Split secp256k1_ecmult_context_teardown() out of secp256k1_ecmult_context_clear

The 'teardown' naming is to complement the 'build' function name.  To 'build'
allocates and sets up the memory for pre_g and pre_g_128. To 'teardown' frees
the memory.

Author: isle2983

src/ecmult.h

@@ -22,6 +22,7 @@ static void secp256k1_ecmult_context_init(secp256k1_ecmult_context *ctx);
 static void secp256k1_ecmult_context_build(secp256k1_ecmult_context *ctx, const secp256k1_callback *cb);
 static void secp256k1_ecmult_context_clone(secp256k1_ecmult_context *dst,
                                            const secp256k1_ecmult_context *src, const secp256k1_callback *cb);
+static void secp256k1_ecmult_context_teardown(secp256k1_ecmult_context *ctx);
 static void secp256k1_ecmult_context_clear(secp256k1_ecmult_context *ctx);
 static int secp256k1_ecmult_context_is_built(const secp256k1_ecmult_context *ctx);
 

src/ecmult_impl.h

@@ -217,11 +217,14 @@ static int secp256k1_ecmult_context_is_built(const secp256k1_ecmult_context *ctx
     return ctx->pre_g != NULL;
 }
 
-static void secp256k1_ecmult_context_clear(secp256k1_ecmult_context *ctx) {
+static void secp256k1_ecmult_context_teardown(secp256k1_ecmult_context *ctx) {
     free(ctx->pre_g);
 #ifdef USE_ENDOMORPHISM
     free(ctx->pre_g_128);
 #endif
+}
+
+static void secp256k1_ecmult_context_clear(secp256k1_ecmult_context *ctx) {
     secp256k1_ecmult_context_init(ctx);
 }
 

src/secp256k1.c

@@ -91,6 +91,7 @@ secp256k1_context* secp256k1_context_clone(const secp256k1_context* ctx) {
 
 void secp256k1_context_destroy(secp256k1_context* ctx) {
     if (ctx != NULL) {
+        secp256k1_ecmult_context_teardown(&ctx->ecmult_ctx);
         secp256k1_ecmult_context_clear(&ctx->ecmult_ctx);
         secp256k1_ecmult_gen_context_clear(&ctx->ecmult_gen_ctx);