base64.c
changeset 0 d7ee4e2ed49d
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-1:000000000000 0:d7ee4e2ed49d
       
     1 /*
       
     2 cdecoder.c - c source to a base64 decoding algorithm implementation
       
     3 
       
     4 This is part of the libb64 project, and has been placed in the public domain.
       
     5 For details, see http://sourceforge.net/projects/libb64
       
     6 */
       
     7 
       
     8 #include "base64.h"
       
     9 
       
    10 int base64_decode_value(char value_in)
       
    11 {
       
    12 	static const char decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};
       
    13 	static const char decoding_size = sizeof(decoding);
       
    14 	value_in -= 43;
       
    15 	if (value_in < 0 || value_in > decoding_size) return -1;
       
    16 	return decoding[(int)value_in];
       
    17 }
       
    18 
       
    19 void base64_init_decodestate(base64_decodestate* state_in)
       
    20 {
       
    21 	state_in->step = step_a;
       
    22 	state_in->plainchar = 0;
       
    23 }
       
    24 
       
    25 int base64_decode_block(const char* code_in, const int length_in, uint8_t* plaintext_out, base64_decodestate* state_in)
       
    26 {
       
    27 	const char* codechar = code_in;
       
    28 	uint8_t* plainchar = plaintext_out;
       
    29 	char fragment;
       
    30 	
       
    31 	*plainchar = state_in->plainchar;
       
    32 	
       
    33 	switch (state_in->step)
       
    34 	{
       
    35 		while (1)
       
    36 		{
       
    37 	case step_a:
       
    38 			do {
       
    39 				if (codechar == code_in+length_in)
       
    40 				{
       
    41 					state_in->step = step_a;
       
    42 					state_in->plainchar = *plainchar;
       
    43 					return plainchar - plaintext_out;
       
    44 				}
       
    45 				fragment = (char)base64_decode_value(*codechar++);
       
    46 			} while (fragment < 0);
       
    47 			*plainchar    = (fragment & 0x03f) << 2;
       
    48 	case step_b:
       
    49 			do {
       
    50 				if (codechar == code_in+length_in)
       
    51 				{
       
    52 					state_in->step = step_b;
       
    53 					state_in->plainchar = *plainchar;
       
    54 					return plainchar - plaintext_out;
       
    55 				}
       
    56 				fragment = (char)base64_decode_value(*codechar++);
       
    57 			} while (fragment < 0);
       
    58 			*plainchar++ |= (fragment & 0x030) >> 4;
       
    59 			*plainchar    = (fragment & 0x00f) << 4;
       
    60 	case step_c:
       
    61 			do {
       
    62 				if (codechar == code_in+length_in)
       
    63 				{
       
    64 					state_in->step = step_c;
       
    65 					state_in->plainchar = *plainchar;
       
    66 					return plainchar - plaintext_out;
       
    67 				}
       
    68 				fragment = (char)base64_decode_value(*codechar++);
       
    69 			} while (fragment < 0);
       
    70 			*plainchar++ |= (fragment & 0x03c) >> 2;
       
    71 			*plainchar    = (fragment & 0x003) << 6;
       
    72 	case step_d:
       
    73 			do {
       
    74 				if (codechar == code_in+length_in)
       
    75 				{
       
    76 					state_in->step = step_d;
       
    77 					state_in->plainchar = *plainchar;
       
    78 					return plainchar - plaintext_out;
       
    79 				}
       
    80 				fragment = (char)base64_decode_value(*codechar++);
       
    81 			} while (fragment < 0);
       
    82 			*plainchar++   |= (fragment & 0x03f);
       
    83 		}
       
    84 	}
       
    85 	/* control should not reach here */
       
    86 	return plainchar - plaintext_out;
       
    87 }
       
    88 
       
    89 /*
       
    90 cencoder.c - c source to a base64 encoding algorithm implementation
       
    91 
       
    92 This is part of the libb64 project, and has been placed in the public domain.
       
    93 For details, see http://sourceforge.net/projects/libb64
       
    94 */
       
    95 
       
    96 const int CHARS_PER_LINE = 72;
       
    97 
       
    98 void base64_init_encodestate(base64_encodestate* state_in)
       
    99 {
       
   100 	state_in->step = step_A;
       
   101 	state_in->result = 0;
       
   102 	state_in->stepcount = 0;
       
   103 }
       
   104 
       
   105 char base64_encode_value(char value_in)
       
   106 {
       
   107 	static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
       
   108 	if (value_in > 63) return '=';
       
   109 	return encoding[(int)value_in];
       
   110 }
       
   111 
       
   112 int base64_encode_block(const uint8_t* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in)
       
   113 {
       
   114 	const uint8_t* plainchar = plaintext_in;
       
   115 	const uint8_t* const plaintextend = plaintext_in + length_in;
       
   116 	char* codechar = code_out;
       
   117 	char result;
       
   118 	uint8_t fragment;
       
   119 	
       
   120 	result = state_in->result;
       
   121 	
       
   122 	switch (state_in->step)
       
   123 	{
       
   124 		while (1)
       
   125 		{
       
   126 	case step_A:
       
   127 			if (plainchar == plaintextend)
       
   128 			{
       
   129 				state_in->result = result;
       
   130 				state_in->step = step_A;
       
   131 				return codechar - code_out;
       
   132 			}
       
   133 			fragment = *plainchar++;
       
   134 			result = (fragment & 0x0fc) >> 2;
       
   135 			*codechar++ = base64_encode_value(result);
       
   136 			result = (fragment & 0x003) << 4;
       
   137 	case step_B:
       
   138 			if (plainchar == plaintextend)
       
   139 			{
       
   140 				state_in->result = result;
       
   141 				state_in->step = step_B;
       
   142 				return codechar - code_out;
       
   143 			}
       
   144 			fragment = *plainchar++;
       
   145 			result |= (fragment & 0x0f0) >> 4;
       
   146 			*codechar++ = base64_encode_value(result);
       
   147 			result = (fragment & 0x00f) << 2;
       
   148 	case step_C:
       
   149 			if (plainchar == plaintextend)
       
   150 			{
       
   151 				state_in->result = result;
       
   152 				state_in->step = step_C;
       
   153 				return codechar - code_out;
       
   154 			}
       
   155 			fragment = *plainchar++;
       
   156 			result |= (fragment & 0x0c0) >> 6;
       
   157 			*codechar++ = base64_encode_value(result);
       
   158 			result  = (fragment & 0x03f) >> 0;
       
   159 			*codechar++ = base64_encode_value(result);
       
   160 			
       
   161 			++(state_in->stepcount);
       
   162 			if (state_in->stepcount == CHARS_PER_LINE/4)
       
   163 			{
       
   164 				*codechar++ = '\n';
       
   165 				state_in->stepcount = 0;
       
   166 			}
       
   167 		}
       
   168 	}
       
   169 	/* control should not reach here */
       
   170 	return codechar - code_out;
       
   171 }
       
   172 
       
   173 int base64_encode_blockend(char* code_out, base64_encodestate* state_in)
       
   174 {
       
   175 	char* codechar = code_out;
       
   176 	
       
   177 	switch (state_in->step)
       
   178 	{
       
   179 	case step_B:
       
   180 		*codechar++ = base64_encode_value(state_in->result);
       
   181 		*codechar++ = '=';
       
   182 		*codechar++ = '=';
       
   183 		break;
       
   184 	case step_C:
       
   185 		*codechar++ = base64_encode_value(state_in->result);
       
   186 		*codechar++ = '=';
       
   187 		break;
       
   188 	case step_A:
       
   189 		break;
       
   190 	}
       
   191 	*codechar++ = '\n';
       
   192 	
       
   193 	return codechar - code_out;
       
   194 }
       
   195 
       
   196 // end of base64.c ...
       
   197