COBS（Consistent Overhead Byte Stuffing，恒定开销的字节填充）是一种固定开销的字节填充算法。字节填充用于处理那些包含了特殊或保留字符的字符序列编码，通过一定的算法在原有的字符序列长度+1 生成编码后的字符序列，新的序列将不会包含之前序列中出现的特殊或者保留的字符。

在ForN版本中,编码后的有效字节均为非0数据 （1~255）。以为数据0为结束。编码中0xFF为超出255而做中继. 该种编码的特点是整个数据帧有且只有一个数据0,而且它为结束数据, 这样对于分包处理有明显的分割.

参考::>

https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing

讯享网

=====C语言版本=========

#include <stdint.h> #include <assert.h> / COBS encode data to buffer @param data Pointer to input data to encode @param length Number of bytes to encode @param buffer Pointer to encoded output buffer @return Encoded buffer length in bytes @note Does not output delimiter byte */ size_t cobsEncode(const void *data, size_t length, uint8_t *buffer) { assert(data && buffer); uint8_t *encode = buffer; // Encoded byte pointer uint8_t *codep = encode++; // Output code pointer uint8_t code = 1; // Code value for (const uint8_t *byte = (const uint8_t *)data; length--; ++byte) { if (*byte) // Byte not zero, write it *encode++ = *byte, ++code; if (!*byte || code == 0xff) // Input is zero or block completed, restart { *codep = code, code = 1, codep = encode; if (!*byte || length) ++encode; } } *codep = code; // Write final code value return encode - buffer; } / COBS decode data from buffer @param buffer Pointer to encoded input bytes @param length Number of bytes to decode @param data Pointer to decoded output data @return Number of bytes successfully decoded @note Stops decoding if delimiter byte is found */ size_t cobsDecode(const uint8_t *buffer, size_t length, void *data) { assert(buffer && data); const uint8_t *byte = buffer; // Encoded input byte pointer uint8_t *decode = (uint8_t *)data; // Decoded output byte pointer for (uint8_t code = 0xff, block = 0; byte < buffer + length; --block) { if (block) // Decode block byte *decode++ = *byte++; else { if (code != 0xff) // Encoded zero, write it *decode++ = 0; block = code = *byte++; // Next block length if (code == 0x00) // Delimiter code found break; } } return decode - (uint8_t *)data; }

==============Java版本====================

讯享网 public static int[] COBS_Encoded(int[] data_in) { ArrayList encodeList = new ArrayList(); encodeList.add(0); int i,len = data_in.length; int zeroPos = 0; int zeroAdds= 1; int temp = 0; for(i=0;i<len;i++) { encodeList.add( data_in[i] ); } encodeList.add(0); for(i=1;i<encodeList.size();i++) { temp = (int)encodeList.get(i); if( temp == 0 ) { encodeList.set(zeroPos,zeroAdds); zeroPos += zeroAdds; zeroAdds = 0; } zeroAdds++; if( zeroAdds>=0xFF) { encodeList.set(zeroPos,0xFF); encodeList.add(i+1,0); i++; zeroPos += zeroAdds; zeroAdds = 1; } } len = encodeList.size(); int[] retDst = new int[len]; for(i=0;i<len;i++) { retDst[i] = (int)encodeList.get(i); } return retDst; } public static int[] COBS_Decode(int[] data) { int i,len = data.length; int temp = 0; ArrayList encodeList = new ArrayList(); for(i=0;i<len;i++) { encodeList.add(i,data[i]); } int zValue = data[0]; int zIndex = 0; for(i=0;i<encodeList.size();i++) { temp = (int)encodeList.get(i); if(zIndex==zValue) { if(zValue == 0xFF ) { temp = (int)encodeList.get(i);//key position encodeList.remove(i); }else{ encodeList.set(i,0); } zIndex = 0; zValue = temp; } zIndex++; } encodeList.remove(0); len = encodeList.size(); if( (int)encodeList.get(len-1) == 0x00) { encodeList.remove(len-1); len--; } int[] retDst = new int[len]; for(i=0;i<len;i++) { retDst[i] = (int)encodeList.get(i); } return retDst; }