mirror of
https://github.com/fumiama/base16384.git
synced 2026-06-09 04:30:26 +08:00
214 lines
6.7 KiB
C
214 lines
6.7 KiB
C
//basex64.c
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//fumiama 20210407
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#include <stdio.h>
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#include <stdlib.h>
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#include "base1464le.h"
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//#define DEBUG
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LENDAT* encode(const char* data, const u_int64_t len) {
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LENDAT* encd = (LENDAT*)malloc(sizeof(LENDAT));
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uint64_t outlen = len / 7 * 8;
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uint8_t offset = len % 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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#ifdef DEBUG
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printf("outlen: %llu, offset: %u, malloc: %llu\n", outlen, offset, outlen + 8);
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#endif
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encd->data = (uint8_t*)malloc(outlen + 8); //冗余的8B用于可能的结尾的覆盖
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encd->len = outlen;
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uint64_t* vals = (uint64_t*)(encd->data);
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uint64_t n = 0;
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uint64_t i = 0;
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for(; i < len - 7; i += 7) {
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register uint64_t sum = 0x000000000000003f & ((uint64_t)data[i] >> 2);
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sum |= ((((uint64_t)data[i + 1] >> 2) | (data[i] << 6)) << 8) & 0x000000000000ff00;
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sum |= ((((uint64_t)data[i + 1] << 4) | ((uint64_t)data[i + 2] >> 4)) << 16) & 0x00000000003f0000;
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sum |= ((((uint64_t)data[i + 2] << 4) | ((uint64_t)data[i + 3] >> 4)) << 24) & 0x00000000ff000000;
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sum |= ((((uint64_t)data[i + 3] << 2) | ((uint64_t)data[i + 4] >> 6)) << 32) & 0x0000003f00000000;
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sum |= ((((uint64_t)data[i + 4] << 2) | ((uint64_t)data[i + 5] >> 6)) << 40) & 0x0000ff0000000000;
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sum |= ((uint64_t)data[i + 5] << 48) & 0x003f000000000000;
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sum |= ((uint64_t)data[i + 6] << 56) & 0xff00000000000000;
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sum += 0x004e004e004e004e;
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vals[n++] = sum;
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#ifdef DEBUG
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printf("i: %llu, add sum: %016llx\n", i, sum);
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#endif
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}
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if(offset > 0) {
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register uint64_t sum = 0x000000000000003f & (data[i] >> 2);
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sum |= (((uint64_t)data[i] << 6) << 8) & 0x000000000000c000;
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if(offset > 1) {
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sum |= (((uint64_t)data[i + 1] >> 2) << 8) & 0x0000000000003f00;
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sum |= (((uint64_t)data[i + 1] << 4) << 16) & 0x0000000000300000;
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if(offset > 2) {
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sum |= (((uint64_t)data[i + 2] >> 4) << 16) & 0x00000000000f0000;
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sum |= (((uint64_t)data[i + 2] << 4) << 24) & 0x00000000f0000000;
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if(offset > 3) {
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sum |= (((uint64_t)data[i + 3] >> 4) << 24) & 0x000000000f000000;
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sum |= (((uint64_t)data[i + 3] << 2) << 32) & 0x0000003c00000000;
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if(offset > 4) {
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sum |= (((uint64_t)data[i + 4] >> 6) << 32) & 0x0000000300000000;
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sum |= (((uint64_t)data[i + 4] << 2) << 40) & 0x0000fc0000000000;
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if(offset > 5) {
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sum |= (((uint64_t)data[i + 5] >> 6) << 40) & 0x0000030000000000;
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sum |= ((uint64_t)data[i + 5] << 48) & 0x003f000000000000;
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}
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}
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}
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}
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}
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sum += 0x004e004e004e004e;
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vals[n] = sum;
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#ifdef DEBUG
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printf("i: %llu, add sum: %016llx\n", i, sum);
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#endif
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encd->data[outlen - 2] = '=';
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encd->data[outlen - 1] = offset;
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}
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return encd;
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}
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LENDAT* decode(const char* data, const u_int64_t len) {
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LENDAT* decd = (LENDAT*)malloc(sizeof(LENDAT));
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uint64_t outlen = len;
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uint8_t offset = 0;
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if(data[len-2] == '=') {
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offset = data[len-1];
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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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}
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outlen = outlen / 8 * 7 + offset;
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decd->data = (uint8_t*)malloc(outlen);
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decd->len = outlen;
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uint64_t* vals = (uint64_t*)data;
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uint64_t n = 0;
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uint64_t i = 0;
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for(; n < len / 8; n++) {
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register uint64_t sum = vals[n];
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sum -= 0x004e004e004e004e;
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decd->data[i++] = ((sum & 0x000000000000003f) << 2) | ((sum & 0x000000000000c000) >> 14);
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decd->data[i++] = ((sum & 0x0000000000003f00) >> 6) | ((sum & 0x0000000000300000) >> 20);
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decd->data[i++] = ((sum & 0x00000000000f0000) >> 12) | ((sum & 0x00000000f0000000) >> 28);
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decd->data[i++] = ((sum & 0x000000000f000000) >> 20) | ((sum & 0x0000003c00000000) >> 34);
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decd->data[i++] = ((sum & 0x0000000300000000) >> 26) | ((sum & 0x0000fc0000000000) >> 42);
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decd->data[i++] = ((sum & 0x0000030000000000) >> 34) | ((sum & 0x003f000000000000) >> 48);
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decd->data[i++] = ((sum & 0xff00000000000000) >> 56);
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}
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if(offset > 0) {
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register uint64_t sum = vals[n];
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sum -= 0x000000000000004e;
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decd->data[i++] = ((sum & 0x000000000000003f) << 2) | ((sum & 0x000000000000c000) >> 14);
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if(offset > 1) {
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sum -= 0x00000000004e0000;
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decd->data[i++] = ((sum & 0x0000000000003f00) >> 6) | ((sum & 0x0000000000300000) >> 20);
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if(offset > 2) {
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decd->data[i++] = ((sum & 0x00000000000f0000) >> 12) | ((sum & 0x00000000f0000000) >> 28);
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if(offset > 3) {
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sum -= 0x0000004e00000000;
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decd->data[i++] = ((sum & 0x000000000f000000) >> 20) | ((sum & 0x0000003c00000000) >> 34);
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if(offset > 4) {
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decd->data[i++] = ((sum & 0x0000000300000000) >> 26) | ((sum & 0x0000fc0000000000) >> 42);
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if(offset > 5) {
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sum -= 0x004e000000000000;
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decd->data[i++] = ((sum & 0x0000030000000000) >> 34) | ((sum & 0x003f000000000000) >> 48);
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}
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}
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}
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}
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}
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}
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return decd;
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}
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void encode_file(const char* input, const char* output) {
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FILE* fp = NULL;
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fp = fopen(input, "rb");
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if(fp) {
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FILE* fpo = NULL;
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fpo = fopen(output, "wb");
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if(fpo) {
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char* bufi = (char*)malloc(B14BUFSIZ/7*7);
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if(bufi) {
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int cnt = 0;
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fputc(0xFE, fpo);
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fputc(0xFF, fpo);
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while((cnt = fread(bufi, 1, B14BUFSIZ/7*7, fp))) {
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LENDAT* ld = encode(bufi, cnt);
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if(fwrite(ld->data, ld->len, 1, fpo) <= 0) {
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puts("Write file error!");
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exit(EXIT_FAILURE);
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}
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free(ld);
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}
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free(bufi);
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} else puts("Allocate input buffer error!");
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fclose(fpo);
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} else puts("Open output file error!");
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fclose(fp);
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} else puts("Open input file error!");
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}
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int rm_head(FILE* fp) {
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int ch = fgetc(fp);
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if(ch == 0xFE) fgetc(fp);
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else rewind(fp);
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}
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void decode_file(const char* input, const char* output) {
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FILE* fp = NULL;
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fp = fopen(input, "rb");
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if(fp) {
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FILE* fpo = NULL;
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fpo = fopen(output, "wb");
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if(fpo) {
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char* bufi = (char*)malloc(B14BUFSIZ/8*8);
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if(bufi) {
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int cnt = 0;
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rm_head(fp);
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while((cnt = fread(bufi, 1, B14BUFSIZ/7*7, fp))) {
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LENDAT* ld = decode(bufi, cnt);
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if(fwrite(ld->data, ld->len, 1, fpo) <= 0) {
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puts("Write file error!");
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exit(EXIT_FAILURE);
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}
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free(ld);
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}
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free(bufi);
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} else puts("Allocate input buffer error!");
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fclose(fpo);
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} else puts("Open output file error!");
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fclose(fp);
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} else puts("Open input file error!");
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}
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#define B1464LE_TEST
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#ifdef B1464LE_TEST
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int main(int argc, char** argv) {
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LENDAT* ld = encode("just a simple test from fumiama", 32);
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//puts(ld->data);
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LENDAT* le = decode(ld->data, ld->len);
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puts(le->data);
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if(argc == 4) {
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encode_file(argv[1], argv[2]);
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decode_file(argv[2], argv[3]);
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}
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}
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#endif
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