Implements C transpiler for pack function.

c/pack.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define pack_Nbit_(N)  \
+    static inline void biner_pack_l##N(const int##N##_t* v, uint8_t* c, size_t s) {  \
+      assert(s < N/8);  \
+      *c = (*v >> s*8) & 0xff;  \
+    } \
+    static inline void biner_pack_b##N(const int##N##_t* v, uint8_t* c, size_t s) {  \
+      assert(s < N/8);  \
+      biner_pack_l##N(v, c, N/8-s-1);  \
+    }
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define pack_Nbit_(N)  \
+    static inline void biner_pack_b##N(const int##N##_t* v, uint8_t* c, size_t s) {  \
+      assert(s < N/8);  \
+      *c = (*v >> s*8) & 0xff;  \
+    } \
+    static inline void biner_pack_l##N(const int##N##_t* v, uint8_t* c, size_t s) {  \
+      assert(s < N/8);  \
+      biner_pack_b##N(v, c, N/8-s-1);  \
+    }
+#else
+# error "byte order unknown"
+#endif
+
+pack_Nbit_(8);
+pack_Nbit_(16);
+pack_Nbit_(32);
+pack_Nbit_(64);
+
+#undef pack_Nbit_

c/unpack.h

@@ -8,7 +8,7 @@
 # define unpack_Nbit_(N)  \
     static inline void biner_unpack_l##N(int##N##_t* v, uint8_t c, size_t s) {  \
       assert(s < N/8);  \
-      *v = (*v & (0xff << (s*8))) | (c << (s*8));  \
+      *v = (*v & ~((uint##N##_t) 0xff << (s*8))) | (c << (s*8));  \
     } \
     static inline void biner_unpack_b##N(int##N##_t* v, uint8_t c, size_t s) {  \
       assert(s < N/8);  \
@@ -18,7 +18,7 @@
 # define unpack_Nbit_(N)  \
     static inline void biner_unpack_b##N(int##N##_t* v, uint8_t c, size_t s) {  \
       assert(s < N/8);  \
-      *v = (*v & (0xff << (s*8))) | (c << (s*8));  \
+      *v = (*v & ~((uint##N_t) 0xff << (s*8))) | (c << (s*8));  \
     } \
     static inline void biner_unpack_l##N(int##N##_t* v, uint8_t c, size_t s) {  \
       assert(s < N/8);  \