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Add decode_base64_custom BiF to allow alternate base64 alphabets.

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Addresses #670
This commit is contained in:
Jon Siwek 2011-11-11 13:48:11 -06:00
parent 151664bc26
commit 5865bf3850
5 changed files with 97 additions and 14 deletions
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69
src/Base64.cc
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@ -1,14 +1,27 @@
#include "config.h"
#include "Base64.h"
static int base64_table[256];
int Base64Decoder::default_base64_table[256];
const string Base64Decoder::default_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static void init_base64_table()
int* Base64Decoder::InitBase64Table(const string& alphabet)
{
static int table_initialized = 0;
static bool default_table_initialized = false;
if ( ++table_initialized > 1 )
return;
if ( alphabet == default_alphabet && default_table_initialized )
return default_base64_table;
int* base64_table = 0;
if ( alphabet == default_alphabet )
{
base64_table = default_base64_table;
default_table_initialized = true;
}
else
{
base64_table = new int[256];
}
int i;
for ( i = 0; i < 256; ++i )
@ -16,28 +29,44 @@ static void init_base64_table()
for ( i = 0; i < 26; ++i )
{
base64_table['A' + i] = i;
base64_table['a' + i] = i + 26;
base64_table[int(alphabet[0 + i])] = i;
base64_table[int(alphabet[26 + i])] = i + 26;
}
for ( i = 0; i < 10; ++i )
base64_table['0' + i] = i + 52;
base64_table[int(alphabet[52 + i])] = i + 52;
// Casts to avoid compiler warnings.
base64_table[int('+')] = 62;
base64_table[int('/')] = 63;
base64_table[int(alphabet[62])] = 62;
base64_table[int(alphabet[63])] = 63;
base64_table[int('=')] = 0;
return base64_table;
}
Base64Decoder::Base64Decoder(Analyzer* arg_analyzer)
{
init_base64_table();
base64_table = InitBase64Table(default_alphabet);
base64_group_next = 0;
base64_padding = base64_after_padding = 0;
errored = 0;
analyzer = arg_analyzer;
}
Base64Decoder::Base64Decoder(Analyzer* arg_analyzer, const string& alphabet)
{
base64_table = InitBase64Table(alphabet);
base64_group_next = 0;
base64_padding = base64_after_padding = 0;
errored = 0;
analyzer = arg_analyzer;
}
Base64Decoder::~Base64Decoder()
{
if ( base64_table != default_base64_table ) delete base64_table;
}
int Base64Decoder::Decode(int len, const char* data, int* pblen, char** pbuf)
{
int blen;
@ -142,13 +171,21 @@ int Base64Decoder::Done(int* pblen, char** pbuf)
return 0;
}
BroString* decode_base64(const BroString* s)
BroString* decode_base64(const BroString* s, const BroString* a)
{
if (a->Len() != 64)
{
reporter->Error("base64 decoding alphabet is not 64 characters: %s",
a->CheckString());
return 0;
}
int buf_len = int((s->Len() + 3) / 4) * 3 + 1;
int rlen2, rlen = buf_len;
char* rbuf2, *rbuf = new char[rlen];
Base64Decoder dec(0);
Base64Decoder dec(0, a->CheckString());
if ( dec.Decode(s->Len(), (const char*) s->Bytes(), &rlen, &rbuf) == -1 )
goto err;
@ -166,3 +203,9 @@ err:
delete [] rbuf;
return 0;
}
BroString* decode_base64(const BroString* s)
{
BroString a(Base64Decoder::default_alphabet);
return decode_base64(s, &a);
}