Import libfluidsynth into the Ardour codebase

libs/fluidsynth/src/fluid_adsr_env.h

@@ -0,0 +1,162 @@
+/* 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_ADSR_ENVELOPE_H
+#define _FLUID_ADSR_ENVELOPE_H
+
+#include "fluidsynth_priv.h"
+#include "fluid_sys.h"
+
+/*
+ * envelope data
+ */
+struct _fluid_env_data_t {
+	unsigned int count;
+	fluid_real_t coeff;
+	fluid_real_t increment;
+	fluid_real_t min;
+	fluid_real_t max;
+};
+
+/* Indices for envelope tables */
+enum fluid_voice_envelope_index_t{
+	FLUID_VOICE_ENVDELAY,
+	FLUID_VOICE_ENVATTACK,
+	FLUID_VOICE_ENVHOLD,
+	FLUID_VOICE_ENVDECAY,
+	FLUID_VOICE_ENVSUSTAIN,
+	FLUID_VOICE_ENVRELEASE,
+	FLUID_VOICE_ENVFINISHED,
+	FLUID_VOICE_ENVLAST
+};
+
+typedef enum fluid_voice_envelope_index_t fluid_adsr_env_section_t;
+
+typedef struct _fluid_adsr_env_t fluid_adsr_env_t;
+
+struct _fluid_adsr_env_t {
+	fluid_env_data_t data[FLUID_VOICE_ENVLAST];
+	unsigned int count;
+	int section;
+	fluid_real_t val;         /* the current value of the envelope */
+};
+
+/* For performance, all functions are inlined */
+
+static FLUID_INLINE void 
+fluid_adsr_env_calc(fluid_adsr_env_t* env, int is_volenv)
+{
+  fluid_env_data_t* env_data;
+  fluid_real_t x;
+
+  env_data = &env->data[env->section];
+
+  /* skip to the next section of the envelope if necessary */
+  while (env->count >= env_data->count)
+  {
+    // If we're switching envelope stages from decay to sustain, force the value to be the end value of the previous stage
+    // Hmm, should this only apply to volenv? It was so before refactoring, so keep it for now. [DH]
+    if (env->section == FLUID_VOICE_ENVDECAY && is_volenv)
+      env->val = env_data->min * env_data->coeff;
+
+    env_data = &env->data[++env->section];
+    env->count = 0;
+  }
+
+  /* calculate the envelope value and check for valid range */
+  x = env_data->coeff * env->val + env_data->increment;
+
+  if (x < env_data->min)
+  {
+    x = env_data->min;
+    env->section++;
+    env->count = 0;
+  }
+  else if (x > env_data->max)
+  {
+    x = env_data->max;
+    env->section++;
+    env->count = 0;
+  }
+
+  env->val = x;
+  env->count++;
+}
+
+/* This one cannot be inlined since it is referenced in 
+   the event queue */
+void 
+fluid_adsr_env_set_data(fluid_adsr_env_t* env,
+                        fluid_adsr_env_section_t section,
+                        unsigned int count,
+                        fluid_real_t coeff,
+                        fluid_real_t increment,
+                        fluid_real_t min,
+                        fluid_real_t max);
+
+static inline void 
+fluid_adsr_env_reset(fluid_adsr_env_t* env)
+{
+  env->count = 0;
+  env->section = 0;
+  env->val = 0.0f;
+}
+
+static inline fluid_real_t 
+fluid_adsr_env_get_val(fluid_adsr_env_t* env)
+{
+  return env->val;
+}
+
+static inline void
+fluid_adsr_env_set_val(fluid_adsr_env_t* env, fluid_real_t val)
+{
+  env->val = val;
+}
+
+static inline fluid_adsr_env_section_t
+fluid_adsr_env_get_section(fluid_adsr_env_t* env)
+{
+  return env->section;
+}
+
+static inline void 
+fluid_adsr_env_set_section(fluid_adsr_env_t* env, 
+                           fluid_adsr_env_section_t section)
+{
+  env->section = section;
+  env->count = 0;
+}
+
+/* Used for determining which voice to kill. 
+   Returns max amplitude from now, and forward in time.
+*/
+static inline fluid_real_t
+fluid_adsr_env_get_max_val(fluid_adsr_env_t* env)
+{
+  if (env->section > FLUID_VOICE_ENVATTACK){
+    return env->val * 1000;
+  } else {
+    return env->data[FLUID_VOICE_ENVATTACK].max;
+  }
+}
+
+#endif
+