/* * Base64 encoding/decoding (RFC1341) * Copyright (c) 2005, Jouni Malinen <j@w1.fi> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Alternatively, this software may be distributed under the terms of BSD * license. * */ #include "base64.h" #include <string.h> static const uint8_t dtable[] = {0x3e, 0x80, 0x80, 0x80, 0x3f, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x80, 0x80, 0x80, 0x0, 0x80, 0x80, 0x80, 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33}; // "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; static uint8_t get_dtable_value(uint8_t index) { return (index < 43 || index > 122) ? 0x80 : dtable[index - 43]; } uint8_t* base64_decode(const uint8_t* src, size_t len, size_t* out_len, size_t* out_size) { uint8_t *out; uint8_t *pos; uint8_t in[4]; uint8_t block[4]; uint8_t tmp; size_t i; size_t count; size_t olen; count = 0; for(i = 0; i < len; i++) { if(get_dtable_value(src[i]) != 0x80) count++; } if(count == 0 || count % 4) return NULL; olen = count / 4 * 3; pos = out = malloc(olen); *out_size = olen; if(out == NULL) return NULL; count = 0; for(i = 0; i < len; i++) { tmp = get_dtable_value(src[i]); if(tmp == 0x80) continue; in[count] = src[i]; block[count] = tmp; count++; if(count == 4) { *pos++ = (block[0] << 2) | (block[1] >> 4); *pos++ = (block[1] << 4) | (block[2] >> 2); *pos++ = (block[2] << 6) | block[3]; count = 0; } } if(pos > out) { if(in[2] == '=') pos -= 2; else if(in[3] == '=') pos--; } *out_len = pos - out; return out; }