libk: add some tests

- merge types.h and type_traits.h

10 files changed, 127 insertions, 113 deletions

diff --git a/libk/makefile b/libk/makefile
index 941d93d..ea684ba 100644
--- a/libk/makefile
+++ b/libk/makefile
@@ -1,6 +1,6 @@
 
-CXX_OBJ := string.o stdlib/console.o
-CXX_TEST_OBJ := type_traits/test.o
+CXX_OBJ := string/string.o string/integerview.o stdlib/console.o
+CXX_TEST_OBJ := types/test.o string/test.o
 
 libk.a: $(CXX_OBJ)
 	$(AR) rcs $@ $(CXX_OBJ)
diff --git a/libk/stdlib.h b/libk/stdlib.h
index f031408..e1d3dd2 100644
--- a/libk/stdlib.h
+++ b/libk/stdlib.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <string.h>
-#include <type_traits.h>
 
 class Console {
  public:
diff --git a/libk/string.h b/libk/string.h
index 0675cea..03c0942 100644
--- a/libk/string.h
+++ b/libk/string.h
@@ -1,5 +1,4 @@
 #pragma once
-#include <type_traits.h>
 #include <types.h>
 
 /**
@@ -8,13 +7,15 @@
  */
 constexpr size_t strlen(const char* str) {
   size_t len = 0;
-  while (str[len])
+  while (str[len] != '\0')
     ++len;
   return len;
 }
 
-/* reverse:  reverse string s in place */
-constexpr void reverse(char s[], int strlen) {
+/**
+ * Reverse array in place
+ */
+constexpr void reverse(char s[], size_t strlen) {
   int i, j;
   char c;
 
@@ -25,57 +26,29 @@ constexpr void reverse(char s[], int strlen) {
   }
 }
 
-/* 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;
-}
-
 class ViewIterator {
 public:
-  virtual char next() = 0;
-  virtual operator bool() const = 0;
-};
-
-class StringView {
-public:
-  class Iterator : public ViewIterator {
-    friend class StringView;
+  char next() { return buffer[reverse ? pos-- : pos++]; }
+  operator bool() const { return reverse ? (pos >= 0) : (pos < length); }
 
-  public:
-    char next() override { return p->buffer[pos++]; }
-    operator bool() const override { return (pos < p->m_length); }
-
-  private:
-    Iterator(const StringView* s) : p(s) {}
-
-    size_t pos = 0;
-    const StringView* p;
+  explicit ViewIterator(const char* b, size_t l, bool r = false) : buffer(b), length(l), reverse(r) {
+    if (reverse)
+      pos = length - 1;
   };
 
-  friend class Iterator;
+private:
+  ssize_t pos = 0;
+  const char* const buffer;  // const pointer to const char*
+  const size_t length;
+  const bool reverse;
+};
 
+class StringView {
+public:
   StringView(const char* d) : buffer{d}, m_length{strlen(d)} {}
   StringView(const char* d, size_t l) : buffer{d}, m_length{l} {}
 
-  Iterator begin() const { return Iterator(this); }
+  auto begin() const { return ViewIterator(buffer, m_length); }
 
 private:
   const char* const buffer;
@@ -84,42 +57,25 @@ private:
 
 class IntegerView {
 public:
-  template <typename T>
-  struct HexFormat {
-    T n;
+  struct HexFormat_int32 {
+    int32_t n;
   };
-
-  class Iterator : public ViewIterator {
-    friend class IntegerView;
-
-  public:
-    char next() override { return _p->buffer[pos++]; };
-    operator bool() const override { return (pos < _p->length); }
-
-  private:
-    Iterator(const IntegerView* v) : _p(v) {}
-
-    size_t pos = 0;
-    const IntegerView* _p;
+  struct HexFormat_uint32 {
+    uint32_t n;
   };
 
-  IntegerView(int32_t n) { length = itoa(n, buffer); }
-
-  template <typename T>
-  IntegerView(HexFormat<T> f) {
-    buffer[0] = '0';
-    buffer[1] = 'x';
-    length = itoa<T, 16>(f.n, buffer + 2) + 2;
-  }
+  IntegerView(int32_t n);
+  IntegerView(HexFormat_int32 f);
+  IntegerView(HexFormat_uint32 f);
 
-  Iterator begin() const { return Iterator(this); }
+  auto begin() const { return ViewIterator(buffer, length, true); }
 
 private:
-  char buffer[128];
+  char buffer[32];
   size_t length = 0;
 };
 
-using hex = IntegerView::HexFormat<int32_t>;
-using uhex = IntegerView::HexFormat<uint32_t>;
+using hex = IntegerView::HexFormat_int32;
+using uhex = IntegerView::HexFormat_uint32;
 
-using hex_addr = IntegerView::HexFormat<uint64_t>;  // TODO causes crash
+// using hex_addr = IntegerView::HexFormat<uint64_t>;  // TODO causes crash
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.cc b/libk/string/string.cc
index c75feb1..c75feb1 100644
--- a/libk/string.cc
+++ b/libk/string/string.cc
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';
+}());
diff --git a/libk/type_traits.h b/libk/type_traits.h
deleted file mode 100644
index dc70339..0000000
--- a/libk/type_traits.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#pragma once
-
-template <class T, T v>
-struct integral_constant {
-  constexpr T operator()() const { return v; }
-  constexpr operator T() const { return v; }
-};
-
-template <class T, class U>
-struct is_same : integral_constant<bool, false> {};
-
-template <class T>
-struct is_same<T, T> : integral_constant<bool, true> {};
-
-template <typename T>
-struct is_unsigned : integral_constant<bool, (T{0} < static_cast<T>(-1))> {};
diff --git a/libk/types.h b/libk/types.h
index fc20d22..4018ab8 100644
--- a/libk/types.h
+++ b/libk/types.h
@@ -1,28 +1,33 @@
 #pragma once
 
 typedef unsigned short size_t;
-static_assert(sizeof(size_t) >= 2);
+typedef int ssize_t;
 
 typedef unsigned char uint8_t;
-static_assert(sizeof(uint8_t) == 1);
-
 typedef unsigned short uint16_t;
-static_assert(sizeof(uint16_t) == 2);
-
 typedef unsigned int uint32_t;
-static_assert(sizeof(uint32_t) == 4);
-
 typedef unsigned long long int uint64_t;
-static_assert(sizeof(uint64_t) == 8);
 
 typedef char int8_t;
-static_assert(sizeof(int8_t) == 1);
-
 typedef short int16_t;
-static_assert(sizeof(int16_t) == 2);
-
 typedef int int32_t;
-static_assert(sizeof(int32_t) == 4);
-
 typedef long long int int64_t;
-static_assert(sizeof(int64_t) == 8);
+
+// Type Traits
+
+template <class T, T v>
+struct integral_constant {
+  constexpr T operator()() const { return v; }
+  constexpr operator T() const { return v; }
+};
+
+/* is_same */
+template <class T, class U>
+struct is_same : integral_constant<bool, false> {};
+
+template <class T>
+struct is_same<T, T> : integral_constant<bool, true> {};
+
+/* is_unsigned */
+template <typename T>
+struct is_unsigned : integral_constant<bool, (T{0} < static_cast<T>(-1))> {};
diff --git a/libk/type_traits/test.cc b/libk/types/test.cc
index 1aa11df..f93d883 100644
--- a/libk/type_traits/test.cc
+++ b/libk/types/test.cc
@@ -1,6 +1,18 @@
-#include <type_traits.h>
 #include <types.h>
 
+// types
+static_assert(sizeof(size_t) >= 2);
+
+static_assert(sizeof(uint8_t) == 1);
+static_assert(sizeof(uint16_t) == 2);
+static_assert(sizeof(uint32_t) == 4);
+static_assert(sizeof(uint64_t) == 8);
+
+static_assert(sizeof(int8_t) == 1);
+static_assert(sizeof(int16_t) == 2);
+static_assert(sizeof(int32_t) == 4);
+static_assert(sizeof(int64_t) == 8);
+
 // is_same
 static_assert(is_same<int, int>() == true);
 static_assert(is_same<int, unsigned int>() == false);
diff --git a/makefile b/makefile
index f45d65a..1a50a18 100644
--- a/makefile
+++ b/makefile
@@ -6,8 +6,12 @@
 export TARGET := i686-elf
 
 export AR := llvm-ar
-export AS := clang
-export LD := ld.lld
+
+AS := clang
+
+LD := ld.lld
+LD_FLAGS := -T linker.ld -lk
+
 export CXX := clang
 export CXX_FLAGS := -std=c++20 -ffreestanding -nostdlib -nostdinc -nostdinc++ \
 		    -fno-exceptions -fno-rtti -Wall -Wextra -O2
@@ -24,7 +28,7 @@ check-grub: glitch.elf
 	grub-file --is-x86-multiboot2 glitch.elf
 
 glitch.elf: boot.o $(CXX_OBJ) libk/libk.a
-	$(LD) -T linker.ld -o glitch.elf boot.o $(CXX_OBJ) -lk
+	$(LD) $(LD_FLAGS) -o $@ boot.o $(CXX_OBJ)
 
 boot.o: boot.s
 	$(AS) -target $(TARGET) -nostdlib -Wall -Wextra -c $^ -o $@