mem: optimize.

[ccan] / ccan / mem / mem.c

diff --git a/ccan/mem/mem.c b/ccan/mem/mem.c
index ce675ff0db4238b6840fcdd98bff736ba90b508c..af41f9e011edbc6738667c3fc89d9d043b1dbcf6 100644 (file)
--- a/ccan/mem/mem.c
+++ b/ccan/mem/mem.c
@@ -2,6 +2,7 @@
 
 #include "config.h"
 
+#include <assert.h>
 #include <string.h>
 #include <ccan/mem/mem.h>
 
@@ -25,3 +26,79 @@ void *memmem(const void *haystack, size_t haystacklen,
        return NULL;
 }
 #endif
+
+#if !HAVE_MEMRCHR
+void *memrchr(const void *s, int c, size_t n)
+{
+       unsigned char *p = (unsigned char *)s;
+
+       while (n) {
+               if (p[n-1] == c)
+                       return p + n - 1;
+               n--;
+       }
+
+       return NULL;
+}
+#endif
+
+void *mempbrkm(const void *data_, size_t len, const void *accept_, size_t accept_len)
+{
+       const char *data = data_, *accept = accept_;
+       size_t i, j;
+
+       for (i = 0; i < len; i++)
+               for (j = 0; j < accept_len; j++)
+                       if (accept[j] == data[i])
+                               return (void *)&data[i];
+       return NULL;
+}
+
+void *memcchr(void const *data, int c, size_t data_len)
+{
+       char const *p = data;
+       size_t i;
+
+       for (i = 0; i < data_len; i++)
+               if (p[i] != c)
+                       return (void *)&p[i];
+
+       return NULL;
+}
+
+#define MEMSWAP_TMP_SIZE       256
+
+void memswap(void *a, void *b, size_t n)
+{
+       char *ap = a;
+       char *bp = b;
+       char tmp[MEMSWAP_TMP_SIZE];
+
+       assert(!memoverlaps(a, n, b, n));
+
+       while (n) {
+               size_t m = n > MEMSWAP_TMP_SIZE ? MEMSWAP_TMP_SIZE : n;
+
+               memcpy(tmp, bp, m);
+               memcpy(bp, ap, m);
+               memcpy(ap, tmp, m);
+
+               ap += m;
+               bp += m;
+               n -= m;
+       }
+}
+
+bool memeqzero(const void *data, size_t length)
+{
+       const unsigned char *p = data;
+       static unsigned long zeroes[16];
+
+       while (length > sizeof(zeroes)) {
+               if (memcmp(zeroes, p, sizeof(zeroes)))
+                       return false;
+               p += sizeof(zeroes);
+               length -= sizeof(zeroes);
+       }
+       return memcmp(zeroes, p, length) == 0;
+}