1 files changed, 218 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/resampler.c b/lib/rbcodec/codecs/libgme/resampler.c
new file mode 100644
index 0000000000..c4f42a9794
--- /dev/null
+++ b/lib/rbcodec/codecs/libgme/resampler.c
@@ -0,0 +1,218 @@
+// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
+
+#include "resampler.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* Copyright (C) 2003-2006 Shay Green. This module 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. This
+module 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 this module; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#include "blargg_source.h"
+
+// TODO: fix this. hack since resampler holds back some output.
+unsigned const resampler_extra = 34;
+
+enum { shift = 14 };
+int const unit = 1 << shift;
+
+blargg_err_t Resampler_setup( struct Resampler* this, int fm_rate, int fm_gain, int rate, int gain )
+{
+    this->gain_ = (int)( ((1LL << gain_bits) * fm_gain * gain) / FP_ONE_GAIN );
+    this->step  = (int)( ((1LL << shift) * fm_rate) / rate + 1);
+    this->rate_ = this->step;
+    return 0;
+}
+
+blargg_err_t Resampler_reset( struct Resampler* this, int pairs )
+{
+    // expand allocations a bit
+    this->sample_buffer_size = (pairs + (pairs >> 2)) * 2;
+    Resampler_resize( this, pairs );
+    this->resampler_size = this->oversamples_per_frame + (this->oversamples_per_frame >> 2);
+
+    this->buffer_size = this->resampler_size;
+    this->pos = 0;
+    this->write_pos = 0;
+
+    Resampler_clear( this );
+    return 0;
+}
+
+void Resampler_resize( struct Resampler* this, int pairs )
+{
+    int new_sample_buf_size = pairs * 2;
+    if ( this->sample_buf_size != new_sample_buf_size )
+    {
+        if ( new_sample_buf_size > this->sample_buffer_size )
+        {
+            check(false);
+            return;
+        }
+
+        this->sample_buf_size = new_sample_buf_size;
+        this->oversamples_per_frame = (int) ((pairs * this->rate_ * 2LL) / unit) + 2;
+        Resampler_clear( this );
+    }
+}
+
+static void mix_samples( struct Resampler* this, struct Blip_Buffer* blip_buf, dsample_t out_ [] )
+{
+    int const bass = BLIP_READER_BASS( *blip_buf );
+    BLIP_READER_BEGIN( sn, *blip_buf );
+
+    int count = this->sample_buf_size >> 1;
+    BLIP_READER_ADJ_( sn, count );
+
+    typedef dsample_t stereo_dsample_t [2];
+    stereo_dsample_t* BLARGG_RESTRICT out = (stereo_dsample_t*) out_ + count;
+    stereo_dsample_t const* BLARGG_RESTRICT in =
+        (stereo_dsample_t const*) this->sample_buf + count;
+    int offset = -count;
+    int const gain = this->gain_;
+    do
+    {
+        int s = BLIP_READER_READ_RAW( sn ) >> (blip_sample_bits - 16);
+        BLIP_READER_NEXT_IDX_( sn, bass, offset );
+
+        int l = (in [offset] [0] * gain >> gain_bits) + s;
+        int r = (in [offset] [1] * gain >> gain_bits) + s;
+
+        BLIP_CLAMP( l, l );
+        out [offset] [0] = (blip_sample_t) l;
+
+        BLIP_CLAMP( r, r );
+        out [offset] [1] = (blip_sample_t) r;
+    }
+    while ( ++offset );
+
+    BLIP_READER_END( sn, *blip_buf );
+}
+
+static dsample_t const* resample_( struct Resampler* this, dsample_t** out_,
+        dsample_t const* out_end, dsample_t const in [], int in_size )
+{
+    in_size -= write_offset;
+    if ( in_size > 0 )
+    {
+        dsample_t* BLARGG_RESTRICT out = *out_;
+        dsample_t const* const in_end = in + in_size;
+
+        int const step = this->step;
+        int       pos  = this->pos;
+
+        // TODO: IIR filter, then linear resample
+        // TODO: detect skipped sample, allowing merging of IIR and resample?
+
+        do
+        {
+            #define INTERP( i, out )\
+                out = (in [0 + i] * (unit - pos) + ((in [2 + i] + in [4 + i] + in [6 + i]) << shift) +\
+                in [8 + i] * pos) >> (shift + 2);
+
+            int out_0;
+            INTERP( 0,                  out_0 )
+            INTERP( 1, out [0] = out_0; out [1] )
+            out += stereo;
+
+            pos += step;
+            in += ((unsigned) pos >> shift) * stereo;
+            pos &= unit - 1;
+        }
+        while ( in < in_end && out < out_end );
+
+        this->pos = pos;
+        *out_ = out;
+    }
+    return in;
+}
+
+static inline int resample_wrapper( struct Resampler* this, dsample_t out [], int* out_size,
+        dsample_t const in [], int in_size )
+{
+    assert( Resampler_rate( this ) );
+
+    dsample_t* out_ = out;
+    int result = resample_( this, &out_, out + *out_size, in, in_size ) - in;
+    assert( out_ <= out + *out_size );
+    assert( result <= in_size );
+
+    *out_size = out_ - out;
+    return result;
+}
+
+static int skip_input( struct Resampler* this, int count )
+{
+    this->write_pos -= count;
+    if ( this->write_pos < 0 ) // occurs when downsampling
+    {
+        count += this->write_pos;
+        this->write_pos = 0;
+    }
+    memmove( this->buf, &this->buf [count], this->write_pos * sizeof this->buf [0] );
+    return count;
+}
+
+static void play_frame_( struct Resampler* this, struct Blip_Buffer* blip_buf, dsample_t* out )
+{
+    int pair_count = this->sample_buf_size >> 1;
+    blip_time_t blip_time = Blip_count_clocks( blip_buf, pair_count );
+    int sample_count = this->oversamples_per_frame - this->write_pos + resampler_extra;
+
+    int new_count = this->callback( this->callback_data, blip_time, sample_count, &this->buf [this->write_pos] );
+    assert( new_count < this->resampler_size );
+
+    Blip_end_frame( blip_buf, blip_time );
+    assert( Blip_samples_avail( blip_buf ) == pair_count );
+
+    this->write_pos += new_count;
+    assert( (unsigned) this->write_pos <= this->buffer_size );
+
+    int count = this->sample_buf_size;
+    if ( count )
+        skip_input( this, resample_wrapper( this, this->sample_buf, &count, this->buf, this->write_pos ) );
+    assert( count == this->sample_buf_size );
+
+    mix_samples( this, blip_buf, out );
+    Blip_remove_samples( blip_buf, pair_count );
+}
+
+void Resampler_play( struct Resampler* this, int count, dsample_t* out, struct Blip_Buffer* blip_buf )
+{
+    // empty extra buffer
+    int remain = this->sample_buf_size - this->buf_pos;
+    if ( remain )
+    {
+        if ( remain > count )
+            remain = count;
+        count -= remain;
+        memcpy( out, &this->sample_buf [this->buf_pos], remain * sizeof *out );
+        out += remain;
+        this->buf_pos += remain;
+    }
+
+    // entire frames
+    while ( count >= this->sample_buf_size )
+    {
+        play_frame_( this, blip_buf, out );
+        out += this->sample_buf_size;
+        count -= this->sample_buf_size;
+    }
+
+    // extra
+    if ( count )
+    {
+        play_frame_( this, blip_buf, this->sample_buf );
+        this->buf_pos = count;
+        memcpy( out, this->sample_buf, count * sizeof *out );
+        out += count;
+    }
+}