114 lines
2.2 KiB
C
114 lines
2.2 KiB
C
/*
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base64.c - by Joe DF (joedf@ahkscript.org)
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Released under the MIT License
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See "base64.h", for more information.
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Thank you for inspiration:
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http://www.codeproject.com/Tips/813146/Fast-base-functions-for-encode-decode
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*/
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#include "base64.h"
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//Base64 char table - used internally for encoding
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unsigned char b64_chr[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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unsigned int b64_int(unsigned int ch) {
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// ASCII to base64_int
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// 65-90 Upper Case >> 0-25
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// 97-122 Lower Case >> 26-51
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// 48-57 Numbers >> 52-61
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// 43 Plus (+) >> 62
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// 47 Slash (/) >> 63
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// 61 Equal (=) >> 64~
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if (ch==43)
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return 62;
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if (ch==47)
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return 63;
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if (ch==61)
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return 64;
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if ((ch>47) && (ch<58))
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return ch + 4;
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if ((ch>64) && (ch<91))
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return ch - 'A';
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if ((ch>96) && (ch<123))
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return (ch - 'a') + 26;
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return 0;
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}
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unsigned int b64e_size(unsigned int in_size) {
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// size equals 4*floor((1/3)*(in_size+2));
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int i, j = 0;
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for (i=0;i<in_size;i++) {
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if (i % 3 == 0)
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j += 1;
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}
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return (4*j);
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}
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unsigned int b64d_size(unsigned int in_size) {
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return ((3*in_size)/4);
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}
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unsigned int
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b64_encode(char* in, unsigned int in_len, char* out){
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unsigned int i=0, j=0, k=0, s[3];
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for (i=0;i<in_len;i++){
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s[j++]=*(in+i);
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if (j==3){
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out[k+0] = b64_chr[ (s[0]&255)>>2 ];
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out[k+1] = b64_chr[ ((s[0]&0x03)<<4)+((s[1]&0xF0)>>4) ];
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out[k+2] = b64_chr[ ((s[1]&0x0F)<<2)+((s[2]&0xC0)>>6) ];
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out[k+3] = b64_chr[ s[2]&0x3F ];
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j=0; k+=4;
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}
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}
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if (j) {
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if (j==1)
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s[1] = 0;
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out[k+0] = b64_chr[ (s[0]&255)>>2 ];
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out[k+1] = b64_chr[ ((s[0]&0x03)<<4)+((s[1]&0xF0)>>4) ];
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if (j==2)
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out[k+2] = b64_chr[ ((s[1]&0x0F)<<2) ];
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else
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out[k+2] = '=';
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out[k+3] = '=';
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k+=4;
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}
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out[k] = '\0';
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return k;
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}
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int
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b64_decode(char* in, unsigned int in_len, char* out){
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unsigned int i=0, j=0, k=0, s[4];
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for (i=0;i<in_len;i++) {
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s[j++]=b64_int(*(in+i));
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if (j==4) {
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out[k+0] = ((s[0]&255)<<2)+((s[1]&0x30)>>4);
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if (s[2]!=64) {
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out[k+1] = ((s[1]&0x0F)<<4)+((s[2]&0x3C)>>2);
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if ((s[3]!=64)) {
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out[k+2] = ((s[2]&0x03)<<6)+(s[3]); k+=3;
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} else {
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k+=2;
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}
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} else {
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k+=1;
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}
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j=0;
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}
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}
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return k;
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}
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