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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 4 -*- */
/* vi: set expandtab shiftwidth=4 tabstop=4: */
/**
* \file
* <PRE>
* High performance base64 encoder / decoder
* Version 1.3 -- 17-Mar-2006
*
* Copyright © 2005, 2006, Nick Galbreath -- nickg [at] modp [dot] com
* All rights reserved.
*
* http://modp.com/release/base64
*
* Released under bsd license. See modp_b64.c for details.
* </pre>
*
* The default implementation is the standard b64 encoding with padding.
* It's easy to change this to use "URL safe" characters and to remove
* padding. See the modp_b64.c source code for details.
*
*/
#ifndef MODP_B64
#define MODP_B64
#ifdef __cplusplus
extern "C" {
#endif
/**
* Encode a raw binary string into base 64.
* src contains the bytes
* len contains the number of bytes in the src
* dest should be allocated by the caller to contain
* at least modp_b64_encode_len(len) bytes (see below)
* This will contain the null-terminated b64 encoded result
* returns length of the destination string plus the ending null byte
* i.e. the result will be equal to strlen(dest) + 1
*
* Example
*
* \code
* char* src = ...;
* int srclen = ...; //the length of number of bytes in src
* char* dest = (char*) malloc(modp_b64_encode_len);
* int len = modp_b64_encode(dest, src, sourcelen);
* if (len == -1) {
* printf("Error\n");
* } else {
* printf("b64 = %s\n", dest);
* }
* \endcode
*
*/
int modp_b64_encode(char* dest, const char* str, int len);
/**
* Decode a base64 encoded string
*
* src should contain exactly len bytes of b64 characters.
* if src contains -any- non-base characters (such as white
* space, -1 is returned.
*
* dest should be allocated by the caller to contain at least
* len * 3 / 4 bytes.
*
* Returns the length (strlen) of the output, or -1 if unable to
* decode
*
* \code
* char* src = ...;
* int srclen = ...; // or if you don't know use strlen(src)
* char* dest = (char*) malloc(modp_b64_decode_len(srclen));
* int len = modp_b64_decode(dest, src, sourcelen);
* if (len == -1) { error }
* \endcode
*/
int modp_b64_decode(char* dest, const char* src, int len);
/**
* Given a source string of length len, this returns the amount of
* memory the destination string should have.
*
* remember, this is integer math
* 3 bytes turn into 4 chars
* ceiling[len / 3] * 4 + 1
*
* +1 is for any extra null.
*/
#define modp_b64_encode_len(A) ((A+2)/3 * 4 + 1)
/**
* Given a base64 string of length len,
* this returns the amount of memory required for output string
* It maybe be more than the actual number of bytes written.
* NOTE: remember this is integer math
* this allocates a bit more memory than traditional versions of b64
* decode 4 chars turn into 3 bytes
* floor[len * 3/4] + 2
*/
#define modp_b64_decode_len(A) (A / 4 * 3 + 2)
/**
* Will return the strlen of the output from encoding.
* This may be less than the required number of bytes allocated.
*
* This allows you to 'deserialized' a struct
* \code
* char* b64encoded = "...";
* int len = strlen(b64encoded);
*
* struct datastuff foo;
* if (modp_b64_encode_strlen(sizeof(struct datastuff)) != len) {
* // wrong size
* return false;
* } else {
* // safe to do;
* if (modp_b64_decode((char*) &foo, b64encoded, len) == -1) {
* // bad characters
* return false;
* }
* }
* // foo is filled out now
* \endcode
*/
#define modp_b64_encode_strlen(A) ((A + 2)/ 3 * 4)
#ifdef __cplusplus
}
#include <string>
inline std::string& modp_b64_encode(std::string& s)
{
std::string x(modp_b64_encode_len(s.size()), '\0');
int d = modp_b64_encode(const_cast<char*>(x.data()), s.data(), s.size());
x.erase(d, std::string::npos);
s.swap(x);
return s;
}
/**
* base 64 decode a string (self-modifing)
* On failure, the string is empty.
*
* This function is for C++ only (duh)
*
* \param[in,out] s the string to be decoded
* \return a reference to the input string
*/
inline std::string& modp_b64_decode(std::string& s)
{
std::string x(modp_b64_decode_len(s.size()), '\0');
int d = modp_b64_decode(const_cast<char*>(x.data()), s.data(), s.size());
if (d < 0) {
x.clear();
} else {
x.erase(d, std::string::npos);
}
s.swap(x);
return s;
}
#endif /* __cplusplus */
#endif /* MODP_B64 */
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