base64.h File Reference

Base64 encoding. More...

#include <stdint.h>
#include <string.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static size_t	base64_encoded_len (size_t raw_len)
	Calculate length of base64-encoded data. More...
static size_t	base64_decoded_max_len (const char *encoded)
	Calculate maximum length of base64-decoded string. More...
size_t	base64_encode (const void *raw, size_t raw_len, char *data, size_t len)
	Base64-encode data. More...
int	base64_decode (const char *encoded, void *data, size_t len)
	Base64-decode string. More...

Detailed Description

Base64 encoding.

Definition in file base64.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

base64_encoded_len()

static size_t base64_encoded_len ( size_t  raw_len )

inlinestatic

Calculate length of base64-encoded data.

Parameters

raw_len

Raw data length

Return values

encoded_len

Encoded string length (excluding NUL)

Definition at line 21 of file base64.h.

                                                           {
        return ( ( ( raw_len + 3 - 1 ) / 3 ) * 4 );
}

References raw_len.

Referenced by base64_encode_okx(), http_format_ntlm_auth(), icert_encode(), ocsp_uri_string(), and validator_start_download().

base64_decoded_max_len()

static size_t base64_decoded_max_len ( const char *  encoded )

inlinestatic

Calculate maximum length of base64-decoded string.

Parameters

encoded	Encoded string
max_raw_len	Maximum length of raw data

Note that the exact length of the raw data cannot be known until the string is decoded.

Definition at line 34 of file base64.h.

                                                                    {
        return ( ( ( strlen ( encoded ) + 4 - 1 ) / 4 ) * 3 );
}

References strlen().

Referenced by base64_decode_okx(), ipair_rx_pubkey(), and pem_asn1().

base64_encode()

size_t base64_encode	(	const void *	raw,
		size_t	raw_len,
		char *	data,
		size_t	len
	)

Base64-encode data.

Parameters

raw	Raw data
raw_len	Length of raw data
data	Buffer
len	Length of buffer

Return values

len	Encoded length

Definition at line 51 of file base64.c.

                                    {
        const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
        size_t raw_bit_len = ( 8 * raw_len );
        size_t used = 0;
        unsigned int bit;
        unsigned int byte;
        unsigned int shift;
        unsigned int tmp;

        for ( bit = 0 ; bit < raw_bit_len ; bit += 6, used++ ) {
                byte = ( bit / 8 );
                shift = ( bit % 8 );
                tmp = ( raw_bytes[byte] << shift );
                if ( ( byte + 1 ) < raw_len )
                        tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) );
                tmp = ( ( tmp >> 2 ) & 0x3f );
                if ( used < len )
                        data[used] = base64[tmp];
        }
        for ( ; ( bit % 8 ) != 0 ; bit += 6, used++ ) {
                if ( used < len )
                        data[used] = '=';
        }
        if ( used < len )
                data[used] = '\0';
        if ( len )
                data[ len - 1 ] = '\0'; /* Ensure terminator exists */

        return used;
}

References base64, bit, data, len, raw, raw_len, and tmp.

Referenced by base64_encode_okx(), format_base64_setting(), http_format_basic_auth(), http_format_ntlm_auth(), icert_encode(), ocsp_uri_string(), and validator_start_download().

base64_decode()

int base64_decode	(	const char *	encoded,
		void *	data,
		size_t	len
	)

Base64-decode string.

Parameters

encoded	Encoded string
data	Buffer
len	Length of buffer

Return values

len	Length of data, or negative error

Definition at line 91 of file base64.c.

                                                                  {
        const char *in = encoded;
        uint8_t *out = data;
        uint8_t in_char;
        char *match;
        int in_bits;
        unsigned int bit = 0;
        unsigned int pad_count = 0;
        size_t offset;

        /* Zero the output buffer */
        memset ( data, 0, len );

        /* Decode string */
        while ( ( in_char = *(in++) ) ) {

                /* Ignore whitespace characters */
                if ( isspace ( in_char ) )
                        continue;

                /* Process pad characters */
                if ( in_char == '=' ) {
                        if ( pad_count >= 2 ) {
                                DBG ( "Base64-encoded string \"%s\" has too "
                                      "many pad characters\n", encoded );
                                return -EINVAL;
                        }
                        pad_count++;
                        bit -= 2; /* unused_bits = ( 2 * pad_count ) */
                        continue;
                }
                if ( pad_count ) {
                        DBG ( "Base64-encoded string \"%s\" has invalid pad "
                              "sequence\n", encoded );
                        return -EINVAL;
                }

                /* Process normal characters */
                match = strchr ( base64, in_char );
                if ( ! match ) {
                        DBG ( "Base64-encoded string \"%s\" contains invalid "
                              "character '%c'\n", encoded, in_char );
                        return -EINVAL;
                }
                in_bits = ( match - base64 );

                /* Add to raw data */
                in_bits <<= 2;
                offset = ( bit / 8 );
                if ( offset < len )
                        out[offset] |= ( in_bits >> ( bit % 8 ) );
                offset++;
                if ( offset < len )
                        out[offset] |= ( in_bits << ( 8 - ( bit % 8 ) ) );
                bit += 6;
        }

        /* Check that we decoded a whole number of bytes */
        if ( ( bit % 8 ) != 0 ) {
                DBG ( "Base64-encoded string \"%s\" has invalid bit length "
                      "%d\n", encoded, bit );
                return -EINVAL;
        }

        /* Return length in bytes */
        return ( bit / 8 );
}

References base64, bit, data, DBG, EINVAL, in, isspace(), len, memset(), offset, out, and strchr().

Referenced by base64_decode_okx(), http_parse_ntlm_auth(), ipair_rx_pubkey(), iscsi_large_binary_decode(), parse_base64_setting(), and pem_asn1().