nga-c: implement more utf32_ functions

FossilOrigin-Name: 528dbf1960c805bee6c2048fda5b354e0c5bd02dc44bca787df9c7845c12039e

vm/nga-c/utf32.c

@@ -1,5 +1,41 @@
-int utf32_length(int *s, int max) {
-  int l = 0;
-  while (*s++ != 0 && l < max) l++;
-  return l;
+size_t utf32_strlen(const int32_t *utf32_str) {
+  size_t length = 0;
+  while (utf32_str[length] != 0) {
+    length++;
+  }
+  return length;
+}
+
+void utf32_strcpy(int32_t *dest, const int32_t *src) {
+  while ((*dest++ = *src++) != 0);
+}
+
+int utf32_strcmp(const int32_t *str1, const int32_t *str2) {
+  while (*str1 && (*str1 == *str2)) {
+    str1++;
+    str2++;
+  }
+  return *str1 - *str2;
+}
+
+void c_to_utf32(const char *source, int32_t *dest, int max) {
+  int i = 0;
+  while (source[i] != '\0' && i < max - 1) {
+    dest[i] = (int32_t)source[i];
+    i++;
+  }
+  dest[i] = 0;
+}
+
+void utf32_to_c(const int32_t *source, char *dest, int max) {
+  int i = 0;
+  while (source[i] != 0 && i < max - 1) {
+    if (source[i] <= 0x7F) {
+      dest[i] = (char)source[i];
+    } else {
+      dest[i] = '?';
+    }
+    i++;
+  }
+  dest[i] = '\0';
 }