kopia lustrzana https://github.com/PiInTheSky/lora-gateway
120 wiersze
3.2 KiB
C
120 wiersze
3.2 KiB
C
#include <stdint.h>
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#include <stdlib.h>
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static char encoding_table[] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
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'w', 'x', 'y', 'z', '0', '1', '2', '3',
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'4', '5', '6', '7', '8', '9', '+', '/'
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};
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static char *decoding_table = NULL;
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static int mod_table[] = { 0, 2, 1 };
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char *
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base64_encode( const char *data,
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size_t input_length,
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size_t * output_length, char *encoded_data )
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{
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int i, j;
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*output_length = 4 * ( ( input_length + 2 ) / 3 );
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// char *encoded_data = malloc(*output_length);
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// if (encoded_data == NULL) return NULL;
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for ( i = 0, j = 0; i < input_length; )
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{
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uint32_t octet_a = i < input_length ? ( unsigned char ) data[i++] : 0;
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uint32_t octet_b = i < input_length ? ( unsigned char ) data[i++] : 0;
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uint32_t octet_c = i < input_length ? ( unsigned char ) data[i++] : 0;
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uint32_t triple = ( octet_a << 0x10 ) + ( octet_b << 0x08 ) + octet_c;
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encoded_data[j++] = encoding_table[( triple >> 3 * 6 ) & 0x3F];
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encoded_data[j++] = encoding_table[( triple >> 2 * 6 ) & 0x3F];
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encoded_data[j++] = encoding_table[( triple >> 1 * 6 ) & 0x3F];
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encoded_data[j++] = encoding_table[( triple >> 0 * 6 ) & 0x3F];
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}
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for ( i = 0; i < mod_table[input_length % 3]; i++ )
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encoded_data[*output_length - 1 - i] = '=';
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return encoded_data;
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}
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void
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build_decoding_table( )
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{
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int i;
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decoding_table = malloc( 256 );
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for ( i = 0; i < 64; i++ )
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decoding_table[( unsigned char ) encoding_table[i]] = i;
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}
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char *
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base64_decode( const char *data, size_t input_length, size_t * output_length )
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{
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int i, j;
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if ( decoding_table == NULL )
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build_decoding_table( );
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if ( input_length % 4 != 0 )
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return NULL;
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*output_length = input_length / 4 * 3;
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if ( data[input_length - 1] == '=' )
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( *output_length )--;
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if ( data[input_length - 2] == '=' )
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( *output_length )--;
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char *decoded_data = malloc( *output_length );
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if ( decoded_data == NULL )
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return NULL;
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for ( i = 0, j = 0; i < input_length; )
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{
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uint32_t sextet_a =
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data[i] == '=' ? 0 & i++ : decoding_table[( int ) data[i++]];
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uint32_t sextet_b =
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data[i] == '=' ? 0 & i++ : decoding_table[( int ) data[i++]];
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uint32_t sextet_c =
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data[i] == '=' ? 0 & i++ : decoding_table[( int ) data[i++]];
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uint32_t sextet_d =
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data[i] == '=' ? 0 & i++ : decoding_table[( int ) data[i++]];
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uint32_t triple = ( sextet_a << 3 * 6 )
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+ ( sextet_b << 2 * 6 )
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+ ( sextet_c << 1 * 6 ) + ( sextet_d << 0 * 6 );
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if ( j < *output_length )
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decoded_data[j++] = ( triple >> 2 * 8 ) & 0xFF;
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if ( j < *output_length )
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decoded_data[j++] = ( triple >> 1 * 8 ) & 0xFF;
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if ( j < *output_length )
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decoded_data[j++] = ( triple >> 0 * 8 ) & 0xFF;
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}
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return decoded_data;
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}
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void
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base64_cleanup( )
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{
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free( decoding_table );
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}
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