shachain: remove unnecessary shachain_index_t

You can use SHACHAIN_BITS to contrain the size.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/crypto/shachain/shachain.c

@@ -10,7 +10,7 @@ static void change_bit(unsigned char *arr, size_t index)
 	arr[index / CHAR_BIT] ^= (1 << (index % CHAR_BIT));
 }
 
-static unsigned int count_trailing_zeroes(shachain_index_t index)
+static unsigned int count_trailing_zeroes(uint64_t index)
 {
 #if HAVE_BUILTIN_CTZLL
 	return index ? (unsigned int)__builtin_ctzll(index) : SHACHAIN_BITS;
@@ -25,24 +25,24 @@ static unsigned int count_trailing_zeroes(shachain_index_t index)
 #endif
 }
 
-static bool can_derive(shachain_index_t from, shachain_index_t to)
+static bool can_derive(uint64_t from, uint64_t to)
 {
-	shachain_index_t mask;
+	uint64_t mask;
 
 	/* Corner case: can always derive from seed. */
 	if (from == 0)
 		return true;
 
 	/* Leading bits must be the same */
-	mask = ~((1ULL << count_trailing_zeroes(from))-1);
+	mask = ~(((uint64_t)1 << count_trailing_zeroes(from))-1);
 	return ((from ^ to) & mask) == 0;
 }
 
-static void derive(shachain_index_t from, shachain_index_t to,
+static void derive(uint64_t from, uint64_t to,
 		   const struct sha256 *from_hash,
 		   struct sha256 *hash)
 {
-	shachain_index_t branches;
+	uint64_t branches;
 	int i;
 
 	assert(can_derive(from, to));
@@ -60,13 +60,13 @@ static void derive(shachain_index_t from, shachain_index_t to,
 	}
 }
 
-void shachain_from_seed(const struct sha256 *seed, shachain_index_t index,
+void shachain_from_seed(const struct sha256 *seed, uint64_t index,
 			struct sha256 *hash)
 {
 	derive(0, index, seed, hash);
 }
 
-shachain_index_t shachain_next_index(const struct shachain *chain)
+uint64_t shachain_next_index(const struct shachain *chain)
 {
 	return chain->min_index - 1;
 }
@@ -75,11 +75,11 @@ void shachain_init(struct shachain *chain)
 {
 	chain->num_valid = 0;
 	/* This is 0 in the case where SHACHAIN_BITS is 64. */
-	chain->min_index = (shachain_index_t)((UINT64_MAX >> (64 - SHACHAIN_BITS)) + 1);
+	chain->min_index = (UINT64_MAX >> (64 - SHACHAIN_BITS)) + 1;
 }
 
 bool shachain_add_hash(struct shachain *chain,
-		       shachain_index_t index, const struct sha256 *hash)
+		       uint64_t index, const struct sha256 *hash)
 {
 	unsigned int i, pos;
 
@@ -108,7 +108,7 @@ bool shachain_add_hash(struct shachain *chain,
 }
 
 bool shachain_get_hash(const struct shachain *chain,
-		       shachain_index_t index, struct sha256 *hash)
+		       uint64_t index, struct sha256 *hash)
 {
 	unsigned int i;
 

ccan/crypto/shachain/shachain.h

@@ -6,13 +6,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-/* Useful for testing. */
-#ifndef shachain_index_t
-#define shachain_index_t uint64_t
-#endif
-
 #ifndef SHACHAIN_BITS
-#define SHACHAIN_BITS (sizeof(shachain_index_t) * 8)
+#define SHACHAIN_BITS (sizeof(uint64_t) * 8)
 #endif
 
 /**
@@ -42,7 +37,7 @@
  *	shachain_from_seed(&seed, index--, hash);
  * }
  */
-void shachain_from_seed(const struct sha256 *seed, shachain_index_t index,
+void shachain_from_seed(const struct sha256 *seed, uint64_t index,
 			struct sha256 *hash);
 
 /**
@@ -55,10 +50,10 @@ void shachain_from_seed(const struct sha256 *seed, shachain_index_t index,
  * added.
  */
 struct shachain {
-	shachain_index_t min_index;
+	uint64_t min_index;
 	unsigned int num_valid;
 	struct {
-		shachain_index_t index;
+		uint64_t index;
 		struct sha256 hash;
 	} known[SHACHAIN_BITS + 1];
 };
@@ -79,7 +74,7 @@ void shachain_init(struct shachain *chain);
  * initialized chain), or one less than the previously successfully
  * added value.
  */
-shachain_index_t shachain_next_index(const struct shachain *chain);
+uint64_t shachain_next_index(const struct shachain *chain);
 
 /**
  * shachain_add_hash - record the hash for the next index.
@@ -106,7 +101,7 @@ shachain_index_t shachain_next_index(const struct shachain *chain);
  * }
  */
 bool shachain_add_hash(struct shachain *chain,
-		       shachain_index_t index, const struct sha256 *hash);
+		       uint64_t index, const struct sha256 *hash);
 
 /**
  * shachain_get_hash - get the hash for a given index.
@@ -137,5 +132,5 @@ bool shachain_add_hash(struct shachain *chain,
  * }
  */
 bool shachain_get_hash(const struct shachain *chain,
-		       shachain_index_t index, struct sha256 *hash);
+		       uint64_t index, struct sha256 *hash);
 #endif /* CCAN_CRYPTO_SHACHAIN_H */

ccan/crypto/shachain/test/run-8bit.c

-#define shachain_index_t uint8_t
+#define SHACHAIN_BITS 8
 
 #include <ccan/crypto/shachain/shachain.h>
 /* Include the C files directly. */

ccan/crypto/shachain/test/run-can_derive.c

@@ -7,13 +7,13 @@
 
 #include <stdio.h>
 
-static bool bit_set(shachain_index_t index, int bit)
+static bool bit_set(uint64_t index, int bit)
 {
 	return index & (1ULL << bit);
 }
 
 /* As per design.txt */
-static bool naive_can_derive(shachain_index_t from, shachain_index_t to)
+static bool naive_can_derive(uint64_t from, shachain_index_t to)
 {
 	int i;