Issue #16166: Add PY_LITTLE_ENDIAN and PY_BIG_ENDIAN macros and unified

endianess detection and handling.

1 files changed, 6 insertions, 16 deletions

diff --git a/Modules/sha256module.c b/Modules/sha256module.c
index 76d91afda3..4abd1cd43a 100644
--- a/Modules/sha256module.c
+++ b/Modules/sha256module.c
@@ -21,13 +21,6 @@
 #include "hashlib.h"
 
 
-/* Endianness testing and definitions */
-#define TestEndianness(variable) {int i=1; variable=PCT_BIG_ENDIAN;\
-        if (*((char*)&i)==1) variable=PCT_LITTLE_ENDIAN;}
-
-#define PCT_LITTLE_ENDIAN 1
-#define PCT_BIG_ENDIAN 0
-
 /* Some useful types */
 
 typedef unsigned char SHA_BYTE;
@@ -50,7 +43,6 @@ typedef struct {
     SHA_INT32 digest[8];                /* Message digest */
     SHA_INT32 count_lo, count_hi;       /* 64-bit bit count */
     SHA_BYTE data[SHA_BLOCKSIZE];       /* SHA data buffer */
-    int Endianness;
     int local;                          /* unprocessed amount in data */
     int digestsize;
 } SHAobject;
@@ -58,13 +50,11 @@ typedef struct {
 /* When run on a little-endian CPU we need to perform byte reversal on an
    array of longwords. */
 
-static void longReverse(SHA_INT32 *buffer, int byteCount, int Endianness)
+#if PY_LITTLE_ENDIAN
+static void longReverse(SHA_INT32 *buffer, int byteCount)
 {
     SHA_INT32 value;
 
-    if ( Endianness == PCT_BIG_ENDIAN )
-        return;
-
     byteCount /= sizeof(*buffer);
     while (byteCount--) {
         value = *buffer;
@@ -73,10 +63,10 @@ static void longReverse(SHA_INT32 *buffer, int byteCount, int Endianness)
         *buffer++ = ( value << 16 ) | ( value >> 16 );
     }
 }
+#endif
 
 static void SHAcopy(SHAobject *src, SHAobject *dest)
 {
-    dest->Endianness = src->Endianness;
     dest->local = src->local;
     dest->digestsize = src->digestsize;
     dest->count_lo = src->count_lo;
@@ -131,7 +121,9 @@ sha_transform(SHAobject *sha_info)
         SHA_INT32 S[8], W[64], t0, t1;
 
     memcpy(W, sha_info->data, sizeof(sha_info->data));
-    longReverse(W, (int)sizeof(sha_info->data), sha_info->Endianness);
+#if PY_LITTLE_ENDIAN
+    longReverse(W, (int)sizeof(sha_info->data));
+#endif
 
     for (i = 16; i < 64; ++i) {
                 W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];
@@ -228,7 +220,6 @@ sha_transform(SHAobject *sha_info)
 static void
 sha_init(SHAobject *sha_info)
 {
-    TestEndianness(sha_info->Endianness)
     sha_info->digest[0] = 0x6A09E667L;
     sha_info->digest[1] = 0xBB67AE85L;
     sha_info->digest[2] = 0x3C6EF372L;
@@ -246,7 +237,6 @@ sha_init(SHAobject *sha_info)
 static void
 sha224_init(SHAobject *sha_info)
 {
-    TestEndianness(sha_info->Endianness)
     sha_info->digest[0] = 0xc1059ed8L;
     sha_info->digest[1] = 0x367cd507L;
     sha_info->digest[2] = 0x3070dd17L;