Fix/simplify c_memccpy()

1 files changed, 6 insertions, 8 deletions

diff --git a/stc/cstr.h b/stc/cstr.h
index 5408548e..b1f2c11d 100644
--- a/stc/cstr.h
+++ b/stc/cstr.h
@@ -49,7 +49,7 @@ STC_API size_t  cstr_find(cstr_t s, const char* needle);
 STC_API size_t  cstr_find_n(cstr_t s, const char* needle, size_t pos, size_t nlen);

 STC_API size_t  cstr_ifind_n(cstr_t s, const char* needle, size_t pos, size_t nlen);

 

-STC_API void*   c_memccpy(void* restrict dst, const void* restrict src, int c, size_t n);

+STC_API void*   c_memccpy(void* dst, const void* src, int c, size_t n);

 STC_API int     c_strncasecmp(const char* s1, const char* s2, size_t n);

 STC_API char*   c_strnfind(const char* s, const char* needle, size_t nmax);

 STC_API char*   c_istrnfind(const char* s, const char* needle, size_t nmax);

@@ -395,15 +395,13 @@ cstr_ifind_n(cstr_t s, const char* needle, size_t pos, size_t nlen) {
 

 /* http://graphics.stanford.edu/~seander/bithacks.html#ZeroInWord */

 STC_DEF void*

-c_memccpy(void* restrict dst, const void* restrict src, int c, size_t n) {

+c_memccpy(void* dst, const void* src, int c, size_t n) {

     enum {w = sizeof(uintptr_t)};

-    #define __z (~(uintptr_t)0/255)

+    #define _mc_z (~(uintptr_t)0/255)

     const uint8_t* s = (const uint8_t *) src; uint8_t *d = (uint8_t *) dst, *e = d + n;

-    const uint8_t *align = (const uint8_t *)(((uintptr_t)s + w-1) & ~(w-1));

-    while (s != align) if ((*d++ = *s++) == (uint8_t) c) return d;

-    for (; d + w <= e; s += w, d += w) {

-        const uintptr_t x = *(uintptr_t *) s;

-        if (((x - __z) & ~x & __z*128) ^ (__z * (uint8_t) c)) break; /* hasvalue */

+    for (uintptr_t x; d + (w*2) <= e; s += w, d += w) {

+        memcpy(&x, s, w);

+        if (((x - _mc_z) & ~x & _mc_z*128) ^ (_mc_z*(uint8_t) c)) break; // hasvalue

         memcpy(d, &x, w);

     }

     while (d < e) if ((*d++ = *s++) == (uint8_t) c) return d;