1 files changed, 117 insertions, 0 deletions
diff --git a/libs/fluidsynth/src/fluid_phase.h b/libs/fluidsynth/src/fluid_phase.h
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+++ b/libs/fluidsynth/src/fluid_phase.h
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+/* FluidSynth - A Software Synthesizer
+ *
+ * Copyright (C) 2003  Peter Hanappe and others.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License
+ * as published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+
+#ifndef _FLUID_PHASE_H
+#define _FLUID_PHASE_H
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+/*
+ *  phase
+ */
+
+#define FLUID_INTERP_BITS        8
+#define FLUID_INTERP_BITS_MASK   0xff000000
+#define FLUID_INTERP_BITS_SHIFT  24
+#define FLUID_INTERP_MAX         256
+
+#define FLUID_FRACT_MAX ((double)4294967296.0)
+
+/* fluid_phase_t
+* Purpose:
+* Playing pointer for voice playback
+*
+* When a sample is played back at a different pitch, the playing pointer in the
+* source sample will not advance exactly one sample per output sample.
+* This playing pointer is implemented using fluid_phase_t.
+* It is a 64 bit number. The higher 32 bits contain the 'index' (number of
+* the current sample), the lower 32 bits the fractional part.
+*/
+typedef unsigned long long fluid_phase_t;
+
+/* Purpose:
+ * Set a to b.
+ * a: fluid_phase_t
+ * b: fluid_phase_t
+ */
+#define fluid_phase_set(a,b) a=b;
+
+#define fluid_phase_set_int(a, b)    ((a) = ((unsigned long long)(b)) << 32)
+
+/* Purpose:
+ * Sets the phase a to a phase increment given in b.
+ * For example, assume b is 0.9. After setting a to it, adding a to
+ * the playing pointer will advance it by 0.9 samples. */
+#define fluid_phase_set_float(a, b) \
+  (a) = (((unsigned long long)(b)) << 32) \
+  | (uint32) (((double)(b) - (int)(b)) * (double)FLUID_FRACT_MAX)
+
+/* create a fluid_phase_t from an index and a fraction value */
+#define fluid_phase_from_index_fract(index, fract) \
+  ((((unsigned long long)(index)) << 32) + (fract))
+
+/* Purpose:
+ * Return the index and the fractional part, respectively. */
+#define fluid_phase_index(_x) \
+  ((unsigned int)((_x) >> 32))
+#define fluid_phase_fract(_x) \
+  ((uint32)((_x) & 0xFFFFFFFF))
+
+/* Get the phase index with fractional rounding */
+#define fluid_phase_index_round(_x) \
+  ((unsigned int)(((_x) + 0x80000000) >> 32))
+
+
+/* Purpose:
+ * Takes the fractional part of the argument phase and
+ * calculates the corresponding position in the interpolation table.
+ * The fractional position of the playing pointer is calculated with a quite high
+ * resolution (32 bits). It would be unpractical to keep a set of interpolation
+ * coefficients for each possible fractional part...
+ */
+#define fluid_phase_fract_to_tablerow(_x) \
+  ((unsigned int)(fluid_phase_fract(_x) & FLUID_INTERP_BITS_MASK) >> FLUID_INTERP_BITS_SHIFT)
+
+#define fluid_phase_double(_x) \
+  ((double)(fluid_phase_index(_x)) + ((double)fluid_phase_fract(_x) / FLUID_FRACT_MAX))
+
+/* Purpose:
+ * Advance a by a step of b (both are fluid_phase_t).
+ */
+#define fluid_phase_incr(a, b)  a += b
+
+/* Purpose:
+ * Subtract b from a (both are fluid_phase_t).
+ */
+#define fluid_phase_decr(a, b)  a -= b
+
+/* Purpose:
+ * Subtract b samples from a.
+ */
+#define fluid_phase_sub_int(a, b)  ((a) -= (unsigned long long)(b) << 32)
+
+/* Purpose:
+ * Creates the expression a.index++. */
+#define fluid_phase_index_plusplus(a)  (((a) += 0x100000000LL)
+
+#endif  /* _FLUID_PHASE_H */