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feat(coder): add safe encode/decode

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源文雨
2024-04-04 23:58:05 +09:00
parent b451127638
commit 2622a5ad69
8 changed files with 435 additions and 29 deletions
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179
base1464.c
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@@ -16,8 +16,107 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include "binary.h"
union remainder {
uint8_t buf[8];
uint64_t val;
};
typedef union remainder remainder;
int base16384_encode_safe(const char* data, int dlen, char* buf) {
int outlen = dlen / 7 * 8;
int offset = dlen % 7;
switch(offset) { // 算上偏移标志字符占用的2字节
case 0: break;
case 1: outlen += 4; break;
case 2:
case 3: outlen += 6; break;
case 4:
case 5: outlen += 8; break;
case 6: outlen += 10; break;
default: break;
}
#ifdef DEBUG
printf("outlen: %llu, offset: %u, malloc: %llu\n", outlen, offset, outlen + 8);
#endif
uint64_t* vals = (uint64_t*)buf;
uint64_t n = 0;
int64_t i = 0;
for(; i < dlen - 7; i += 7) {
register uint64_t sum = 0;
register uint64_t shift = htobe64(*(uint64_t*)(data+i))>>2;
sum |= shift & 0x3fff000000000000;
shift >>= 2;
sum |= shift & 0x00003fff00000000;
shift >>= 2;
sum |= shift & 0x000000003fff0000;
shift >>= 2;
sum |= shift & 0x0000000000003fff;
sum += 0x4e004e004e004e00;
vals[n++] = be64toh(sum);
#ifdef DEBUG
printf("i: %llu, add sum: %016llx\n", i, sum);
#endif
}
remainder valbuf;
if(dlen - i == 7) {
memcpy(valbuf.buf, data+i, 7);
register uint64_t sum = 0;
register uint64_t shift = htobe64(valbuf.val)>>2;
sum |= shift & 0x3fff000000000000;
shift >>= 2;
sum |= shift & 0x00003fff00000000;
shift >>= 2;
sum |= shift & 0x000000003fff0000;
shift >>= 2;
sum |= shift & 0x0000000000003fff;
sum += 0x4e004e004e004e00;
vals[n++] = be64toh(sum);
return outlen;
}
int o = offset;
if(o--) {
register uint64_t sum = 0x000000000000003f & (data[i] >> 2);
sum |= ((uint64_t)data[i] << 14) & 0x000000000000c000;
if(o--) {
sum |= ((uint64_t)data[i + 1] << 6) & 0x0000000000003f00;
sum |= ((uint64_t)data[i + 1] << 20) & 0x0000000000300000;
if(o--) {
sum |= ((uint64_t)data[i + 2] << 12) & 0x00000000000f0000;
sum |= ((uint64_t)data[i + 2] << 28) & 0x00000000f0000000;
if(o--) {
sum |= ((uint64_t)data[i + 3] << 20) & 0x000000000f000000;
sum |= ((uint64_t)data[i + 3] << 34) & 0x0000003c00000000;
if(o--) {
sum |= ((uint64_t)data[i + 4] << 26) & 0x0000000300000000;
sum |= ((uint64_t)data[i + 4] << 42) & 0x0000fc0000000000;
if(o--) {
sum |= ((uint64_t)data[i + 5] << 34) & 0x0000030000000000;
sum |= ((uint64_t)data[i + 5] << 48) & 0x003f000000000000;
}
}
}
}
}
sum += 0x004e004e004e004e;
#ifdef WORDS_BIGENDIAN
valbuf.val = __builtin_bswap64(sum);
#else
valbuf.val = sum;
#endif
memcpy(&vals[n], valbuf.buf, outlen-2-(int)n*(int)sizeof(uint64_t));
#ifdef DEBUG
printf("i: %llu, add sum: %016llx\n", i, sum);
#endif
buf[outlen - 2] = '=';
buf[outlen - 1] = offset;
}
return outlen;
}
int base16384_encode(const char* data, int dlen, char* buf) {
int outlen = dlen / 7 * 8;
int offset = dlen % 7;
@@ -134,6 +233,86 @@ int base16384_encode_unsafe(const char* data, int dlen, char* buf) {
return outlen;
}
int base16384_decode_safe(const char* data, int dlen, char* buf) {
int outlen = dlen;
int offset = 0;
if(data[dlen-2] == '=') {
offset = data[dlen-1];
switch(offset) { // 算上偏移标志字符占用的2字节
case 0: break;
case 1: outlen -= 4; break;
case 2:
case 3: outlen -= 6; break;
case 4:
case 5: outlen -= 8; break;
case 6: outlen -= 10; break;
default: break;
}
}
outlen = outlen / 8 * 7 + offset;
uint64_t* vals = (uint64_t*)data;
uint64_t n = 0;
int64_t i = 0;
for(; i < outlen - 7; n++, i+=7) {
register uint64_t sum = 0;
register uint64_t shift = htobe64(vals[n]) - 0x4e004e004e004e00;
shift <<= 2;
sum |= shift & 0xfffc000000000000;
shift <<= 2;
sum |= shift & 0x0003fff000000000;
shift <<= 2;
sum |= shift & 0x0000000fffc00000;
shift <<= 2;
sum |= shift & 0x00000000003fff00;
*(uint64_t*)(buf+i) = be64toh(sum);
#ifdef DEBUG
printf("i: %llu, add sum: %016llx\n", i, sum);
#endif
}
remainder valbuf;
if(outlen - i == 7) {
register uint64_t sum = 0;
register uint64_t shift = htobe64(vals[n]) - 0x4e004e004e004e00;
shift <<= 2;
sum |= shift & 0xfffc000000000000;
shift <<= 2;
sum |= shift & 0x0003fff000000000;
shift <<= 2;
sum |= shift & 0x0000000fffc00000;
shift <<= 2;
sum |= shift & 0x00000000003fff00;
valbuf.val = be64toh(sum);
memcpy(buf+i, valbuf.buf, 7);
} else if(offset--) {
memcpy(valbuf.buf, &vals[n], dlen-2-(int)n*(int)sizeof(uint64_t));
#ifdef WORDS_BIGENDIAN
register uint64_t sum = __builtin_bswap64(valbuf.val) - 0x000000000000004e;
#else
register uint64_t sum = valbuf.val - 0x000000000000004e;
#endif
buf[i++] = ((sum & 0x000000000000003f) << 2) | ((sum & 0x000000000000c000) >> 14);
if(offset--) {
sum -= 0x00000000004e0000;
buf[i++] = ((sum & 0x0000000000003f00) >> 6) | ((sum & 0x0000000000300000) >> 20);
if(offset--) {
buf[i++] = ((sum & 0x00000000000f0000) >> 12) | ((sum & 0x00000000f0000000) >> 28);
if(offset--) {
sum -= 0x0000004e00000000;
buf[i++] = ((sum & 0x000000000f000000) >> 20) | ((sum & 0x0000003c00000000) >> 34);
if(offset--) {
buf[i++] = ((sum & 0x0000000300000000) >> 26) | ((sum & 0x0000fc0000000000) >> 42);
if(offset--) {
sum -= 0x004e000000000000;
buf[i] = ((sum & 0x0000030000000000) >> 34) | ((sum & 0x003f000000000000) >> 48);
}
}
}
}
}
}
return outlen;
}
int base16384_decode(const char* data, int dlen, char* buf) {
int outlen = dlen;
int offset = 0;