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https://github.com/fumiama/android-base16384.git
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v3.0
1. 使用新算法，大幅提升编解码速度。 2. 新算法不向后兼容，但在大部分情况下可保证接近的结果。 3. 如果想使用旧算法，请前往github仓库页面的traditional_ver文件夹中自行编译使用
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fumiama
151
app/src/main/cpp/base14/32/base1432le.c
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151
app/src/main/cpp/base14/32/base1432le.c
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//base1432le.c
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//fumiama 20210408
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#include <stdio.h>
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#include <stdlib.h>
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#include "base1432le.h"
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//#define DEBUG
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LENDAT* encode(const uint8_t* data, const u_int32_t len) {
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LENDAT* encd = (LENDAT*)malloc(sizeof(LENDAT));
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uint32_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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uint32_t* vals = (uint32_t*)(encd->data);
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uint32_t n = 0;
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uint32_t i = 0;
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for(; i < len; i += 7) {
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register uint32_t sum = 0x0000003f & ((uint32_t)data[i] >> 2);
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sum |= ((((uint32_t)data[i + 1] >> 2) | (data[i] << 6)) << 8) & 0x0000ff00;
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sum |= ((((uint32_t)data[i + 1] << 4) | ((uint32_t)data[i + 2] >> 4)) << 16) & 0x003f0000;
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sum |= ((((uint32_t)data[i + 2] << 4) | ((uint32_t)data[i + 3] >> 4)) << 24) & 0xff000000;
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sum += 0x004e004e;
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vals[n++] = sum;
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#ifdef DEBUG
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printf("n: %u, add sum: %08x\n", n, sum);
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#endif
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sum = ((((uint32_t)data[i + 3] << 2) | ((uint32_t)data[i + 4] >> 6))) & 0x0000003f;
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sum |= ((((uint32_t)data[i + 4] << 2) | ((uint32_t)data[i + 5] >> 6)) << 8) & 0x0000ff00;
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sum |= ((uint32_t)data[i + 5] << 16) & 0x003f0000;
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sum |= ((uint32_t)data[i + 6] << 24) & 0xff000000;
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sum += 0x004e004e;
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vals[n++] = sum;
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#ifdef DEBUG
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printf("n: %u, add sum: %08x\n", n, sum);
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#endif
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}
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if(offset > 0) {
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register uint32_t sum = 0x0000003f & (data[i] >> 2);
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sum |= (((uint32_t)data[i] << 6) << 8) & 0x0000c000;
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if(offset > 1) {
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sum |= (((uint32_t)data[i + 1] >> 2) << 8) & 0x00003f00;
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sum |= (((uint32_t)data[i + 1] << 4) << 16) & 0x00300000;
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if(offset > 2) {
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sum |= (((uint32_t)data[i + 2] >> 4) << 16) & 0x000f0000;
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sum |= (((uint32_t)data[i + 2] << 4) << 24) & 0xf0000000;
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if(offset == 2) {
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sum += 0x004e004e;
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vals[n++] = sum;
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}
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if(offset > 3) {
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sum |= (((uint32_t)data[i + 3] >> 4) << 24) & 0x0f000000;
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sum += 0x004e004e;
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vals[n++] = sum;
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sum = (((uint32_t)data[i + 3] << 2)) & 0x0000003c;
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if(offset > 4) {
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sum |= (((uint32_t)data[i + 4] >> 6)) & 0x00000003;
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sum |= (((uint32_t)data[i + 4] << 2) << 8) & 0x0000fc00;
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if(offset > 5) {
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sum |= (((uint32_t)data[i + 5] >> 6) << 8) & 0x00000300;
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sum |= ((uint32_t)data[i + 5] << 16) & 0x003f0000;
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}
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}
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sum += 0x004e004e;
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vals[n] = sum;
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}
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}
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}
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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 uint8_t* data, const u_int32_t len) {
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LENDAT* decd = (LENDAT*)malloc(sizeof(LENDAT));
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uint32_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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uint32_t* vals = (uint32_t*)data;
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uint32_t n = 0;
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uint32_t i = 0;
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for(; n < len / 4; n++) { //n实际每次自增2
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register uint32_t sum = vals[n++];
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sum -= 0x004e004e;
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decd->data[i++] = ((sum & 0x0000003f) << 2) | ((sum & 0x0000c000) >> 14);
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decd->data[i++] = ((sum & 0x00003f00) >> 6) | ((sum & 0x00300000) >> 20);
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decd->data[i++] = ((sum & 0x000f0000) >> 12) | ((sum & 0xf0000000) >> 28);
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decd->data[i] = ((sum & 0x0f000000) >> 20);
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sum = vals[n];
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sum -= 0x004e004e;
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decd->data[i++] |= ((sum & 0x0000003c) >> 2);
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decd->data[i++] = ((sum & 0x00000003) << 6) | ((sum & 0x0000fc00) >> 10);
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decd->data[i++] = ((sum & 0x00000300) >> 2) | ((sum & 0x003f0000) >> 16);
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decd->data[i++] = ((sum & 0xff000000) >> 24);
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}
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if(offset > 0) {
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register uint32_t sum = vals[n++];
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sum -= 0x0000004e;
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decd->data[i++] = ((sum & 0x0000003f) << 2) | ((sum & 0x0000c000) >> 14);
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if(offset > 1) {
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sum -= 0x004e0000;
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decd->data[i++] = ((sum & 0x00003f00) >> 6) | ((sum & 0x00300000) >> 20);
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if(offset > 2) {
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decd->data[i++] = ((sum & 0x000f0000) >> 12) | ((sum & 0xf0000000) >> 28);
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if(offset > 3) {
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decd->data[i++] = (sum & 0x0f000000) >> 20;
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sum = vals[n];
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sum -= 0x0000004e;
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decd->data[i++] |= (sum & 0x0000003c) >> 2;
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if(offset > 4) {
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decd->data[i++] = ((sum & 0x00000003) << 6) | ((sum & 0x0000fc00) >> 10);
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if(offset > 5) {
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sum -= 0x004e0000;
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decd->data[i++] = ((sum & 0x00000300) >> 2) | ((sum & 0x003f0000) >> 16);
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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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