Move string functions to libstring

libstring/.gitignore

@@ -0,0 +1 @@
+*.o

libstring/Makefile

@@ -0,0 +1,28 @@
+cc := clang
+o :=
+c :=
+cflags  := -isystem . -isystem ../libmsl
+buildtype ?= release
+
+include src.mk
+include ../generic/flags.mk
+include ../$(platform)/flags.mk
+
+all: build/libstring.a
+
+build/libstring.a: $(o)
+	llvm-ar rcs $@ $^
+
+%.o: %.c
+	$(cc) -c -o $@ $(cflags) $<
+
+%.o: %.S
+	$(cc) -c -o $@ $(cflags) $<
+
+clean:
+	rm -f $(o) build/libstring.a
+
+format:
+	clang-format -i $$(git ls-files '*.c' '*.h')
+
+.PHONY: all clean format

libstring/src.mk

@@ -0,0 +1,3 @@
+c += string.c
+
+o += string.o

libstring/string.c

@@ -0,0 +1,47 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+size_t memset (void* dst, uint8_t b, size_t n) {
+  uint8_t* dst1 = dst;
+  size_t i;
+  for (i = 0; i < n; i++)
+    dst1[i] = b;
+  return i;
+}
+
+size_t memcpy (void* dst, const void* src, size_t n) {
+  uint8_t* dst1 = dst;
+  const uint8_t* src1 = src;
+  size_t i;
+  for (i = 0; i < n; i++)
+    dst1[i] = src1[i];
+  return i;
+}
+
+// SOURCE: https://stackoverflow.com/a/48967408
+void strncpy (char* dst, const char* src, size_t n) {
+  size_t i = 0;
+  while (i++ != n && (*dst++ = *src++))
+    ;
+}
+
+size_t strlen (const char* str) {
+  const char* s;
+  for (s = str; *s; ++s)
+    ;
+  return (s - str);
+}
+
+int memcmp (const void* s1, const void* s2, size_t n) {
+  unsigned char* p = (unsigned char*)s1;
+  unsigned char* q = (unsigned char*)s2;
+
+  while (n--) {
+    if (*p != *q) {
+      return (int)*p - (int)*q;
+    }
+    p++, q++;
+  }
+  return 0;
+}

libstring/string.h

@@ -0,0 +1,13 @@
+#ifndef _LIBSTRING_STRING_H
+#define _LIBSTRING_STRING_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+size_t memset (void* dst, uint8_t b, size_t n);
+size_t memcpy (void* dst, const void* src, size_t n);
+void strncpy (char* dst, const char* src, size_t n);
+size_t strlen (const char* str);
+int memcmp (const void* s1, const void* s2, size_t n);
+
+#endif // _LIBSTRING_STRING_H