Replaced some endianness-specific code with endianness-agnostic functions.

libslunkcrypt/src/slunkcrypt.c

@@ -9,6 +9,7 @@
 
 #include <slunkcrypt.h>
 #include <string.h>
+#include <assert.h>
 #include "version.h"
 
 #ifdef _MSC_VER
@@ -30,6 +31,9 @@ const uint16_t SLUNKCRYPT_VERSION_MINOR = MY_VERSION_MINOR;
 const uint16_t SLUNKCRYPT_VERSION_PATCH = MY_VERSION_PATCH;
 const char* const SLUNKCRYPT_BUILD = __DATE__ " " __TIME__;
 
+/* Const */
+#define MAGIC_PRIME 0x00000100000001B3ull
+
 // ==========================================================================
 // Data structures
 // ==========================================================================
@@ -74,26 +78,67 @@ volatile int g_slunkcrypt_abort_flag = 0;
 } \
 while (0)
 
+// ==========================================================================
+// Byte access (endianness agnostic)
+// ==========================================================================
+
+static FORCE_INLINE uint32_t lower_u64(const uint64_t value)
+{
+	return (uint32_t)(value & 0xFFFFFFFF);
+}
+
+static FORCE_INLINE uint32_t upper_u64(const uint64_t value)
+{
+	return (uint32_t)((value > 32U) & 0xFFFFFFFF);
+}
+
+static FORCE_INLINE uint8_t byte_u16(const uint16_t value, const size_t off)
+{
+	assert(index < sizeof(uint16_t));
+	return (uint8_t)((value >> (CHAR_BIT * off)) & 0xFF);
+}
+
+static FORCE_INLINE uint8_t byte_u64(const uint64_t value, const size_t off)
+{
+	assert(index < sizeof(uint64_t));
+	return (uint8_t)((value >> (CHAR_BIT * off)) & 0xFF);
+}
+
 // ==========================================================================
 // Hash function
 // ==========================================================================
 
-static FORCE_INLINE void hash_update(uint64_t *const h, const uint8_t* const data, const size_t data_len)
+static FORCE_INLINE void hash_update_str(uint64_t* const hash, const uint8_t* const data, const size_t data_len)
 {
 	for (size_t i = 0U; i < data_len; ++i)
 	{
-		*h ^= data[i];
+		*hash = ((*hash) ^ data[i]) * MAGIC_PRIME;
-		*h *= 0x00000100000001B3ull;
+	}
+}
+
+static FORCE_INLINE void hash_update_u64(uint64_t* const hash, const uint64_t value)
+{
+	for (size_t i = 0U; i < sizeof(uint64_t); ++i)
+	{
+		*hash = ((*hash) ^ byte_u64(value, i)) * MAGIC_PRIME;
+	}
+}
+
+static FORCE_INLINE void hash_update_u16(uint64_t* const hash, const uint16_t value)
+{
+	for (size_t i = 0U; i < sizeof(uint16_t); ++i)
+	{
+		*hash = ((*hash) ^ byte_u16(value, i)) * MAGIC_PRIME;
 	}
 }
 
 static uint64_t hash_code(const uint64_t salt, const uint16_t pepper, const uint8_t* const data, const size_t data_len)
 {
-	uint64_t h = 0xCBF29CE484222325ull;
+	uint64_t hash = 0xCBF29CE484222325ull;
-	hash_update(&h, (uint8_t*)&salt,   sizeof(uint64_t));
+	hash_update_u64(&hash, salt);
-	hash_update(&h, (uint8_t*)&pepper, sizeof(uint16_t));
+	hash_update_u16(&hash, pepper);
-	hash_update(&h, data, data_len);
+	hash_update_str(&hash, data, data_len);
-	return h;
+	return hash;
 }
 
 // ==========================================================================
@@ -122,10 +167,10 @@ static void generate_key(key_data_t *const key, const uint64_t salt, const uint1
 static void random_init(rand_state_t* const state, const uint64_t seed_0, const uint64_t seed_1)
 {
 	slunkcrypt_bzero(state, sizeof(rand_state_t));
-	state->a = (uint32_t)( seed_0        & 0xFFFFFFFF);
+	state->a = lower_u64(seed_0);
-	state->b = (uint32_t)((seed_0 >> 32) & 0xFFFFFFFF);
+	state->b = upper_u64(seed_0);
-	state->c = (uint32_t)( seed_1        & 0xFFFFFFFF);
+	state->c = lower_u64(seed_1);
-	state->d = (uint32_t)((seed_1 >> 32) & 0xFFFFFFFF);
+	state->d = upper_u64(seed_1);
 }
 
 static uint32_t random_next(rand_state_t *const state)