--include/vorbis/codec.h from libvorbis 1.3.5
local ffi = require'ffi'
require'libogg_h'

ffi.cdef[[
typedef struct vorbis_info{
	int version;
	int channels;
	long rate;
	long bitrate_upper;
	long bitrate_nominal;
	long bitrate_lower;
	long bitrate_window;
	void *codec_setup;
} vorbis_info;
typedef struct vorbis_dsp_state{
	int analysisp;
	vorbis_info *vi;
	float **pcm;
	float **pcmret;
	int pcm_storage;
	int pcm_current;
	int pcm_returned;
	int preextrapolate;
	int eofflag;
	long lW;
	long W;
	long nW;
	long centerW;
	ogg_int64_t granulepos;
	ogg_int64_t sequence;
	ogg_int64_t glue_bits;
	ogg_int64_t time_bits;
	ogg_int64_t floor_bits;
	ogg_int64_t res_bits;
	void *backend_state;
} vorbis_dsp_state;
typedef struct vorbis_block{
	float **pcm;
	oggpack_buffer opb;
	long lW;
	long W;
	long nW;
	int pcmend;
	int mode;
	int eofflag;
	ogg_int64_t granulepos;
	ogg_int64_t sequence;
	vorbis_dsp_state *vd;
	void *localstore;
	long localtop;
	long localalloc;
	long totaluse;
	struct alloc_chain *reap;
	long glue_bits;
	long time_bits;
	long floor_bits;
	long res_bits;
	void *internal;
} vorbis_block;
struct alloc_chain{
	void *ptr;
	struct alloc_chain *next;
};
typedef struct vorbis_comment{
	char **user_comments;
	int *comment_lengths;
	int comments;
	char *vendor;
} vorbis_comment;
void vorbis_info_init(vorbis_info *vi);
void vorbis_info_clear(vorbis_info *vi);
int vorbis_info_blocksize(vorbis_info *vi,int zo);
void vorbis_comment_init(vorbis_comment *vc);
void vorbis_comment_add(vorbis_comment *vc, const char *comment);
void vorbis_comment_add_tag(vorbis_comment *vc, const char *tag, const char *contents);
char *vorbis_comment_query(vorbis_comment *vc, const char *tag, int count);
int vorbis_comment_query_count(vorbis_comment *vc, const char *tag);
void vorbis_comment_clear(vorbis_comment *vc);
int vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb);
int vorbis_block_clear(vorbis_block *vb);
void vorbis_dsp_clear(vorbis_dsp_state *v);
double vorbis_granule_time(vorbis_dsp_state *v, ogg_int64_t granulepos);
const char *vorbis_version_string(void);
int vorbis_analysis_init(vorbis_dsp_state *v,vorbis_info *vi);
int vorbis_commentheader_out(vorbis_comment *vc, ogg_packet *op);
int vorbis_analysis_headerout(vorbis_dsp_state *v,
	vorbis_comment *vc,
	ogg_packet *op,
	ogg_packet *op_comm,
	ogg_packet *op_code);
float **vorbis_analysis_buffer(vorbis_dsp_state *v,int vals);
int vorbis_analysis_wrote(vorbis_dsp_state *v,int vals);
int vorbis_analysis_blockout(vorbis_dsp_state *v,vorbis_block *vb);
int vorbis_analysis(vorbis_block *vb,ogg_packet *op);
int vorbis_bitrate_addblock(vorbis_block *vb);
int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd, ogg_packet *op);
int vorbis_synthesis_idheader(ogg_packet *op);
int vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc, ogg_packet *op);
int vorbis_synthesis_init(vorbis_dsp_state *v,vorbis_info *vi);
int vorbis_synthesis_restart(vorbis_dsp_state *v);
int vorbis_synthesis(vorbis_block *vb,ogg_packet *op);
int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op);
int vorbis_synthesis_blockin(vorbis_dsp_state *v,vorbis_block *vb);
int vorbis_synthesis_pcmout(vorbis_dsp_state *v,float ***pcm);
int vorbis_synthesis_lapout(vorbis_dsp_state *v,float ***pcm);
int vorbis_synthesis_read(vorbis_dsp_state *v,int samples);
long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op);
int vorbis_synthesis_halfrate(vorbis_info *v,int flag);
int vorbis_synthesis_halfrate_p(vorbis_info *v);
enum {
	OV_FALSE             = -1,
	OV_EOF               = -2,
	OV_HOLE              = -3,
	OV_EREAD             = -128,
	OV_EFAULT            = -129,
	OV_EIMPL             = -130,
	OV_EINVAL            = -131,
	OV_ENOTVORBIS        = -132,
	OV_EBADHEADER        = -133,
	OV_EVERSION          = -134,
	OV_ENOTAUDIO         = -135,
	OV_EBADPACKET        = -136,
	OV_EBADLINK          = -137,
	OV_ENOSEEK           = -138,
};
]]