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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
/**
*
* $Id$
* This class convert a string to a base64 representation of the string.
*
*/
#include <vespa/vespalib/encoding/base64.h>
#include <vespa/vespalib/util/exceptions.h>
#include <vespa/vespalib/util/stringfmt.h>
#include <cassert>
namespace vespalib {
static const char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/=";
// Set -1 for illegal chars that will cause an error.
// Set -2 for illegal chars that will be ignored. (whitespace " \r\t\f\n")
static const signed char base64Backwards[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -2, -2, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -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, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 };
std::string
Base64::encode(const char* source, int len)
{
// Assign a string that we know is long enough
std::string result(getMaximumEncodeLength(len), '\0');
int outlen = encode(source, len, &result[0], result.size());
assert(outlen >= 0); // Make sure buffer was big enough.
result.resize(outlen);
return result;
}
std::string
Base64::decode(const char* source, int len)
{
std::string result(getMaximumDecodeLength(len), '\0');
int outlen = decode(source, len, &result[0], len);
assert(outlen >= 0);
result.resize(outlen);
return result;
}
int
Base64::encode(const char *inBuffer, int inLen, char *outBuffer, int outBufLen)
{
int i;
int outLen = 0;
for (i = 0; inLen >= 3; inLen -= 3) {
if (outBufLen - outLen < 4) {
return -1;
}
// Do this to keep chars > 127
unsigned char a = inBuffer[i];
unsigned char b = inBuffer[i+1];
unsigned char c = inBuffer[i+2];
i += 3;
outBuffer[outLen ] = base64Chars[ a >> 2 ];
outBuffer[outLen + 1] = base64Chars[ (a << 4 & 0x30) | (b >> 4) ];
outBuffer[outLen + 2] = base64Chars[ (b << 2 & 0x3c) | (c >> 6) ];
outBuffer[outLen + 3] = base64Chars[ c & 0x3f ];
outLen += 4;
}
if (inLen) {
if (outBufLen - outLen < 4) {
return -1;
}
// Do this to keep chars with value>127
unsigned char a = inBuffer[i];
outBuffer[outLen] = base64Chars[ a >> 2 ];
if (inLen == 1) {
outBuffer[outLen + 1] = base64Chars[ (a << 4 & 0x30) ];
outBuffer[outLen + 2] = '=';
} else {
unsigned char b = inBuffer[i + 1];
outBuffer[outLen + 1] = base64Chars[ (a << 4 & 0x30) | (b >> 4) ];
outBuffer[outLen + 2] = base64Chars[ b << 2 & 0x3c ];
}
outBuffer[outLen + 3] = '=';
outLen += 4;
}
if (outLen >= outBufLen)
return -1;
outBuffer[outLen] = '\0';
return outLen;
}
int
Base64::decode(const char* inBuffer, int inLen, char* outBuffer, int outLen)
{
// Read char by char to better support skipping of illegal character.
int readbytes = 0;
int num_valid_chars = 0;
const char* thischar = inBuffer;
signed char curchar;
int curOut = 0;
char tmp = 0;
while( (readbytes++ < inLen) && (*thischar != '\0') && (*thischar != '=')) {
curchar = base64Backwards[ (unsigned int)(*thischar++) ];
if (curchar == -2) {
continue; // Some illegal chars will be skipped.
} else if (curchar == -1) {
// Other illegal characters will generate failure
throw IllegalArgumentException(make_string("Illegal base64 character %u found.",
(unsigned int) *thischar), VESPA_STRLOC);
} else {
// Four bytes from input (eqals three bytes in output)
if (outLen <= curOut) {
return -1;
}
switch( num_valid_chars % 4 ) {
case 0:
tmp = (curchar << 2);
break;
case 1:
outBuffer[curOut++] = tmp | ((curchar >> 4) & 0x03);
tmp = ((curchar & 0xf) << 4);
break;
case 2:
outBuffer[curOut++] = tmp | ((curchar >> 2) & 0x0f);
tmp = ((curchar & 0x03 ) << 6);
break;
case 3:
outBuffer[curOut++] = tmp | curchar;
tmp = 0;
break;
}
num_valid_chars++;
}
}
return curOut;
}
} // namespace vespalib
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