8bit/16bit RLE_易语言 rle-优快云博客

本文详细介绍了两种文件压缩格式：8位头部版本和16位头部版本。每种格式都包含了原始文件名及后续的压缩数据结构。8位版本使用单字节头，而16位版本则采用双字节头来指示重复字符或数据序列的长度，支持更长的数据段。

========= tech info =========

8 bit header version.

File format:

13 byte original filename, followed by

[ 8 bit header + data ][ 8 bit header + data ][ 8 bit header + data ]
etc..

header:

bit 7         : 1 if following byte is a run
bit 6 - 0     : legnth of run (max 127, min 3)

data: 1 byte : which character run consists of

*** OR ***

header:

bit 7         : 0 if following bytes are sequence
bit 6 - 0     : legnth of sequence (max 127)

data: (header AND 0x7F) bytes of data
                : data bytes copied to output stream unchanged

===============================

========= tech info =========

16 bit header version.

File format:

13 bytes : original filename, followed by:

[ 16 bit header + data ][ 16 bit header + data ][16 bit header + data ]
etc..

header:
[lo byte][hi byte] ==> turn into 16 bit int ==>

bit 15        : 1 if following byte is a run
bit 14 - 0    : length of run (max 32767, min 4)

data: 1 byte : which character run consists of

*** OR ***

header:
[lo byte][hi byte] ==> turn into 16 bit int ==>

bit 15        : 0 if following bytes are sequence
bit 14 - 0    : length of sequence (max 32767)

data: (header & 0x7FFF) bytes of data
                : data bytes copied to output stream unchanged

===============================