优化了平衡，尤其对于向后倾倒的几种极限情况进行优化

Shibo-main-TOMMY/lib/WebSockets/src/libb64/cdecode_inc.h

@@ -0,0 +1,28 @@
+/*
+cdecode.h - c header for a base64 decoding algorithm
+
+This is part of the libb64 project, and has been placed in the public domain.
+For details, see http://sourceforge.net/projects/libb64
+*/
+
+#ifndef BASE64_CDECODE_H
+#define BASE64_CDECODE_H
+
+typedef enum
+{
+	step_a, step_b, step_c, step_d
+} base64_decodestep;
+
+typedef struct
+{
+	base64_decodestep step;
+	char plainchar;
+} base64_decodestate;
+
+void base64_init_decodestate(base64_decodestate* state_in);
+
+int base64_decode_value(char value_in);
+
+int base64_decode_block(const char* code_in, const int length_in, char* plaintext_out, base64_decodestate* state_in);
+
+#endif /* BASE64_CDECODE_H */