java: public static final int prev(byte[] b, int ptr, char chrA) {if (ptr == b.length)--ptr;while (ptr >= 0) {if (b[ptr--] == chrA)return ptr;}return ptr;}
C#: public static int Prev(byte[] b, int ptr, char chrA){if (ptr == b.Length){--ptr;}while (ptr >= 0){if (b[ptr--] == chrA){return ptr;}}return ptr;}