BASE64 de/encoding - by Edward Flick - replace John Walkers implementation with http...

[citadel.git] / libcitadel / lib / b64 / cencode.c

diff --git a/libcitadel/lib/b64/cencode.c b/libcitadel/lib/b64/cencode.c
new file mode 100644 (file)
index 0000000..e440f37
--- /dev/null
+++ b/libcitadel/lib/b64/cencode.c
@@ -0,0 +1,99 @@
+/*
+cencoder.c - c source to a base64 encoding algorithm implementation
+
+This is part of the libb64 project, and has been placed in the public domain.
+For details, see http://sourceforge.net/projects/libb64
+*/
+
+#include "b64/cencode.h"
+
+void base64_init_encodestate(base64_encodestate* state_in)
+{
+       state_in->step = step_A;
+       state_in->result = 0;
+}
+
+char base64_encode_value(char value_in)
+{
+       static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+       if (value_in > 63) return '=';
+       return encoding[(int)value_in];
+}
+
+int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in)
+{
+       const char* plainchar = plaintext_in;
+       const char* const plaintextend = plaintext_in + length_in;
+       char* codechar = code_out;
+       char result;
+       char fragment;
+       
+       result = state_in->result;
+       
+       switch (state_in->step)
+       {
+               while (1)
+               {
+       case step_A:
+                       if (plainchar == plaintextend)
+                       {
+                               state_in->result = result;
+                               state_in->step = step_A;
+                               return codechar - code_out;
+                       }
+                       fragment = *plainchar++;
+                       result = (fragment & 0x0fc) >> 2;
+                       *codechar++ = base64_encode_value(result);
+                       result = (fragment & 0x003) << 4;
+       case step_B:
+                       if (plainchar == plaintextend)
+                       {
+                               state_in->result = result;
+                               state_in->step = step_B;
+                               return codechar - code_out;
+                       }
+                       fragment = *plainchar++;
+                       result |= (fragment & 0x0f0) >> 4;
+                       *codechar++ = base64_encode_value(result);
+                       result = (fragment & 0x00f) << 2;
+       case step_C:
+                       if (plainchar == plaintextend)
+                       {
+                               state_in->result = result;
+                               state_in->step = step_C;
+                               return codechar - code_out;
+                       }
+                       fragment = *plainchar++;
+                       result |= (fragment & 0x0c0) >> 6;
+                       *codechar++ = base64_encode_value(result);
+                       result  = (fragment & 0x03f) >> 0;
+                       *codechar++ = base64_encode_value(result);
+               }
+       }
+       /* control should not reach here */
+       return codechar - code_out;
+}
+
+int base64_encode_blockend(char* code_out, base64_encodestate* state_in)
+{
+       char* codechar = code_out;
+       
+       switch (state_in->step)
+       {
+       case step_B:
+               *codechar++ = base64_encode_value(state_in->result);
+               *codechar++ = '=';
+               *codechar++ = '=';
+               break;
+       case step_C:
+               *codechar++ = base64_encode_value(state_in->result);
+               *codechar++ = '=';
+               break;
+       case step_A:
+               break;
+       }
+       *codechar++ = '\n';
+       
+       return codechar - code_out;
+}
+