Burrows-Wheeler-transform-based compressors rely on local context regularity, but structured text also contains dates, counters, identifiers, coordinates, and other digit runs whose values vary differently from their surrounding tokens. STC is a practical BWT-family compressor that separates this source of variation before the component BWT stage. It replaces digit runs in the main stream with an unambiguous placeholder and stores the removed digits in length- and context-conditioned side streams. The side streams use stable bucket ordering and compact digit packing, so the decoder can reconstruct the original run order from the normalized main stream without storing a separate permutation. The resulting components are encoded by a fixed internal BWT/M03-style component coder. On enwik9, STC produces a 157,388,188-byte archive with a 183,174-byte decoder source package, giving a local LTCB-style total of 157,571,362 bytes. A full-enwik9 same-coder ablation shows that the digit-context decomposition reduces the archive by 2,629,561 bytes relative to the no-split control. The result is locally verified by full decode and SHA-256 matching; official benchmark status requires independent maintainer-side verification.

翻译：基于Burrows-Wheeler变换的压缩器依赖于局部上下文规律性，但结构化文本中常含日期、计数器、标识符、坐标等数字串，其数值变化方式与周围词元不同。STC作为一种实用的BWT族压缩器，在BWT阶段前分离此类变异源：以无歧义占位符替换主数据流中的数字串，并将移除的数字存储于长度及上下文条件化的侧数据流中。侧数据流采用稳定桶排序与紧致数字打包策略，使得解码器无需存储额外置换即可从归一化的主数据流重建原始数字串顺序。各组件经由固定内部BWT/M03风格组件编码器进行编码。在enwik9上，STC生成157,388,188字节压缩包及183,174字节解码器源码包，对应的本地LTCB风格总长度为157,571,362字节。基于同一编码器的完整enwik9消融实验表明，数字上下文分解相较于无分割控制组减少2,629,561字节压缩量。结果经完整解码与SHA-256匹配在本地方可验证；官方基准状态需由维护方独立验证。