First public release
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ben
253
src/base64.c
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253
src/base64.c
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/*
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* Base64 encoding/decoding (RFC1341)
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* Copyright (c) 2005-2011, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include "base64.h"
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static const unsigned char base64_table[65] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/**
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* base64_encode - Base64 encode
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* @src: Data to be encoded
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* @len: Length of the data to be encoded
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* @out_len: Pointer to output length variable, or %NULL if not used
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* Returns: Allocated buffer of out_len bytes of encoded data,
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* or %NULL on failure
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*
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* Caller is responsible for freeing the returned buffer. Returned buffer is
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* nul terminated to make it easier to use as a C string. The nul terminator is
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* not included in out_len.
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*/
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unsigned char * base64_encode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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unsigned char *out, *pos;
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const unsigned char *end, *in;
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size_t olen;
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int line_len;
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olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
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olen += olen / 76; /* line feeds */
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olen++; /* nul termination */
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if (olen < len)
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return NULL; /* integer overflow */
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out = malloc(olen);
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if (out == NULL)
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return NULL;
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end = src + len;
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in = src;
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pos = out;
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line_len = 0;
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while (end - in >= 3) {
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*pos++ = base64_table[in[0] >> 2];
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*pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
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*pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
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*pos++ = base64_table[in[2] & 0x3f];
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in += 3;
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line_len += 4;
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if (line_len >= 76) {
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*pos++ = '\n';
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line_len = 0;
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}
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}
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if (end - in) {
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*pos++ = base64_table[in[0] >> 2];
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if (end - in == 1) {
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*pos++ = base64_table[(in[0] & 0x03) << 4];
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*pos++ = '=';
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} else {
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*pos++ = base64_table[((in[0] & 0x03) << 4) |
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(in[1] >> 4)];
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*pos++ = base64_table[(in[1] & 0x0f) << 2];
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}
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*pos++ = '=';
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line_len += 4;
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}
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if (line_len)
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*pos++ = '\n';
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*pos = '\0';
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if (out_len)
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*out_len = pos - out;
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return out;
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}
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/**
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* base64_decode - Base64 decode
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* @src: Data to be decoded
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* @len: Length of the data to be decoded
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* @out_len: Pointer to output length variable
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* Returns: Allocated buffer of out_len bytes of decoded data,
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* or %NULL on failure
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*
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* Caller is responsible for freeing the returned buffer.
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*/
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unsigned char * base64_decode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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unsigned char dtable[256], *out, *pos, block[4], tmp;
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size_t i, count, olen;
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int pad = 0;
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memset(dtable, 0x80, 256);
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for (i = 0; i < sizeof(base64_table) - 1; i++)
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dtable[base64_table[i]] = (unsigned char) i;
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dtable['='] = 0;
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count = 0;
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for (i = 0; i < len; i++) {
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if (dtable[src[i]] != 0x80)
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count++;
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}
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if (count == 0 || count % 4)
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return NULL;
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olen = count / 4 * 3;
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pos = out = malloc(olen);
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if (out == NULL)
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return NULL;
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count = 0;
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for (i = 0; i < len; i++) {
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tmp = dtable[src[i]];
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if (tmp == 0x80)
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continue;
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if (src[i] == '=')
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pad++;
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block[count] = tmp;
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count++;
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if (count == 4) {
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*pos++ = (block[0] << 2) | (block[1] >> 4);
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*pos++ = (block[1] << 4) | (block[2] >> 2);
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*pos++ = (block[2] << 6) | block[3];
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count = 0;
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if (pad) {
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if (pad == 1)
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pos--;
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else if (pad == 2)
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pos -= 2;
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else {
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/* Invalid padding */
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free(out);
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return NULL;
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}
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break;
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}
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}
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}
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*out_len = pos - out;
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return out;
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}
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unsigned char * b64t_encode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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// allocate new buffer
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unsigned char *out = malloc(len);
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if (out == NULL)
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return NULL;
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memset(out, 0, len);
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// remove new line
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size_t index = 0;
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size_t new_index = 0;
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for (index =0; index < len; index++)
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{
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if(src[index] != '\n' &&
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src[index] != '\r' &&
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src[index] != '=' &&
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src[index] >= '+' &&
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src[index] <= 'z' ) {
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out[new_index] = src[index];
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new_index ++;
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}
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}
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out[new_index] = 0;
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*out_len = new_index;
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for (size_t i=0; i < *out_len; i++) {
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if(out[i] == '+') {
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out[i] = '-';
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}
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}
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for (size_t i=0; i < *out_len; i++) {
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if(out[i] == '/') {
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out[i] = '_';
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}
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}
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return out;
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}
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unsigned char * b64t_decode(const unsigned char *src, size_t len,
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size_t *out_len)
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{
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size_t index = 0;
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size_t nb_encoding_chars = 0;
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for (index=0; index < len; index++) {
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if(src[index] == '\n' ||
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src[index] == '\r' ||
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src[index] == '=') {
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nb_encoding_chars++;
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}
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}
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size_t new_len = len - nb_encoding_chars;
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size_t nb_newlines = new_len / 76;
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size_t padding_len = 0;
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if (new_len % 4 != 0) {
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padding_len = 4 - new_len % 4;
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}
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*out_len = new_len + nb_newlines + padding_len + 1;
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// allocate new buffer
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unsigned char *out = malloc(*out_len);
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if (out == NULL)
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return NULL;
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memset(out, 0, len);
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size_t index_out = 0;
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size_t index_data = 0;
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for(index = 0; index < len; index++) {
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if(src[index] != '\n' &&
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src[index] != '\r' &&
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src[index] != '=') {
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if(index_data != 0 && index_data % 76 == 0) {
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out[index_out] = '\n';
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index_out++;
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}
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if (src[index] == '-') {
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out[index_out] = '+';
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}
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else if (src[index] == '_') {
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out[index_out] = '/';
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}
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else {
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out[index_out] = src[index];
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}
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index_out++;
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index_data++;
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}
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}
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for(index = 0; index < padding_len; index ++) {
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out[index_out] = '=';
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index_out++;
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}
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out[index_out] = '\n';
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return out;
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}
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