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89 lines
3.0 KiB
C
89 lines
3.0 KiB
C
#ifndef _BASE16384_H_
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#define _BASE16384_H_
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/* base16384.h
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* This file is part of the base16384 distribution (https://github.com/fumiama/base16384).
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* Copyright (c) 2022 Fumiama Minamoto.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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// base16384_err_t is the return value of base16384_en/decode_file
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enum base16384_err_t {
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base16384_err_ok,
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base16384_err_get_file_size,
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base16384_err_fopen_output_file,
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base16384_err_fopen_input_file,
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base16384_err_write_file,
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base16384_err_open_input_file,
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base16384_err_map_input_file,
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};
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// base16384_err_t is the return value of base16384_en/decode_file
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typedef enum base16384_err_t base16384_err_t;
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#define BASE16384_ENCBUFSZ (BUFSIZ*1024/7*7)
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#define BASE16384_DECBUFSZ (BUFSIZ*1024/8*8+2)
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// base16384_encode_len calc min buf size to fill encode result
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static inline int base16384_encode_len(int dlen) {
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int outlen = dlen / 7 * 8;
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int offset = dlen % 7;
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switch(offset) { // 算上偏移标志字符占用的2字节
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case 0: break;
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case 1: outlen += 4; break;
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case 2:
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case 3: outlen += 6; break;
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case 4:
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case 5: outlen += 8; break;
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case 6: outlen += 10; break;
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default: break;
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}
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return outlen + 8; // 冗余的8B用于可能的结尾的覆盖
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}
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// base16384_decode_len calc min buf size to fill decode result
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static inline int base16384_decode_len(int dlen, int offset) {
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int outlen = dlen;
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switch(offset) { // 算上偏移标志字符占用的2字节
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case 0: break;
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case 1: outlen -= 4; break;
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case 2:
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case 3: outlen -= 6; break;
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case 4:
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case 5: outlen -= 8; break;
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case 6: outlen -= 10; break;
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default: break;
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}
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return outlen / 8 * 7 + offset + 1; // 多出1字节用于循环覆盖
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}
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// base16384_encode encodes data and write result into buf
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int base16384_encode(const char* data, int dlen, char* buf, int blen);
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// base16384_decode decodes data and write result into buf
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int base16384_decode(const char* data, int dlen, char* buf, int blen);
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// base16384_encode_file encodes input file to output file.
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// use `-` to specify stdin/stdout
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// encbuf & decbuf must be no less than BASE16384_ENCBUFSZ & BASE16384_DECBUFSZ
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base16384_err_t base16384_encode_file(const char* input, const char* output, char* encbuf, char* decbuf);
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// base16384_decode_file decodes input file to output file.
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// use `-` to specify stdin/stdout
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// encbuf & decbuf must be no less than BASE16384_ENCBUFSZ & BASE16384_DECBUFSZ
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base16384_err_t base16384_decode_file(const char* input, const char* output, char* encbuf, char* decbuf);
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#endif
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