1 files changed, 123 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/binary_codes_reader.c b/third_party/aom/aom_dsp/binary_codes_reader.c
new file mode 100644
index 0000000000..01088010a1
--- /dev/null
+++ b/third_party/aom/aom_dsp/binary_codes_reader.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2017, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include "aom_dsp/binary_codes_reader.h"
+
+#include "av1/common/common.h"
+
+// Inverse recenters a non-negative literal v around a reference r
+static uint16_t inv_recenter_nonneg(uint16_t r, uint16_t v) {
+  if (v > (r << 1))
+    return v;
+  else if ((v & 1) == 0)
+    return (v >> 1) + r;
+  else
+    return r - ((v + 1) >> 1);
+}
+
+// Inverse recenters a non-negative literal v in [0, n-1] around a
+// reference r also in [0, n-1]
+static uint16_t inv_recenter_finite_nonneg(uint16_t n, uint16_t r, uint16_t v) {
+  if ((r << 1) <= n) {
+    return inv_recenter_nonneg(r, v);
+  } else {
+    return n - 1 - inv_recenter_nonneg(n - 1 - r, v);
+  }
+}
+
+uint16_t aom_read_primitive_quniform_(aom_reader *r,
+                                      uint16_t n ACCT_STR_PARAM) {
+  if (n <= 1) return 0;
+  const int l = get_msb(n) + 1;
+  const int m = (1 << l) - n;
+  const int v = aom_read_literal(r, l - 1, ACCT_STR_NAME);
+  return v < m ? v : (v << 1) - m + aom_read_bit(r, ACCT_STR_NAME);
+}
+
+static uint16_t aom_rb_read_primitive_quniform(struct aom_read_bit_buffer *rb,
+                                               uint16_t n) {
+  if (n <= 1) return 0;
+  const int l = get_msb(n) + 1;
+  const int m = (1 << l) - n;
+  const int v = aom_rb_read_literal(rb, l - 1);
+  return v < m ? v : (v << 1) - m + aom_rb_read_bit(rb);
+}
+
+// Decode finite subexponential code that for a symbol v in [0, n-1] with
+// parameter k
+uint16_t aom_read_primitive_subexpfin_(aom_reader *r, uint16_t n,
+                                       uint16_t k ACCT_STR_PARAM) {
+  int i = 0;
+  int mk = 0;
+
+  while (1) {
+    int b = (i ? k + i - 1 : k);
+    int a = (1 << b);
+
+    if (n <= mk + 3 * a) {
+      return aom_read_primitive_quniform(r, n - mk, ACCT_STR_NAME) + mk;
+    }
+
+    if (!aom_read_bit(r, ACCT_STR_NAME)) {
+      return aom_read_literal(r, b, ACCT_STR_NAME) + mk;
+    }
+
+    i = i + 1;
+    mk += a;
+  }
+
+  assert(0);
+  return 0;
+}
+
+static uint16_t aom_rb_read_primitive_subexpfin(struct aom_read_bit_buffer *rb,
+                                                uint16_t n, uint16_t k) {
+  int i = 0;
+  int mk = 0;
+
+  while (1) {
+    int b = (i ? k + i - 1 : k);
+    int a = (1 << b);
+
+    if (n <= mk + 3 * a) {
+      return aom_rb_read_primitive_quniform(rb, n - mk) + mk;
+    }
+
+    if (!aom_rb_read_bit(rb)) {
+      return aom_rb_read_literal(rb, b) + mk;
+    }
+
+    i = i + 1;
+    mk += a;
+  }
+
+  assert(0);
+  return 0;
+}
+
+uint16_t aom_read_primitive_refsubexpfin_(aom_reader *r, uint16_t n, uint16_t k,
+                                          uint16_t ref ACCT_STR_PARAM) {
+  return inv_recenter_finite_nonneg(
+      n, ref, aom_read_primitive_subexpfin(r, n, k, ACCT_STR_NAME));
+}
+
+static uint16_t aom_rb_read_primitive_refsubexpfin(
+    struct aom_read_bit_buffer *rb, uint16_t n, uint16_t k, uint16_t ref) {
+  return inv_recenter_finite_nonneg(n, ref,
+                                    aom_rb_read_primitive_subexpfin(rb, n, k));
+}
+
+int16_t aom_rb_read_signed_primitive_refsubexpfin(
+    struct aom_read_bit_buffer *rb, uint16_t n, uint16_t k, int16_t ref) {
+  ref += n - 1;
+  const uint16_t scaled_n = (n << 1) - 1;
+  return aom_rb_read_primitive_refsubexpfin(rb, scaled_n, k, ref) - n + 1;
+}