libk: add some tests

- merge types.h and type_traits.h

3 files changed, 80 insertions, 0 deletions

diff --git a/libk/string/integerview.cc b/libk/string/integerview.cc
new file mode 100644
index 0000000..beeb561
--- /dev/null
+++ b/libk/string/integerview.cc
@@ -0,0 +1,40 @@
+#include <string.h>
+
+/* itoa:  convert n to characters in s */
+template <typename T, int base = 10>
+constexpr size_t itoa(T n, char s[]) {
+  const bool is_negative = (n < 0);
+  if constexpr (!is_unsigned<T>()) {
+    if (n < 0)
+      n = -n;
+  }
+
+  int i = 0;
+  do {                                     /* generate digits in reverse order */
+    s[i++] = "0123456789abcdef"[n % base]; /* get next digit */
+  } while ((n /= base) > 0);               /* delete it */
+
+  if (is_negative)
+    s[i++] = '-';
+
+  s[i] = '\0';
+
+  // reverse(s, i);
+  return i;
+}
+
+IntegerView::IntegerView(int32_t n) {
+  length = itoa(n, buffer);
+}
+
+IntegerView::IntegerView(HexFormat_int32 f) {
+  length = itoa<int32_t, 16>(f.n, buffer);
+  buffer[length++] = 'x';
+  buffer[length++] = '0';
+}
+
+IntegerView::IntegerView(HexFormat_uint32 f) {
+  length = itoa<uint32_t, 16>(f.n, buffer);
+  buffer[length++] = 'x';
+  buffer[length++] = '0';
+}
diff --git a/libk/string/string.cc b/libk/string/string.cc
new file mode 100644
index 0000000..c75feb1
--- /dev/null
+++ b/libk/string/string.cc
@@ -0,0 +1,26 @@
+#include "string.h"
+
+// TODO
+
+// int strcpy(char *dst, const char *stc);
+// void strcat(void *dst, const void *src);
+// char* strncpy(char *dest, const char *src, int length);
+// int strncmp(const char *s1, const char *s2, int c);
+
+/* strcmp - compare two C-strings */
+constexpr int strcmp(const char* s1, const char* s2) {
+  const auto s1_len = strlen(s1);
+  for (size_t i = 0; i < s1_len; ++i) {
+    if (s1[i] == s2[i])
+      continue;
+    if (s1[i] > s2[i])
+      return 1;
+    if (s1[i] < s2[i])
+      return -1;
+  }
+  return 0;
+}
+
+static_assert(strcmp("one", "one") == 0);
+static_assert(strcmp("one", "two") < 0);
+static_assert(strcmp("foo", "bar") > 0);
diff --git a/libk/string/test.cc b/libk/string/test.cc
new file mode 100644
index 0000000..4d7d340
--- /dev/null
+++ b/libk/string/test.cc
@@ -0,0 +1,14 @@
+#include <string.h>
+
+// strlen
+static_assert(strlen("") == 0);
+static_assert(strlen("0") == 1);
+static_assert(strlen("hello") == 5);
+static_assert(strlen("world") == 5);
+
+// reverse
+static_assert([]() {
+  char s[] = "xyz";
+  reverse(s, strlen(s));
+  return s[0] == 'z' && s[1] == 'y' && s[2] == 'x' && s[3] == '\0';
+}());