistency";
+	case OV_EIMPL: return "Not implemented";
+	case OV_EINVAL: return "Invalid argument";
+	case OV_ENOTVORBIS: return "Not Vorbis data";
+	case OV_EBADHEADER: return "Corrupt Vorbis header";
+	case OV_EVERSION: return "Unsupported version";
+	case OV_EBADLINK: return "Bad link";
+	case OV_ENOSEEK: return "Stream is not seekable";
+	default: return format("Unknown error (%d)", code);
+	}
+}
+
+
 struct OggDecoder::Private
 {
 	OggVorbis_File ovfile;	
@@ -56,8 +80,9 @@ struct OggDecoder::Private
 OggDecoder::OggDecoder(IO::Seekable &io):
 	priv(new Private)
 {
-	if(ov_open_callbacks(&io, &priv->ovfile, 0, 0, io_callbacks)<0)
-		throw runtime_error("Could not open ogg vorbis resource");
+	int ret = ov_open_callbacks(&io, &priv->ovfile, 0, 0, io_callbacks);
+	if(ret<0)
+		throw ogg_error("ov_open_callbacks", ret);
 
 	vorbis_info *info = ov_info(&priv->ovfile, -1);
 	freq = info->rate;
@@ -68,7 +93,7 @@ OggDecoder::OggDecoder(IO::Seekable &io):
 	{
 	case 1: format = MONO16; break;
 	case 2: format = STEREO16; break;
-	default: throw runtime_error("Unsupported number of channels");
+	default: throw unsupported_sound(Msp::format("%d channels", info->channels));
 	}
 }
 
@@ -89,7 +114,7 @@ unsigned OggDecoder::read(char *buf, unsigned len)
 	int section = 0;
 	int res = ov_read(&priv->ovfile, buf, len, 0, 2, 1, &section);
 	if(res<0)
-		throw runtime_error("Error reading ogg vorbis file");
+		throw ogg_error("ov_read", res);
 	else if(res==0)
 		eof_flag = true;
 	return res;
diff --git a/source/oggdecoder.h b/source/oggdecoder.h
index a3f5504..49cadbb 100644
--- a/source/oggdecoder.h
+++ b/source/oggdecoder.h
@@ -1,11 +1,23 @@
 #ifndef MSP_AL_OGGDECODER_H_
 #define MSP_AL_OGGDECODER_H_
 
+#include <stdexcept>
 #include "sounddecoder.h"
 
 namespace Msp {
 namespace AL {
 
+class ogg_error: public std::runtime_error
+{
+public:
+	ogg_error(const std::string &, int);
+	virtual ~ogg_error() throw() { }
+
+private:
+	static std::string get_message(int);
+};
+
+
 class OggDecoder: public SoundDecoder
 {
 private:
diff --git a/source/sounddecoder.cpp b/source/sounddecoder.cpp
index 77e3b40..138117f 100644
--- a/source/sounddecoder.cpp
+++ b/source/sounddecoder.cpp
@@ -8,6 +8,11 @@ using namespace std;
 namespace Msp {
 namespace AL {
 
+unsupported_sound::unsupported_sound(const string &w):
+	runtime_error(w)
+{ }
+
+
 SoundDecoder::SoundDecoder():
 	source(0),
 	freq(0),
diff --git a/source/sounddecoder.h b/source/sounddecoder.h
index 7a08644..ee5b07d 100644
--- a/source/sounddecoder.h
+++ b/source/sounddecoder.h
@@ -8,6 +8,14 @@
 namespace Msp {
 namespace AL {
 
+class unsupported_sound: public std::runtime_error
+{
+public:
+	unsupported_sound(const std::string &);
+	virtual ~unsupported_sound() throw() { }
+};
+
+
 /**
 This class facilitates loading sound files.  Currently only Ogg Vorbis is
 supported.
-- 
2.43.0