ans: Remove some dead code.

This was part of the old ans zero token handling. It has been replaced
by the new ec_multisymbol zero token handling.

Change-Id: I9c1fcb42ac0d214178cf4fbf8755ad68dcbbc11f

aom_dsp/ans.c

-/*
- * Copyright (c) 2016, 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 <assert.h>
-#include "./aom_config.h"
-#include "aom/aom_integer.h"
-#include "aom_dsp/ans.h"
-#include "aom_dsp/prob.h"
-
-static int find_largest(const aom_cdf_prob *const pdf_tab, int num_syms) {
-  int largest_idx = -1;
-  int largest_p = -1;
-  int i;
-  for (i = 0; i < num_syms; ++i) {
-    int p = pdf_tab[i];
-    if (p > largest_p) {
-      largest_p = p;
-      largest_idx = i;
-    }
-  }
-  return largest_idx;
-}
-
-void aom_rans_merge_prob8_pdf(aom_cdf_prob *const out_pdf,
-                              const AnsP8 node_prob,
-                              const aom_cdf_prob *const src_pdf, int in_syms) {
-  int i;
-  int adjustment = RANS_PRECISION;
-  const int round_fact = ANS_P8_PRECISION >> 1;
-  const AnsP8 p1 = ANS_P8_PRECISION - node_prob;
-  const int out_syms = in_syms + 1;
-  assert(src_pdf != out_pdf);
-
-  out_pdf[0] = node_prob << (RANS_PROB_BITS - ANS_P8_SHIFT);
-  adjustment -= out_pdf[0];
-  for (i = 0; i < in_syms; ++i) {
-    int p = (p1 * src_pdf[i] + round_fact) >> ANS_P8_SHIFT;
-    p = AOMMIN(p, (int)RANS_PRECISION - in_syms);
-    p = AOMMAX(p, 1);
-    out_pdf[i + 1] = p;
-    adjustment -= p;
-  }
-
-  // Adjust probabilities so they sum to the total probability
-  if (adjustment > 0) {
-    i = find_largest(out_pdf, out_syms);
-    out_pdf[i] += adjustment;
-  } else {
-    while (adjustment < 0) {
-      i = find_largest(out_pdf, out_syms);
-      --out_pdf[i];
-      assert(out_pdf[i] > 0);
-      adjustment++;
-    }
-  }
-}

aom_dsp/ans.h

@@ -39,9 +39,6 @@ typedef uint8_t AnsP8;
 #define IO_BASE 256
 // Range I = { L_BASE, L_BASE + 1, ..., L_BASE * IO_BASE - 1 }
 
-void aom_rans_merge_prob8_pdf(aom_cdf_prob *const out_pdf,
-                              const AnsP8 node_prob,
-                              const aom_cdf_prob *const src_pdf, int in_syms);
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus

aom_dsp/aom_dsp.mk

@@ -21,7 +21,6 @@ DSP_SRCS-$(ARCH_X86)$(ARCH_X86_64)   += x86/synonyms.h
 DSP_SRCS-yes += prob.h
 DSP_SRCS-yes += prob.c
 DSP_SRCS-$(CONFIG_ANS) += ans.h
-DSP_SRCS-$(CONFIG_ANS) += ans.c
 
 ifeq ($(CONFIG_ENCODERS),yes)
 ifeq ($(CONFIG_ANS),yes)