aacf2324c7
atob() has been replaced with a lookup table, removing previous conditionals and function calls necessary to decode.
107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
#include "encode.h"
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#define PADDING '='
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static
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unsigned char b64toascii[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
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"abcdefghijklmnopqrstuvwxyz" \
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"0123456789" \
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"+/";
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static
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unsigned char b64urltoascii[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
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"abcdefghijklmnopqrstuvwxyz" \
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"0123456789" \
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"-_";
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static
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unsigned char asciitob64[] = {
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 62, 0, 62, 0, 63, 52, 53,
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54, 55, 56, 57, 58, 59, 60, 61, 0, 0,
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0, 0, 0, 0, 0, 0, 1, 2, 3, 4,
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5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
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25, 0, 0, 0, 0, 63, 0, 26, 27, 28,
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29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
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39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
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49, 50, 51
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};
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int
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encode(unsigned char *op, int olen, unsigned char *sp, int url)
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{
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int tmp;
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unsigned char *table;
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unsigned char *sbeg;
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unsigned char *tend;
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table = (!url) ? b64toascii : b64urltoascii;
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sbeg = sp;
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tend = op + olen - (olen % 3);
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while (op < tend) {
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*sp++ = table[(*op & ~3) >> 2];
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tmp = (*op++ & 3) << 4;
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*sp++ = table[tmp + ((*op & ~15) >> 4)];
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tmp = (*op++ & 15) << 2;
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*sp++ = table[tmp + ((*op & 192) >> 6)];
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*sp++ = table[*op++ & ~192];
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}
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switch (olen % 3) {
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case 2:
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*sp++ = table[(*op & ~3) >> 2];
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tmp = (*op++ & 3) << 4;
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*sp++ = table[tmp + ((*op & ~15) >> 4)];
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*sp++ = table[(*op & 15) << 2];
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*sp++ = PADDING;
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break;
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case 1:
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*sp++ = table[(*op & ~3) >> 2];
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*sp++ = table[(*op & 3) << 4];
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*sp++ = PADDING;
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*sp++ = PADDING;
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break;
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}
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return sp-sbeg;
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}
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int
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decode(unsigned char *sp, int slen, unsigned char *op)
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{
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int tmp, b;
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unsigned char *obeg;
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unsigned char *qend;
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obeg = op;
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qend = sp + slen - (slen % 4);
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while (sp < qend) {
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tmp = asciitob64[*sp++] << 2;
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b = asciitob64[*sp++];
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*op++ = tmp + ((b & ~15) >> 4);
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tmp = (b & 15) << 4;
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b = asciitob64[*sp++];
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*op++ = tmp + ((b & ~3) >> 2);
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*op++ = ((b & 3) << 6) + asciitob64[*sp++];
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}
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switch (slen % 4) {
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case 3:
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tmp = asciitob64[*sp++] << 2;
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b = asciitob64[*sp++];
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*op++ = tmp + ((b & ~15) >> 4);
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tmp = (b & 15) << 4;
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*op++ = tmp + ((asciitob64[*sp++] & ~3) >> 2);
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break;
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case 2:
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tmp = asciitob64[*sp++] << 2;
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*op++ = tmp + ((asciitob64[*sp++] & ~15) >> 4);
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break;
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}
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return op-obeg;
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}
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