mirror of
https://github.com/owntracks/recorder.git
synced 2024-11-16 02:18:27 -07:00
120 lines
2.3 KiB
C
Executable File
120 lines
2.3 KiB
C
Executable File
/*
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This code is public domain software.
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*/
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#include "base64.h"
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#include <stdlib.h>
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#include <string.h>
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// base64 encoding
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//
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// buf: binary input data
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// size: size of input (bytes)
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// return: base64-encoded string (null-terminated)
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// memory for output will be allocated here, free it later
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//
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char* base64_encode(const void* buf, size_t size)
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{
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static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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char* str = (char*) malloc((size+3)*4/3 + 1);
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char* p = str;
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const unsigned char* q = (const unsigned char*) buf;
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size_t i = 0;
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while (i < size) {
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int c = q[i++];
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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c *= 256;
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if (i < size)
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c += q[i];
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i++;
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*p++ = base64[(c & 0x00fc0000) >> 18];
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*p++ = base64[(c & 0x0003f000) >> 12];
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if (i > size + 1)
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*p++ = '=';
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else
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*p++ = base64[(c & 0x00000fc0) >> 6];
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if (i > size)
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*p++ = '=';
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else
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*p++ = base64[c & 0x0000003f];
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}
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*p = 0;
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return str;
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}
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// single base64 character conversion
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//
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static int POS(char c)
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{
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if (c>='A' && c<='Z') return c - 'A';
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if (c>='a' && c<='z') return c - 'a' + 26;
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if (c>='0' && c<='9') return c - '0' + 52;
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if (c == '+') return 62;
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if (c == '/') return 63;
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if (c == '=') return -1;
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return -2;
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}
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// base64 decoding
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//
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// s: base64 string, must be null-terminated
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// data: output buffer for decoded data
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// data_len size of decoded data
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// return: allocated data buffer
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//
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void* base64_decode(const char* s, size_t *data_len)
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{
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const char *p;
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unsigned char *q, *data;
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int n[4];
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size_t len = strlen(s);
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if (len % 4)
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return NULL;
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data = (unsigned char*) malloc(len/4*3);
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q = (unsigned char*) data;
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for (p = s; *p; ) {
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n[0] = POS(*p++);
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n[1] = POS(*p++);
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n[2] = POS(*p++);
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n[3] = POS(*p++);
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if (n[0] == -2 || n[1] == -2 || n[2] == -2 || n[3] == -2)
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return NULL;
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if (n[0] == -1 || n[1] == -1)
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return NULL;
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if (n[2] == -1 && n[3] != -1)
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return NULL;
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q[0] = (n[0] << 2) + (n[1] >> 4);
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if (n[2] != -1)
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q[1] = ((n[1] & 15) << 4) + (n[2] >> 2);
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if (n[3] != -1)
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q[2] = ((n[2] & 3) << 6) + n[3];
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q += 3;
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}
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*data_len = q-data - (n[2]==-1) - (n[3]==-1);
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return data;
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}
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