diff audioDB-internals.h @ 427:adaa6a688a04 api-inversion

Move sequence_foo() functions out of audioDB:: namespace...

... and into the internals header, mostly to get them out of the way.
That means they have to be inline, which is probably suboptimal but will
do for now.

--- a/audioDB-internals.h	Wed Dec 24 10:55:20 2008 +0000
+++ b/audioDB-internals.h	Wed Dec 24 10:55:24 2008 +0000
@@ -119,3 +119,53 @@
     d += dim;
   }
 }
+
+// This is a common pattern in sequence queries: what we are doing is
+// taking a window of length seqlen over a buffer of length length,
+// and placing the sum of the elements in that window in the first
+// element of the window: thus replacing all but the last seqlen
+// elements in the buffer with the corresponding windowed sum.
+static inline void audiodb_sequence_sum(double *buffer, int length, int seqlen) {
+  double tmp1, tmp2, *ps;
+  int j, w;
+
+  tmp1 = *buffer;
+  j = 1;
+  w = seqlen - 1;
+  while(w--) {
+    *buffer += buffer[j++];
+  }
+  ps = buffer + 1;
+  w = length - seqlen; // +1 - 1
+  while(w--) {
+    tmp2 = *ps;
+    if(isfinite(tmp1)) {
+      *ps = *(ps - 1) - tmp1 + *(ps + seqlen - 1);
+    } else {
+      for(int i = 1; i < seqlen; i++) {
+        *ps += *(ps + i);
+      }
+    }
+    tmp1 = tmp2;
+    ps++;
+  }
+}
+
+// In contrast to audiodb_sequence_sum() above,
+// audiodb_sequence_sqrt() and audiodb_sequence_average() below are
+// simple mappers across the sequence.
+static inline void audiodb_sequence_sqrt(double *buffer, int length, int seqlen) {
+  int w = length - seqlen + 1;
+  while(w--) {
+    *buffer = sqrt(*buffer);
+    buffer++;
+  }
+}
+
+static inline void audiodb_sequence_average(double *buffer, int length, int seqlen) {
+  int w = length - seqlen + 1;
+  while(w--) {
+    *buffer /= seqlen;
+    buffer++;
+  }
+}