transfer: implement and use 1D interpolation

Stop abusing "2D of y size 1" for this.

1 files changed, 23 insertions, 3 deletions

diff --git a/transfer_interp_template.c b/transfer_interp_template.c
index e7ff14a..7bfc89e 100644
--- a/transfer_interp_template.c
+++ b/transfer_interp_template.c
@@ -27,9 +27,9 @@
 #define FUNC(name) FUNC2(name, CONT, STENCIL)
 
 static void
-FUNC(interp_transfer_line)(double *dst, ptrdiff_t dst_len,
-                           const double *src, ptrdiff_t src_stride,
-                           const ptrdiff_t *idx_x, const double *fact_x, const double *fact_y
+FUNC(interp2d_transfer_line)(double *dst, ptrdiff_t dst_len,
+                             const double *src, ptrdiff_t src_stride,
+                             const ptrdiff_t *idx_x, const double *fact_x, const double *fact_y
 #if !CONTIGUOUS
                            , ptrdiff_t dst_stride0, ptrdiff_t src_stride0
 # define SSTRIDE1 src_stride0
@@ -56,6 +56,26 @@ FUNC(interp_transfer_line)(double *dst, ptrdiff_t dst_len,
     }
 }
 
+static void
+FUNC(interp1d_transfer_line)(double *dst, ptrdiff_t dst_len,
+                             const double *src, const ptrdiff_t *idx_x, const double *fact_x
+#if !CONTIGUOUS
+                           , ptrdiff_t dst_stride0, ptrdiff_t src_stride0
+#endif
+                           )
+{
+    for (size_t x = 0; x < dst_len; x++) {
+        const double *src_data = src + SSTRIDE1 * idx_x[x];
+
+        double val = 0.0;
+
+        for (ptrdiff_t idx = 0; idx < STENCIL; idx++)
+            val += src_data[idx * SSTRIDE1] * fact_x[STENCIL * x + idx];
+
+        dst[x * DSTRIDE1] = val;
+    }
+}
+
 #undef SSTRIDE1
 #undef DSTRIDE1
 #undef CONT