128 lines
2.9 KiB
C++
128 lines
2.9 KiB
C++
#include "base64.h"
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#include <string.h>
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static const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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size_t b64_encoded_size(size_t inlen) {
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size_t ret;
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ret = inlen;
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if (inlen % 3 != 0)
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ret += 3 - (inlen % 3);
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ret /= 3;
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ret *= 4;
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return ret;
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}
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char *b64_encode(const uint8_t *in, size_t len) {
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char *out;
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size_t elen;
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size_t i;
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size_t j;
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size_t v;
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if (in == NULL || len == 0)
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return NULL;
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elen = b64_encoded_size(len);
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out = (char *) malloc(elen + 1);
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out[elen] = '\0';
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for (i = 0, j = 0; i < len; i += 3, j += 4) {
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v = in[i];
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v = i + 1 < len ? v << 8 | in[i + 1] : v << 8;
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v = i + 2 < len ? v << 8 | in[i + 2] : v << 8;
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out[j] = b64chars[(v >> 18) & 0x3F];
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out[j + 1] = b64chars[(v >> 12) & 0x3F];
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if (i + 1 < len) {
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out[j + 2] = b64chars[(v >> 6) & 0x3F];
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} else {
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out[j + 2] = '=';
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}
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if (i + 2 < len) {
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out[j + 3] = b64chars[v & 0x3F];
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} else {
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out[j + 3] = '=';
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}
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}
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return out;
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}
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size_t b64_decoded_size(const char *in) {
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size_t len;
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size_t ret;
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size_t i;
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if (in == NULL)
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return 0;
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len = strlen(in);
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ret = len / 4 * 3;
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for (i = len; i-- > 0;) {
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if (in[i] == '=') {
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ret--;
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} else {
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break;
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}
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}
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return ret;
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}
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static const int b64invs[] = {
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62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3,
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4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51};
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static int b64_isvalidchar(char c) {
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if (c >= '0' && c <= '9')
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return 1;
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if (c >= 'A' && c <= 'Z')
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return 1;
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if (c >= 'a' && c <= 'z')
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return 1;
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if (c == '+' || c == '/' || c == '=')
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return 1;
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return 0;
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}
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int b64_decode(const char *in, uint8_t *out, size_t outlen) {
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size_t len;
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size_t i;
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size_t j;
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int v;
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if (in == NULL || out == NULL)
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return 0;
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len = strlen(in);
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if (outlen < b64_decoded_size(in) || len % 4 != 0)
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return 0;
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for (i = 0; i < len; i++) {
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if (!b64_isvalidchar(in[i])) {
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return 0;
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}
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}
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for (i = 0, j = 0; i < len; i += 4, j += 3) {
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v = b64invs[in[i] - 43];
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v = (v << 6) | b64invs[in[i + 1] - 43];
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v = in[i + 2] == '=' ? v << 6 : (v << 6) | b64invs[in[i + 2] - 43];
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v = in[i + 3] == '=' ? v << 6 : (v << 6) | b64invs[in[i + 3] - 43];
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out[j] = (v >> 16) & 0xFF;
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if (in[i + 2] != '=')
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out[j + 1] = (v >> 8) & 0xFF;
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if (in[i + 3] != '=')
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out[j + 2] = v & 0xFF;
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}
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return 1;
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}
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