172 lines
4.4 KiB
C++
172 lines
4.4 KiB
C++
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 4 -*- */
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/* vi: set expandtab shiftwidth=4 tabstop=4: */
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/**
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* \file
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* <PRE>
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* High performance base64 encoder / decoder
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* Version 1.3 -- 17-Mar-2006
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*
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* Copyright © 2005, 2006, Nick Galbreath -- nickg [at] modp [dot] com
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* All rights reserved.
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*
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* http://modp.com/release/base64
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*
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* Released under bsd license. See modp_b64.c for details.
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* </pre>
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*
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* The default implementation is the standard b64 encoding with padding.
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* It's easy to change this to use "URL safe" characters and to remove
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* padding. See the modp_b64.c source code for details.
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*
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*/
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#ifndef MODP_B64
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#define MODP_B64
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Encode a raw binary string into base 64.
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* src contains the bytes
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* len contains the number of bytes in the src
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* dest should be allocated by the caller to contain
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* at least modp_b64_encode_len(len) bytes (see below)
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* This will contain the null-terminated b64 encoded result
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* returns length of the destination string plus the ending null byte
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* i.e. the result will be equal to strlen(dest) + 1
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*
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* Example
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*
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* \code
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* char* src = ...;
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* int srclen = ...; //the length of number of bytes in src
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* char* dest = (char*) malloc(modp_b64_encode_len);
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* int len = modp_b64_encode(dest, src, sourcelen);
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* if (len == -1) {
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* printf("Error\n");
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* } else {
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* printf("b64 = %s\n", dest);
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* }
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* \endcode
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*
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*/
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size_t modp_b64_encode(char* dest, const char* str, size_t len);
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/**
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* Decode a base64 encoded string
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*
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* src should contain exactly len bytes of b64 characters.
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* if src contains -any- non-base characters (such as white
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* space, -1 is returned.
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*
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* dest should be allocated by the caller to contain at least
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* len * 3 / 4 bytes.
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*
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* Returns the length (strlen) of the output, or -1 if unable to
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* decode
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*
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* \code
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* char* src = ...;
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* int srclen = ...; // or if you don't know use strlen(src)
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* char* dest = (char*) malloc(modp_b64_decode_len(srclen));
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* int len = modp_b64_decode(dest, src, sourcelen);
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* if (len == -1) { error }
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* \endcode
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*/
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size_t modp_b64_decode(char* dest, const char* src, size_t len);
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/**
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* Given a source string of length len, this returns the amount of
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* memory the destination string should have.
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*
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* remember, this is integer math
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* 3 bytes turn into 4 chars
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* ceiling[len / 3] * 4 + 1
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*
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* +1 is for any extra null.
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*/
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#define modp_b64_encode_len(A) ((A+2)/3 * 4 + 1)
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/**
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* Given a base64 string of length len,
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* this returns the amount of memory required for output string
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* It maybe be more than the actual number of bytes written.
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* NOTE: remember this is integer math
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* this allocates a bit more memory than traditional versions of b64
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* decode 4 chars turn into 3 bytes
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* floor[len * 3/4] + 2
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*/
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#define modp_b64_decode_len(A) (A / 4 * 3 + 2)
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/**
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* Will return the strlen of the output from encoding.
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* This may be less than the required number of bytes allocated.
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*
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* This allows you to 'deserialized' a struct
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* \code
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* char* b64encoded = "...";
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* int len = strlen(b64encoded);
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*
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* struct datastuff foo;
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* if (modp_b64_encode_strlen(sizeof(struct datastuff)) != len) {
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* // wrong size
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* return false;
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* } else {
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* // safe to do;
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* if (modp_b64_decode((char*) &foo, b64encoded, len) == -1) {
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* // bad characters
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* return false;
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* }
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* }
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* // foo is filled out now
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* \endcode
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*/
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#define modp_b64_encode_strlen(A) ((A + 2)/ 3 * 4)
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#define MODP_B64_ERROR ((size_t)-1)
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#ifdef __cplusplus
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}
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#include <string>
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inline std::string& modp_b64_encode(std::string& s)
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{
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std::string x(modp_b64_encode_len(s.size()), '\0');
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size_t d = modp_b64_encode(const_cast<char*>(x.data()), s.data(), (int)s.size());
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x.erase(d, std::string::npos);
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s.swap(x);
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return s;
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}
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/**
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* base 64 decode a string (self-modifing)
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* On failure, the string is empty.
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*
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* This function is for C++ only (duh)
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*
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* \param[in,out] s the string to be decoded
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* \return a reference to the input string
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*/
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inline std::string& modp_b64_decode(std::string& s)
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{
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std::string x(modp_b64_decode_len(s.size()), '\0');
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size_t d = modp_b64_decode(const_cast<char*>(x.data()), s.data(), (int)s.size());
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if (d == MODP_B64_ERROR) {
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x.clear();
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} else {
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x.erase(d, std::string::npos);
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}
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s.swap(x);
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return s;
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}
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#endif /* __cplusplus */
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#endif /* MODP_B64 */
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