shithub: dav1d

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Match style for update_cdf and remove nsymbs2speed

We can simplify as cdfs have at least 2 symbols.

--- a/src/msac.c

+++ b/src/msac.c

@@ -140,24 +140,17 @@

     return v < m ? v : (v << 1) - m + msac_decode_bool(c, EC_BOOL_EPROB);

 }

-void update_cdf(uint16_t *cdf, unsigned val, unsigned nsymbs) {

-    int rate;

+void msac_update_cdf(uint16_t *const cdf, const unsigned val,

+                     const unsigned n_symbols)

+{

+    const int rate = 4 + (cdf[n_symbols] > 15) + (cdf[n_symbols] > 31) +

+                     (n_symbols > 3);

     unsigned i;

-

-    static const int nsymbs2speed[17] = {

-        0, 0, 1, 1, 2, 2, 2, 2, 2,

-        2, 2, 2, 2, 2, 2, 2, 2

-    };

-    assert(nsymbs < 17);

-    rate = 3 + (cdf[nsymbs] > 15) + (cdf[nsymbs] > 31) + nsymbs2speed[nsymbs];

-

     for (i = 0; i < val; ++i)

         cdf[i] += (32768 - cdf[i]) >> rate;

-

-    for (i = val; i < nsymbs - 1; i++)

+    for (i = val; i < n_symbols - 1; i++)

         cdf[i] -= cdf[i] >> rate;

-

-    cdf[nsymbs] += (cdf[nsymbs] < 32);

+    cdf[n_symbols] += (cdf[n_symbols] < 32);

 }

 void msac_init(MsacContext *const s, const uint8_t *const data,

--- a/src/msac.h

+++ b/src/msac.h

@@ -52,7 +52,7 @@

 unsigned msac_decode_bools(MsacContext *c, unsigned l);

 int msac_decode_subexp(MsacContext *c, int ref, int n, unsigned k);

 int msac_decode_uniform(MsacContext *c, unsigned n);

-void update_cdf(uint16_t *cdf, unsigned val, unsigned nsymbs);

+void msac_update_cdf(uint16_t *cdf, unsigned val, unsigned n_symbols);

 static inline unsigned msac_decode_symbol_adapt(MsacContext *const c,

                                                 uint16_t *const cdf,

@@ -59,7 +59,7 @@

                                                 const unsigned n_symbols)

 {

     const unsigned val = msac_decode_symbol(c, cdf, n_symbols);

-    update_cdf(cdf, val, n_symbols);

+    msac_update_cdf(cdf, val, n_symbols);

     return val;

 }

@@ -68,7 +68,7 @@

 {

     const unsigned bit = msac_decode_bool(c, *cdf >> EC_PROB_SHIFT);

     uint16_t bak_cdf[3] = { cdf[0], 0, cdf[1] };

-    update_cdf(bak_cdf, bit, 2);

+    msac_update_cdf(bak_cdf, bit, 2);

     cdf[0] = bak_cdf[0];

     cdf[1] = bak_cdf[2];

     return bit;