新的设计

64/base1464le.c

@@ -0,0 +1,140 @@
+//basex64.c
+//fumiama 20210407
+#include <stdio.h>
+#include <stdlib.h>
+#include "base1464le.h"
+
+#define DEBUG
+
+LENDAT* encode(const char* data, const u_int64_t len) {
+	LENDAT* encd = (LENDAT*)malloc(sizeof(LENDAT));
+	uint64_t outlen = len / 7 * 8;
+	uint8_t offset = len % 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
+	encd->data = (uint8_t*)malloc(outlen + 8);	//冗余的8B用于可能的结尾的覆盖
+	encd->len = outlen;
+	uint64_t* vals = (uint64_t*)(encd->data);
+	uint64_t n = 0;
+	uint64_t i = 0;
+	for(; i < len - 7; i *= 7) {
+		register uint64_t sum = 0x000000000000003f & ((uint64_t)data[i] >> 2);
+		sum |= ((((uint64_t)data[i + 1] >> 2) | (data[i] << 6)) << 8) & 0x000000000000ff00;
+		sum |= ((((uint64_t)data[i + 1] << 4) | ((uint64_t)data[i + 2] >> 4)) << 16) & 0x00000000003f0000;
+		sum |= ((((uint64_t)data[i + 2] << 4) | ((uint64_t)data[i + 3] >> 4)) << 24) & 0x00000000ff000000;
+		sum |= ((((uint64_t)data[i + 3] << 2) | ((uint64_t)data[i + 4] >> 6)) << 32) & 0x0000003f00000000;
+		sum |= ((((uint64_t)data[i + 4] << 2) | ((uint64_t)data[i + 5] >> 6)) << 40) & 0x0000ff0000000000;
+		sum |= (((uint64_t)data[i + 5] << 2) << 48) & 0x003f000000000000;
+		sum |= ((uint64_t)data[i + 6] << 56) & 0xff00000000000000;
+		sum += 0x004e004e004e004e;
+		vals[n++] = sum;
+	}
+	i /= 7;
+	if(offset > 0) {
+		register uint64_t sum = 0x000000000000003f & (data[i] >> 2);
+		sum |= (((uint64_t)data[i] << 6) << 8) & 0x000000000000c000;
+		if(offset > 1) {
+			sum |= (((uint64_t)data[i + 1] >> 2) << 8) & 0x0000000000003f00;
+			sum |= (((uint64_t)data[i + 1] << 4) << 16) & 0x0000000000300000;
+			if(offset > 2) {
+				sum |= (((uint64_t)data[i + 2] >> 4) << 16) & 0x00000000000f0000;
+				sum |= (((uint64_t)data[i + 2] << 4) << 24) & 0x00000000f0000000;
+				if(offset > 3) {
+					sum |= (((uint64_t)data[i + 3] >> 4) << 24) & 0x000000000f000000;
+					sum |= (((uint64_t)data[i + 3] << 2) << 32) & 0x0000003c00000000;
+					if(offset > 4) {
+						sum |= (((uint64_t)data[i + 4] >> 6) << 32) & 0x0000000300000000;
+						sum |= (((uint64_t)data[i + 4] << 2) << 40) & 0x0000fc0000000000;
+						if(offset > 5) {
+							sum |= (((uint64_t)data[i + 5] >> 6) << 40) & 0x0000030000000000;
+							sum |= (((uint64_t)data[i + 5] << 2) << 48) & 0x003f000000000000;
+						}
+					}
+				}
+			}
+		}
+		sum += 0x004e004e004e004e;
+		vals[n] = sum;
+		encd->data[outlen - 2] = '=';
+		encd->data[outlen - 1] = offset;
+	}
+	return encd;
+}
+
+LENDAT* decode(const char* data, const u_int64_t len) {
+	LENDAT* decd = (LENDAT*)malloc(sizeof(LENDAT));
+	uint64_t outlen = len;
+	uint8_t offset = 0;
+	if(data[len-2] == '=') {
+		offset = data[len-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;
+	decd->data = (uint8_t*)malloc(outlen);
+	decd->len = outlen;
+	uint64_t* vals = (uint64_t*)data;
+	uint64_t n = 0;
+	uint64_t i = 0;
+	for(; n < len / 8; n++) {
+		register uint64_t sum = vals[n];
+		sum -= 0x004e004e004e004e;
+		decd->data[i++] = ((sum & 0x000000000000003f) << 2) | ((sum & 0x000000000000c000) >> 14);
+		decd->data[i++] = ((sum & 0x0000000000003f00) >> 6) | ((sum & 0x0000000000300000) >> 20);
+		decd->data[i++] = ((sum & 0x00000000000f0000) >> 12) | ((sum & 0x00000000f0000000) >> 28);
+		decd->data[i++] = ((sum & 0x000000000f000000) >> 20) | ((sum & 0x0000003c00000000) >> 34);
+		decd->data[i++] = ((sum & 0x0000000300000000) >> 26) | ((sum & 0x0000fc0000000000) >> 42);
+		decd->data[i++] = ((sum & 0x0000030000000000) >> 34) | ((sum & 0x003f000000000000) >> 48);
+		decd->data[i++] = ((sum & 0xff00000000000000) >> 56);
+	}
+	if(offset > 0) {
+		register uint64_t sum = vals[n];
+		sum -= 0x000000000000004e;
+		decd->data[i++] = ((sum & 0x000000000000003f) << 2) | ((sum & 0x000000000000c000) >> 14);
+		if(offset > 1) {
+			sum -= 0x00000000004e0000;
+			decd->data[i++] = ((sum & 0x0000000000003f00) >> 6) | ((sum & 0x0000000000300000) >> 20);
+			if(offset > 2) {
+				decd->data[i++] = ((sum & 0x00000000000f0000) >> 12) | ((sum & 0x00000000f0000000) >> 28);
+				if(offset > 3) {
+					sum -= 0x0000004e00000000;
+					decd->data[i++] = ((sum & 0x000000000f000000) >> 20) | ((sum & 0x0000003c00000000) >> 34);
+					if(offset > 4) {
+						decd->data[i++] = ((sum & 0x0000000300000000) >> 26) | ((sum & 0x0000fc0000000000) >> 42);
+						if(offset > 5) {
+							sum -= 0x004e000000000000;
+							decd->data[i++] = ((sum & 0x0000030000000000) >> 34) | ((sum & 0x003f000000000000) >> 48);
+						}
+					}
+				}
+			}
+		}
+	}
+	return decd;
+}
+
+int main() {
+	LENDAT* ld = encode("simple test addafiaofhiowq cfaiohfoiqwnfioqw", 45);
+	puts(ld->data);
+	LENDAT* le = decode(ld->data, ld->len);
+	puts(le->data);
+}

64/base1464le.h

@@ -0,0 +1,7 @@
+#include <stdint.h>
+
+struct LENDAT {
+    uint8_t* data;
+    uint64_t len;
+};
+typedef struct LENDAT LENDAT;