C89 nits and dead code removal.

src/ecdsa.h

@@ -10,9 +10,6 @@
 #include "scalar.h"
 #include "group.h"
 
-static void secp256k1_ecsda_start(void);
-static void secp256k1_ecdsa_stop(void);
-
 typedef struct {
     secp256k1_scalar_t r, s;
 } secp256k1_ecdsa_sig_t;
@@ -22,6 +19,5 @@ static int secp256k1_ecdsa_sig_serialize(unsigned char *sig, int *size, const se
 static int secp256k1_ecdsa_sig_verify(const secp256k1_ecdsa_sig_t *sig, const secp256k1_ge_t *pubkey, const secp256k1_scalar_t *message);
 static int secp256k1_ecdsa_sig_sign(secp256k1_ecdsa_sig_t *sig, const secp256k1_scalar_t *seckey, const secp256k1_scalar_t *message, const secp256k1_scalar_t *nonce, int *recid);
 static int secp256k1_ecdsa_sig_recover(const secp256k1_ecdsa_sig_t *sig, secp256k1_ge_t *pubkey, const secp256k1_scalar_t *message, int recid);
-static void secp256k1_ecdsa_sig_set_rs(secp256k1_ecdsa_sig_t *sig, const secp256k1_scalar_t *r, const secp256k1_scalar_t *s);
 
 #endif

src/ecdsa_impl.h

@@ -98,32 +98,33 @@ static int secp256k1_ecdsa_sig_verify(const secp256k1_ecdsa_sig_t *sig, const se
     secp256k1_fe_t xr;
     secp256k1_fe_set_b32(&xr, c);
 
-    // We now have the recomputed R point in pr, and its claimed x coordinate (modulo n)
-    // in xr. Naively, we would extract the x coordinate from pr (requiring a inversion modulo p),
-    // compute the remainder modulo n, and compare it to xr. However:
-    //
-    //       xr == X(pr) mod n
-    //   <=> exists h. (xr + h * n < p && xr + h * n == X(pr))
-    //   [Since 2 * n > p, h can only be 0 or 1]
-    //   <=> (xr == X(pr)) || (xr + n < p && xr + n == X(pr))
-    //   [In Jacobian coordinates, X(pr) is pr.x / pr.z^2 mod p]
-    //   <=> (xr == pr.x / pr.z^2 mod p) || (xr + n < p && xr + n == pr.x / pr.z^2 mod p)
-    //   [Multiplying both sides of the equations by pr.z^2 mod p]
-    //   <=> (xr * pr.z^2 mod p == pr.x) || (xr + n < p && (xr + n) * pr.z^2 mod p == pr.x)
-    //
-    // Thus, we can avoid the inversion, but we have to check both cases separately.
-    // secp256k1_gej_eq_x implements the (xr * pr.z^2 mod p == pr.x) test.
+    /** We now have the recomputed R point in pr, and its claimed x coordinate (modulo n)
+     *  in xr. Naively, we would extract the x coordinate from pr (requiring a inversion modulo p),
+     *  compute the remainder modulo n, and compare it to xr. However:
+     *
+     *        xr == X(pr) mod n
+     *    <=> exists h. (xr + h * n < p && xr + h * n == X(pr))
+     *    [Since 2 * n > p, h can only be 0 or 1]
+     *    <=> (xr == X(pr)) || (xr + n < p && xr + n == X(pr))
+     *    [In Jacobian coordinates, X(pr) is pr.x / pr.z^2 mod p]
+     *    <=> (xr == pr.x / pr.z^2 mod p) || (xr + n < p && xr + n == pr.x / pr.z^2 mod p)
+     *    [Multiplying both sides of the equations by pr.z^2 mod p]
+     *    <=> (xr * pr.z^2 mod p == pr.x) || (xr + n < p && (xr + n) * pr.z^2 mod p == pr.x)
+     *
+     *  Thus, we can avoid the inversion, but we have to check both cases separately.
+     *  secp256k1_gej_eq_x implements the (xr * pr.z^2 mod p == pr.x) test.
+     */
     if (secp256k1_gej_eq_x_var(&xr, &pr)) {
-        // xr.x == xr * xr.z^2 mod p, so the signature is valid.
+        /* xr.x == xr * xr.z^2 mod p, so the signature is valid. */
         return 1;
     }
     if (secp256k1_fe_cmp_var(&xr, &secp256k1_ecdsa_const_p_minus_order) >= 0) {
-        // xr + p >= n, so we can skip testing the second case.
+        /* xr + p >= n, so we can skip testing the second case. */
         return 0;
     }
     secp256k1_fe_add(&xr, &secp256k1_ecdsa_const_order_as_fe);
     if (secp256k1_gej_eq_x_var(&xr, &pr)) {
-        // (xr + n) * pr.z^2 mod p == pr.x, so the signature is valid.
+        /* (xr + n) * pr.z^2 mod p == pr.x, so the signature is valid. */
         return 1;
     }
     return 0;
@@ -195,9 +196,4 @@ static int secp256k1_ecdsa_sig_sign(secp256k1_ecdsa_sig_t *sig, const secp256k1_
     return 1;
 }
 
-static void secp256k1_ecdsa_sig_set_rs(secp256k1_ecdsa_sig_t *sig, const secp256k1_scalar_t *r, const secp256k1_scalar_t *s) {
-    sig->r = *r;
-    sig->s = *s;
-}
-
 #endif

src/field.h

@@ -102,7 +102,7 @@ static void secp256k1_fe_inv_var(secp256k1_fe_t *r, const secp256k1_fe_t *a);
 /** Calculate the (modular) inverses of a batch of field elements. Requires the inputs' magnitudes to be
  *  at most 8. The output magnitudes are 1 (but not guaranteed to be normalized). The inputs and
  *  outputs must not overlap in memory. */
-static void secp256k1_fe_inv_all_var(size_t len, secp256k1_fe_t r[len], const secp256k1_fe_t a[len]);
+static void secp256k1_fe_inv_all_var(size_t len, secp256k1_fe_t *r, const secp256k1_fe_t *a);
 
 /** Convert a field element to a hexadecimal string. */
 static void secp256k1_fe_get_hex(char *r, int *rlen, const secp256k1_fe_t *a);

src/field_impl.h

@@ -40,7 +40,7 @@ static void secp256k1_fe_get_hex(char *r, int *rlen, const secp256k1_fe_t *a) {
 }
 
 static int secp256k1_fe_set_hex(secp256k1_fe_t *r, const char *a, int alen) {
-    unsigned char tmp[32] = {};
+    unsigned char tmp[32] = {0};
     static const int cvt[256] = {0, 0, 0, 0, 0, 0, 0,0,0,0,0,0,0,0,0,0,
                                  0, 0, 0, 0, 0, 0, 0,0,0,0,0,0,0,0,0,0,
                                  0, 0, 0, 0, 0, 0, 0,0,0,0,0,0,0,0,0,0,
@@ -227,7 +227,7 @@ static void secp256k1_fe_inv_var(secp256k1_fe_t *r, const secp256k1_fe_t *a) {
 #endif
 }
 
-static void secp256k1_fe_inv_all_var(size_t len, secp256k1_fe_t r[len], const secp256k1_fe_t a[len]) {
+static void secp256k1_fe_inv_all_var(size_t len, secp256k1_fe_t *r, const secp256k1_fe_t *a) {
     if (len < 1)
         return;
 

src/group.h

@@ -50,7 +50,7 @@ static void secp256k1_ge_get_hex(char *r, int *rlen, const secp256k1_ge_t *a);
 static void secp256k1_ge_set_gej(secp256k1_ge_t *r, secp256k1_gej_t *a);
 
 /** Set a batch of group elements equal to the inputs given in jacobian coordinates */
-static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t r[len], const secp256k1_gej_t a[len]);
+static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t *r, const secp256k1_gej_t *a);
 
 
 /** Set a group element (jacobian) equal to the point at infinity. */

src/group_impl.h

@@ -93,7 +93,7 @@ static void secp256k1_ge_set_gej_var(secp256k1_ge_t *r, secp256k1_gej_t *a) {
     r->y = a->y;
 }
 
-static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t r[len], const secp256k1_gej_t a[len]) {
+static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t *r, const secp256k1_gej_t *a) {
     size_t count = 0;
     secp256k1_fe_t *az = checked_malloc(sizeof(secp256k1_fe_t) * len);
     for (size_t i=0; i<len; i++) {
@@ -220,9 +220,10 @@ static int secp256k1_ge_is_valid_var(const secp256k1_ge_t *a) {
 }
 
 static void secp256k1_gej_double_var(secp256k1_gej_t *r, const secp256k1_gej_t *a) {
-    // For secp256k1, 2Q is infinity if and only if Q is infinity. This is because if 2Q = infinity,
-    // Q must equal -Q, or that Q.y == -(Q.y), or Q.y is 0. For a point on y^2 = x^3 + 7 to have
-    // y=0, x^3 must be -7 mod p. However, -7 has no cube root mod p.
+    /** For secp256k1, 2Q is infinity if and only if Q is infinity. This is because if 2Q = infinity,
+     *  Q must equal -Q, or that Q.y == -(Q.y), or Q.y is 0. For a point on y^2 = x^3 + 7 to have
+     *  y=0, x^3 must be -7 mod p. However, -7 has no cube root mod p.
+     */
     r->infinity = a->infinity;
     if (r->infinity) {
         return;

src/hash_impl.h

@@ -128,21 +128,21 @@ static void secp256k1_sha256_write(secp256k1_sha256_t *hash, const unsigned char
     const unsigned char* end = data + len;
     size_t bufsize = hash->bytes % 64;
     if (bufsize && bufsize + len >= 64) {
-        // Fill the buffer, and process it.
+        /* Fill the buffer, and process it. */
         memcpy(hash->buf + bufsize, data, 64 - bufsize);
         hash->bytes += 64 - bufsize;
         data += 64 - bufsize;
         secp256k1_sha256_transform(hash->s, hash->buf);
         bufsize = 0;
     }
     while (end >= data + 64) {
-        // Process full chunks directly from the source.
+        /* Process full chunks directly from the source. */
         secp256k1_sha256_transform(hash->s, data);
         hash->bytes += 64;
         data += 64;
     }
     if (end > data) {
-        // Fill the buffer with what remains.
+        /* Fill the buffer with what remains. */
         memcpy(hash->buf + bufsize, data, end - data);
         hash->bytes += end - data;
     }

src/util.h

@@ -61,7 +61,7 @@
 #define VERIFY_CHECK(cond) do { (void)(cond); } while(0)
 #endif
 
-static inline void *checked_malloc(size_t size) {
+static SECP256K1_INLINE void *checked_malloc(size_t size) {
     void *ret = malloc(size);
     CHECK(ret != NULL);
     return ret;