Making some MSL_C progress (#549)

src/MSL_C.PPCEABI.bare.H/mbstring.c

@@ -1,18 +1,64 @@
-#include "PowerPC_EABI_Support/Msl/MSL_C/MSL_Common/mbstring.h"
+#include "PowerPC_EABI_Support/Msl/MSL_C/MSL_Common/ansi_files.h"
 
-size_t wcstombs(char* s, const wchar_t* pwcs, size_t n)
-{
-	wchar_t next;
-	size_t chars_written;
-	int i;
+static int unicode_to_UTF8(char* s, wchar_t wchar) {
+    int number_of_bytes;
+    char* target_ptr;
+    char first_byte_mark[4] = {0x00, 0x00, 0xc0, 0xe0};
 
-	chars_written = 0;
-	for (i = 0; i < n; ++i) {
-		next = *pwcs++;
-		*s++ = (char)next;
-		if ((char)next == '\0')
-			break;
-		++chars_written;
-	}
-	return chars_written;
+    if (!s) {
+        return 0;
+    }
+
+    if (wchar < 0x0080)
+        number_of_bytes = 1;
+    else if (wchar < 0x0800)
+        number_of_bytes = 2;
+    else
+        number_of_bytes = 3;
+
+    target_ptr = s + number_of_bytes;
+
+    switch (number_of_bytes) {
+    case 3:
+        *--target_ptr = (wchar & 0x003f) | 0x80;
+        wchar >>= 6;
+    case 2:
+        *--target_ptr = (wchar & 0x003f) | 0x80;
+        wchar >>= 6;
+    case 1:
+        *--target_ptr = wchar | first_byte_mark[number_of_bytes];
+    }
+
+    return (number_of_bytes);
+}
+
+static inline int wctomb(char* s, wchar_t wchar) {
+	return (unicode_to_UTF8(s, wchar));
+}
+
+size_t wcstombs(char* s, const wchar_t* pwcs, size_t n) {
+    int chars_written = 0;
+    int result;
+    char temp[3];
+    wchar_t* source;
+
+    if (!s || !pwcs)
+        return (0);
+
+    source = (wchar_t*)pwcs;
+    while (chars_written <= n) {
+        if (!*source) {
+            *(s + chars_written) = '\0';
+            break;
+        } else {
+            result = wctomb(temp, *source++);
+            if ((chars_written + result) <= n) {
+                strcat(s + chars_written, temp, result);
+                chars_written += result;
+            } else
+                break;
+        }
+    }
+
+    return (chars_written);
 }