1 files changed, 51 insertions, 2 deletions

diff --git a/media/libaom/src/aom_dsp/bitreader_buffer.c b/media/libaom/src/aom_dsp/bitreader_buffer.c
index b532117849..d79feea6a3 100644
--- a/media/libaom/src/aom_dsp/bitreader_buffer.c
+++ b/media/libaom/src/aom_dsp/bitreader_buffer.c
@@ -14,6 +14,8 @@
 #include "config/aom_config.h"
 
 #include "aom_dsp/bitreader_buffer.h"
+#include "aom_dsp/recenter.h"
+#include "aom_ports/bitops.h"
 
 size_t aom_rb_bytes_read(const struct aom_read_bit_buffer *rb) {
   return (rb->bit_offset + 7) >> 3;
@@ -58,10 +60,57 @@ int aom_rb_read_inv_signed_literal(struct aom_read_bit_buffer *rb, int bits) {
 
 uint32_t aom_rb_read_uvlc(struct aom_read_bit_buffer *rb) {
   int leading_zeros = 0;
-  while (!aom_rb_read_bit(rb)) ++leading_zeros;
+  while (leading_zeros < 32 && !aom_rb_read_bit(rb)) ++leading_zeros;
   // Maximum 32 bits.
-  if (leading_zeros >= 32) return UINT32_MAX;
+  if (leading_zeros == 32) return UINT32_MAX;
   const uint32_t base = (1u << leading_zeros) - 1;
   const uint32_t value = aom_rb_read_literal(rb, leading_zeros);
   return base + value;
 }
+
+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);
+}
+
+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;
+}
+
+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;
+}