ref: d28e6a3a2e81d09df3ab7d078e9b77d1b8cbee46
parent: 222bf2495f26d0445b856b469c11537a926917f2
author: Henrik Gramner <[email protected]>
date: Fri Feb 15 08:05:21 EST 2019
Make msac_decode_symbol() static It's only used by msac_decode_symbol_adapt() in the same file.
--- a/src/msac.c
+++ b/src/msac.c
@@ -68,30 +68,6 @@
ctx_refill(s);
}
-/* Decodes a symbol given an inverse cumulative distribution function (CDF)
- * table in Q15. */
-unsigned msac_decode_symbol(MsacContext *const s, const uint16_t *const cdf,
- const unsigned n_symbols)
-{- ec_win u, v = s->rng, r = s->rng >> 8;
- const ec_win c = s->dif >> (EC_WIN_SIZE - 16);
- unsigned ret = 0;
-
- assert(!cdf[n_symbols - 1]);
-
- do {- u = v;
- v = r * (cdf[ret++] >> EC_PROB_SHIFT);
- v >>= 7 - EC_PROB_SHIFT;
- v += EC_MIN_PROB * (n_symbols - ret);
- } while (c < v);
-
- assert(u <= s->rng);
-
- ctx_norm(s, s->dif - (v << (EC_WIN_SIZE - 16)), (unsigned) (u - v));
- return ret - 1;
-}
-
unsigned msac_decode_bool_equi(MsacContext *const s) {ec_win v, vw, dif = s->dif;
uint16_t r = s->rng;
@@ -157,6 +133,30 @@
return v < m ? v : (v << 1) - m + msac_decode_bool_equi(c);
}
+/* Decodes a symbol given an inverse cumulative distribution function (CDF)
+ * table in Q15. */
+static unsigned decode_symbol(MsacContext *const s, const uint16_t *const cdf,
+ const unsigned n_symbols)
+{+ ec_win u, v = s->rng, r = s->rng >> 8;
+ const ec_win c = s->dif >> (EC_WIN_SIZE - 16);
+ unsigned ret = 0;
+
+ assert(!cdf[n_symbols - 1]);
+
+ do {+ u = v;
+ v = r * (cdf[ret++] >> EC_PROB_SHIFT);
+ v >>= 7 - EC_PROB_SHIFT;
+ v += EC_MIN_PROB * (n_symbols - ret);
+ } while (c < v);
+
+ assert(u <= s->rng);
+
+ ctx_norm(s, s->dif - (v << (EC_WIN_SIZE - 16)), (unsigned) (u - v));
+ return ret - 1;
+}
+
static void update_cdf(uint16_t *const cdf, const unsigned val,
const unsigned n_symbols)
{@@ -173,7 +173,7 @@
unsigned msac_decode_symbol_adapt(MsacContext *const c,
uint16_t *const cdf, const unsigned n_symbols)
{- const unsigned val = msac_decode_symbol(c, cdf, n_symbols);
+ const unsigned val = decode_symbol(c, cdf, n_symbols);
if(c->allow_update_cdf)
update_cdf(cdf, val, n_symbols);
return val;
--- a/src/msac.h
+++ b/src/msac.h
@@ -44,8 +44,6 @@
} MsacContext;
void msac_init(MsacContext *c, const uint8_t *data, size_t sz, int disable_cdf_update_flag);
-unsigned msac_decode_symbol(MsacContext *s, const uint16_t *cdf,
- const unsigned n_symbols);
unsigned msac_decode_symbol_adapt(MsacContext *s, uint16_t *cdf,
const unsigned n_symbols);
unsigned msac_decode_bool_equi(MsacContext *const s);