Created string.h header; moved code to string.c

src/string.c

@@ -0,0 +1,110 @@
+#include "string.h"
+#include <stdbool.h>
+#include <stdint.h>
+
+void *memcpy(void *destination, const void *source, size_t num)
+{
+    if (num > 0)
+    {
+        const uint8_t *src = (const uint8_t *)source;
+        uint8_t *dest = (uint8_t *)destination;
+        for (size_t i = 0; i < num; i++)
+        {
+            dest[i] = src[i];
+        }
+    }
+    return destination;
+}
+
+void *memmove(void *destination, const void *source, size_t num)
+{
+    if (num > 0)
+    {
+        if (((size_t)destination) < ((size_t)source) || ((size_t)destination) >= (((size_t)source)) + num)
+        {
+            return memcpy(destination, source, num);
+        }
+        else if (destination != source)
+        {
+            size_t i = num - 1;
+            const uint8_t *src = (const uint8_t *)source;
+            uint8_t *dest = (uint8_t *)destination;
+            do
+            {
+                dest[i] = src[i];
+                i--;
+            } while (i != 0);
+        }
+    }
+    return destination;
+}
+
+int memcmp(const void *ptr1, const void *ptr2, size_t num)
+{
+    const uint8_t *a = (const uint8_t *)ptr1;
+    const uint8_t *b = (const uint8_t *)ptr2;
+    for (size_t i = 0; i < num; i++)
+    {
+        if (a[i] < b[i])
+            return -1;
+        else if (a[i] > b[i])
+            return 1;
+    }
+    return 0;
+}
+
+void *memset(void *ptr, int value, size_t num)
+{
+    uint8_t *dest = (uint8_t *)ptr;
+    uint8_t v = (uint8_t)value;
+    for (size_t i = 0; i < num; i++)
+    {
+        dest[i] = v;
+    }
+    return ptr;
+}
+
+int strlen(const char *str)
+{
+    int i = 0;
+    while (str[i] != '\0')
+    {
+        i++;
+    }
+    return i;
+}
+
+char *strcpy(char *destination, const char *source)
+{
+    int sourceLen = strlen(source);
+    if ((destination <= source) || (destination > (source + sourceLen)))
+    {
+        char *d = destination;
+        const char *s = source;
+        while (true)
+        {
+            *d = *s;
+            if (*s == '\0')
+            {
+                break;
+            }
+            else
+            {
+                s++;
+                d++;
+            }
+        }
+    }
+    else
+    {
+        char *d = destination + sourceLen;
+        const char *s = source + sourceLen;
+        do
+        {
+            *d = *s;
+            d--;
+            s--;
+        } while (d > destination);
+    }
+    return destination;
+}