c: move c files into nostrdb in prep for switchover

nostrdb/mem.c

@@ -0,0 +1,128 @@
+/* CC0 (Public domain) - see LICENSE file for details */
+
+#include "config.h"
+
+#include <assert.h>
+#include <string.h>
+#include "mem.h"
+
+#if !HAVE_MEMMEM
+void *memmem(const void *haystack, size_t haystacklen,
+         const void *needle, size_t needlelen)
+{
+    const char *p;
+
+    if (needlelen > haystacklen)
+        return NULL;
+
+    p = haystack;
+
+    for (p = haystack;
+         (p + needlelen) <= ((const char *)haystack + haystacklen);
+         p++)
+        if (memcmp(p, needle, needlelen) == 0)
+            return (void *)p;
+
+    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;
+    size_t len;
+
+    /* Check first 16 bytes manually */
+    for (len = 0; len < 16; len++) {
+        if (!length)
+            return true;
+        if (*p)
+            return false;
+        p++;
+        length--;
+    }
+
+    /* Now we know that's zero, memcmp with self. */
+    return memcmp(data, p, length) == 0;
+}
+
+void memtaint(void *data, size_t len)
+{
+    /* Using 16 bytes is a bit quicker than 4 */
+    const unsigned tainter[]
+        = { 0xdeadbeef, 0xdeadbeef, 0xdeadbeef, 0xdeadbeef };
+    char *p = data;
+
+    while (len >= sizeof(tainter)) {
+        memcpy(p, tainter, sizeof(tainter));
+        p += sizeof(tainter);
+        len -= sizeof(tainter);
+    }
+    memcpy(p, tainter, len);
+
+#if HAVE_VALGRIND_MEMCHECK_H
+    VALGRIND_MAKE_MEM_UNDEFINED(data, len);
+#endif
+}