mirror of git://git.psyced.org/git/psyced
103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
// $Id: base64.c,v 1.7 2005/11/13 19:52:44 lynx Exp $ // vim:syntax=lpc
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//
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// base64 encoder/decoder
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// 2004 - Dan@Gueldenland - df@erinye.com
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//
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#include <net.h>
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volatile string * char64 = efun::explode("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", "");
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volatile mapping deco64 = funcall( (:
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mapping x = ([ ]);
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int i;
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for(i=0; i<64; ++i) {
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x[char64[i][0]] = i+1;
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}
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x['='] = 1;
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return x;
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:) );
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static int deco(int i) {
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i = deco64[i];
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if(!i) raise_error("Oh crap.\n");
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return i-1;
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}
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string encode_base64(int * b) {
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int bbb, i=0, s=sizeof(b);
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string res = "";
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while(i+3 <= s) {
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bbb = (b[i++] & 0xff) << 16;
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bbb |= (b[i++] & 0xff) << 8;
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bbb |= b[i++] & 0xff;
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res += char64[(bbb & 0xfc0000) >> 18] + char64[(bbb & 0x3f000) >> 12] + char64[(bbb & 0xfc0) >> 6] + char64[bbb & 0x3f];
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}
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if(s - i == 2) {
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bbb = ((b[i++] & 0xff) << 16) | ((b[i++] & 0xff) << 8);
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res += char64[(bbb & 0xfc0000) >> 18] + char64[(bbb & 0x3f000) >> 12] + char64[(bbb & 0xfc0) >> 6] + "=";
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} else if(s - i == 1) {
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bbb = ((b[i] & 0xff) << 16);
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res += char64[(bbb & 0xfc0000) >> 18] + char64[(bbb & 0x3f000) >> 12] + "==";
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}
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return res;
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}
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// this doesn't really enforce base64, but if it finds = on positions they
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// shouldn't be on, this'll get sullen.
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int * decode_base64(string b) {
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int * res = ({ });
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int i=0, s, next;
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b = replace(b, "\n", "");
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b = replace(b, "\r", "");
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s = strlen(b);
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while(i+4 <= s) {
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res += ({ (deco(b[i]) << 2) | (deco(b[i+1]) >> 4) });
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next = ((deco(b[i+1]) << 4) & 0xff) | (deco(b[i+2]) >> 2);
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unless (!next && b[i+2] == '=') {
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res += ({ next });
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} else {
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return res;
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}
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next = ((deco(b[i+2]) << 6) & 0xc0) | deco(b[i+3]);
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unless (!next && b[i+3] == '=') {
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res += ({ next });
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} else {
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return res;
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}
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i += 4;
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}
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return res;
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}
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#if DEBUG > 1
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void base64_self_test() {
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int i, j, cool;
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string x, y, z;
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for(i=0; i<10; ++i) {
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x = "";
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j = random(100) + 5;
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while(j>0) {
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x += to_string(({ 32 + random(96) }));
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--j;
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}
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y = encode_base64(to_array(x));
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z = to_string(decode_base64(y));
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if(z == x) ++cool;
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else {
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P2(("uncool:\n%O !=\n%O\n", x, z));
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P3(("base: %O\n", y))
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P3(("strlen: %O, %O, last: %O\n", strlen(x), strlen(z), z[<1]))
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}
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}
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P2(("base64_self_test: %d out of 10 successful.\n", cool));
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}
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#endif
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