1 files changed, 80 insertions, 0 deletions
diff --git a/src/sample.c b/src/sample.c
new file mode 100644
index 00000000..74a54937
--- /dev/null
+++ b/src/sample.c
@@ -0,0 +1,80 @@
+#include <string.h>
+#include <assert.h>
+
+#include "sample.h"
+
+struct sample_spec default_sample_spec = {
+    .format = SAMPLE_S16NE,
+    .rate = 44100,
+    .channels = 2
+};
+
+struct memblock *silence(struct memblock* b, struct sample_spec *spec) {
+    char c;
+    assert(b && spec);
+    memblock_assert_exclusive(b);
+
+    switch (spec->format) {
+        case SAMPLE_U8:
+            c = 127;
+            break;
+        case SAMPLE_S16LE:
+        case SAMPLE_S16BE:
+        case SAMPLE_FLOAT32:
+            c = 0;
+            break;
+        case SAMPLE_ALAW:
+        case SAMPLE_ULAW:
+            c = 80;
+            break;
+    }
+                
+    memset(b->data, c, b->length);
+    return b;
+}
+
+void add_clip(struct memchunk *target, struct memchunk *chunk, struct sample_spec *spec) {
+    int16_t *p, *d;
+    size_t i;
+    assert(target && target->memblock && chunk && chunk->memblock && spec);
+    assert(spec->format == SAMPLE_S16NE);
+    assert((target->length & 1) == 0);
+    
+    d = target->memblock->data + target->index;
+    p = chunk->memblock->data + chunk->index;
+
+    for (i = 0; i < target->length && i < chunk->length; i++) {
+        int32_t r = (int32_t) *d + (int32_t) *p;
+        if (r < -0x8000) r = 0x8000;
+        if (r > 0x7FFF) r = 0x7FFF;
+        *d = (int16_t) r;
+    }
+}
+
+size_t sample_size(struct sample_spec *spec) {
+    assert(spec);
+    size_t b;
+
+    switch (spec->format) {
+        case SAMPLE_U8:
+        case SAMPLE_ULAW:
+        case SAMPLE_ALAW:
+            b = 1;
+            break;
+        case SAMPLE_S16LE:
+        case SAMPLE_S16BE:
+            b = 2;
+            break;
+        case SAMPLE_FLOAT32:
+            b = 4;
+            break;
+    }
+
+    return b * spec->channels;
+}
+
+size_t bytes_per_second(struct sample_spec *spec) {
+    assert(spec);
+    return spec->rate*sample_size(spec);
+}
+