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127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
/*
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* Base64 encode/decode functions used in sxmp
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* openssl stuff wasn't used to avoid additional memleaks and allocation,
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* deallocation of BIO and to avoid dependency, since not only openssl
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* might be in use
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*
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* (c) Alexander Vdolainen 2016 <avdolainen@zoho.com>
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*
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* libsxmp is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* libsxmp is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.";
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sxt/base64.h>
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static const char b64[]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static inline void encodeblock(unsigned char *in, unsigned char *out, int len)
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{
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out[0] = (unsigned char) b64[ (int)(in[0] >> 2) ];
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out[1] = (unsigned char) b64[ (int)(((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4)) ];
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out[2] = (unsigned char) (len > 1 ? b64[ (int)(((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6)) ] : '=');
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out[3] = (unsigned char) (len > 2 ? b64[ (int)(in[2] & 0x3f) ] : '=');
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}
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static inline char __block(char b)
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{
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const char *j = strchr(b64, b);
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if(j) return j - b64;
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else return 0;
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}
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static inline void decodeblock(unsigned char *in, unsigned char *out)
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{
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char a = __block(in[0]);
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char b = __block(in[1]);
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char c = __block(in[2]);
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char d = __block(in[3]);
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out[0] = (unsigned char) (a << 2 | b >> 4);
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out[1] = (unsigned char) (b << 4 | c >> 2);
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out[2] = (unsigned char) (((c << 6) & 0xc0) | d);
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}
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size_t sxt_rawlen2b64len(size_t raw_length)
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{
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return (size_t)(((4 * raw_length / 3) + 3) & ~3);
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}
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size_t sxt_b64encode_in(const char *data, char *bdata, size_t data_len)
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{
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size_t bdata_len = 0, c = 0, n = 0;
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int len = 0, nil = 0, i;
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unsigned char ib[4];
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if(!bdata) return -1;
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if(!data || !data_len) return -1;
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else bdata_len = sxt_rawlen2b64len(data_len);
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while(n != bdata_len) {
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if((c + 3) <= data_len) {
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len = 3;
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encodeblock((unsigned char *)data + c, (unsigned char *)bdata + n, len);
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n += 4; c += 3;
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} else {
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nil = (c + 3) - data_len;
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len = 0;
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for(i = 0; i < 3; i++) {
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if(i < nil + 1) {
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ib[i] = *((unsigned char *)data + (c + i));
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len++;
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} else ib[i] = (unsigned char)0;
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}
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encodeblock(ib, (unsigned char *)bdata + n, len);
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break;
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}
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}
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return bdata_len;
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}
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char *sxt_b64encode(const char *data, size_t data_len)
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{
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char *bdata = NULL;
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size_t bdata_len = 0;
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if(!data || !data_len) return NULL;
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else bdata_len = sxt_rawlen2b64len(data_len);
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if(!(bdata = malloc(bdata_len))) return NULL;
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sxt_b64encode_in(data, bdata, data_len);
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return bdata;
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}
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size_t sxt_b64decode_in(const char *idata, size_t idata_len, char *data, size_t data_len)
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{
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size_t enc = 0, dec = 0;
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if(!idata || !idata_len) return -1;
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if(!data || !data_len) return -1;
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for(enc = 0; enc != idata_len; enc += 4) {
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if(dec >= data_len) return dec;
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decodeblock((unsigned char *)idata + enc, (unsigned char *)data + dec);
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dec += 3;
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}
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return dec;
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}
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