1 files changed, 144 insertions, 0 deletions
diff --git a/polyp/sample-util.c b/polyp/sample-util.c
new file mode 100644
index 00000000..d608ce1b
--- /dev/null
+++ b/polyp/sample-util.c
@@ -0,0 +1,144 @@
+/* $Id$ */
+
+/***
+  This file is part of polypaudio.
+ 
+  polypaudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 2 of the License,
+  or (at your option) any later version.
+ 
+  polypaudio 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
+  General Public License for more details.
+ 
+  You should have received a copy of the GNU General Public License
+  along with polypaudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "sample-util.h"
+
+struct pa_memblock *pa_silence_memblock(struct pa_memblock* b, const struct pa_sample_spec *spec) {
+    assert(b && b->data && spec);
+    pa_silence_memory(b->data, b->length, spec);
+    return b;
+}
+
+void pa_silence_memchunk(struct pa_memchunk *c, const struct pa_sample_spec *spec) {
+    assert(c && c->memblock && c->memblock->data && spec && c->length);
+    pa_silence_memory(c->memblock->data+c->index, c->length, spec);
+}
+
+void pa_silence_memory(void *p, size_t length, const struct pa_sample_spec *spec) {
+    char c = 0;
+    assert(p && length && spec);
+
+    switch (spec->format) {
+        case PA_SAMPLE_U8:
+            c = 127;
+            break;
+        case PA_SAMPLE_S16LE:
+        case PA_SAMPLE_S16BE:
+        case PA_SAMPLE_FLOAT32:
+            c = 0;
+            break;
+        case PA_SAMPLE_ALAW:
+        case PA_SAMPLE_ULAW:
+            c = 80;
+            break;
+        default:
+            assert(0);
+    }
+                
+    memset(p, c, length);
+}
+
+size_t pa_mix(struct pa_mix_info channels[], unsigned nchannels, void *data, size_t length, const struct pa_sample_spec *spec, uint32_t volume) {
+    unsigned c, d;
+    assert(channels && data && length && spec);
+    assert(spec->format == PA_SAMPLE_S16NE);
+
+    for (d = 0;; d += sizeof(int16_t)) {
+        int32_t sum = 0;
+
+        if (d >= length)
+            return d;
+        
+        for (c = 0; c < nchannels; c++) {
+            int32_t v;
+            uint32_t volume = channels[c].volume;
+            
+            if (d >= channels[c].chunk.length)
+                return d;
+
+            if (volume == PA_VOLUME_MUTE)
+                v = 0;
+            else {
+                v = *((int16_t*) (channels[c].chunk.memblock->data + channels[c].chunk.index + d));
+
+                if (volume != PA_VOLUME_NORM)
+                    v = (int32_t) ((float)v*volume/PA_VOLUME_NORM);
+            }
+
+            sum += v;
+        }
+
+        if (volume == PA_VOLUME_MUTE)
+            sum = 0;
+        else if (volume != PA_VOLUME_NORM)
+            sum = (int32_t) ((float) sum*volume/PA_VOLUME_NORM);
+        
+        if (sum < -0x8000) sum = -0x8000;
+        if (sum > 0x7FFF) sum = 0x7FFF;
+        
+        *((int16_t*) data) = sum;
+        data += sizeof(int16_t);
+    }
+}
+
+
+void pa_volume_memchunk(struct pa_memchunk*c, const struct pa_sample_spec *spec, uint32_t volume) {
+    int16_t *d;
+    size_t n;
+    assert(c && spec && (c->length % pa_sample_size(spec) == 0));
+    assert(spec->format == PA_SAMPLE_S16NE);
+
+    if (volume == PA_VOLUME_NORM)
+        return;
+
+    if (volume == PA_VOLUME_MUTE) {
+        pa_silence_memchunk(c, spec);
+        return;
+    }
+
+    for (d = (c->memblock->data+c->index), n = c->length/sizeof(int16_t); n > 0; d++, n--) {
+        int32_t t = (int32_t)(*d);
+
+        t *= volume;
+        t /= PA_VOLUME_NORM;
+
+        if (t < -0x8000) t = -0x8000;
+        if (t > 0x7FFF) t = 0x7FFF;
+        
+        *d = (int16_t) t;
+    }
+}
+
+uint32_t pa_volume_multiply(uint32_t a, uint32_t b) {
+    uint64_t p = a;
+    p *= b;
+    p /= PA_VOLUME_NORM;
+
+    return (uint32_t) p;
+}