feat: lib seaHEADmain

1 files changed, 92 insertions, 0 deletions

diff --git a/sysroot/usr/lib/libc/string.c b/sysroot/usr/lib/libc/string.c
new file mode 100644
index 0000000..7bbc0c2
--- /dev/null
+++ b/sysroot/usr/lib/libc/string.c
@@ -0,0 +1,92 @@
+#include <string.h>
+
+size_t strlen(const char* string)
+{
+    size_t length = 0;
+    while (string[length])
+        length++;
+    return length;
+}
+
+int strcmp(const char* a, const char* b)
+{
+    while (*a && *a == *b)
+    {
+        a++;
+        b++;
+    }
+
+    return (int)(unsigned char)*a - (int)(unsigned char)*b;
+}
+
+int strncmp(const char* a, const char* b, size_t length)
+{
+    for (size_t i = 0; i < length; i++)
+    {
+        unsigned char ca = (unsigned char)a[i];
+        unsigned char cb = (unsigned char)b[i];
+        if (ca != cb)
+            return (int)ca - (int)cb;
+        if (ca == 0)
+            return 0;
+    }
+    return 0;
+}
+
+char* strcpy(char* destination, const char* source)
+{
+    char* out = destination;
+    while ((*out++ = *source++))
+        ;
+    return destination;
+}
+
+char* strncpy(char* destination, const char* source, size_t length)
+{
+    size_t i = 0;
+    for (; i < length && source[i]; i++)
+        destination[i] = source[i];
+    for (; i < length; i++)
+        destination[i] = 0;
+    return destination;
+}
+
+void* memcpy(void* destination, const void* source, size_t length)
+{
+    unsigned char* out = destination;
+    const unsigned char* in = source;
+    for (size_t i = 0; i < length; i++)
+        out[i] = in[i];
+    return destination;
+}
+
+void* memmove(void* destination, const void* source, size_t length)
+{
+    unsigned char* out = destination;
+    const unsigned char* in = source;
+    if (out < in)
+        for (size_t i = 0; i < length; i++)
+            out[i] = in[i];
+    else
+        for (size_t i = length; i > 0; i--)
+            out[i - 1] = in[i - 1];
+    return destination;
+}
+
+void* memset(void* destination, int value, size_t length)
+{
+    unsigned char* out = destination;
+    for (size_t i = 0; i < length; i++)
+        out[i] = (unsigned char)value;
+    return destination;
+}
+
+int memcmp(const void* a, const void* b, size_t length)
+{
+    const unsigned char* aa = a;
+    const unsigned char* bb = b;
+    for (size_t i = 0; i < length; i++)
+        if (aa[i] != bb[i])
+            return (int)aa[i] - (int)bb[i];
+    return 0;
+}