1 files changed, 143 insertions, 0 deletions
diff --git a/src/string_util.c b/src/string_util.c
new file mode 100644
index 00000000..891d945c
--- /dev/null
+++ b/src/string_util.c
@@ -0,0 +1,143 @@
+#include "nitro.h"
+
+extern u32 gPowersOfTen[]; // at 0x20ECB24
+extern u16 gDigitTable[]; // at 0x20ECB08
+
+static const u16 EOS = 0xFFFF;
+
+void StringCopy(u16 *dest, const u16 *src)
+{
+    u16 c = *src;
+    while (c != EOS)
+    {
+        src++;
+        *dest = c;
+        c = *src;
+        dest++;
+    }
+    *dest = EOS;
+}
+
+u16 *StringCopyN(u16 *dest, const u16 *src, u32 num)
+{
+    u32 copied = 0;
+    if (num > copied)
+    {
+        u16 *p = dest;
+        do
+        {
+            u16 c = *src;
+            copied++;
+            src++;
+            *p = c;
+            p++;
+        } while (num > copied);
+    }
+    return dest + num;
+}
+
+u32 StringLength(const u16 *s)
+{
+    u16 c = *s;
+    u32 len = 0;
+    while (c != EOS)
+    {
+        s++;
+        c = *s;
+        len++;
+    }
+    return len;
+}
+
+BOOL StringNotEqual(const u16 *s1, const u16 *s2)
+{
+    for (; *s1 == *s2; s1++, s2++)
+    {
+        if (*s1 == EOS)
+            return FALSE;
+    }
+    return TRUE;
+}
+
+BOOL StringNotEqualN(const u16 *s1, const u16 *s2, u32 num)
+{
+    u16 c1, c2;
+    c2 = *s2;
+    c1 = *s1;
+    while (c1 == c2)
+    {
+        if (num == 0)
+        {
+            return FALSE;
+        }
+        if (*s1 == EOS && *s2 == EOS)
+        {
+            return FALSE;
+        }
+        s1++;
+        s2++;
+        c2 = *s2;
+        c1 = *s1;
+        num--;
+    }
+    return TRUE;
+}
+
+u16 *StringFill(u16 *dest, u16 value, u32 num)
+{
+    u32 copied = 0;
+    if (num > copied)
+    {
+        u16 *p = dest;
+        do
+        {
+            copied++;
+            *p = value;
+            p++;
+        } while (copied < num);
+    }
+    return dest + copied;
+}
+
+u16 *StringFillEOS(u16 *dest, u32 num)
+{
+    return StringFill(dest, EOS, num);
+}
+
+enum PrintingMode
+{
+    NORMAL,
+    PAD_SPACE,
+    PAD_ZEROES
+};
+
+const u16 NON_DIGIT = 0xE2;
+
+u16 *ConvertUIntToDecimalString(u16 *dest, u32 value, enum PrintingMode mode, u32 n)
+{
+    for (u32 x = gPowersOfTen[n];
+         x != 0;
+         x = x / 10)
+    {
+        u16 res = value / x;
+        value = value - x * res;
+        if (mode == PAD_ZEROES)
+        {
+            *dest = res >= 10 ? NON_DIGIT : gDigitTable[res];
+            dest++;
+        }
+        else if (res != 0 || x == 1)
+        {
+            mode = PAD_ZEROES;
+            *dest = res >= 10 ? NON_DIGIT : gDigitTable[res];
+            dest++;
+        }
+        else if (mode == PAD_SPACE)
+        {
+            *dest = 1;
+            dest++;
+        }
+    }
+    *dest = EOS;
+    return dest;
+}