Module cost 

Byte-length predictors for emitted ANSI sequences.

Category

Cost functions mirror writer functions in crate::ansi::cursor and crate::ansi::screen. They let render planning compare equivalent cursor, erase, scroll, and overwrite strategies without allocating formatted strings.

Conventions

Costs are byte counts for the exact 7-bit sequences emitted by this crate, including omitted default parameters such as ESC [ A for CUU 1 and ESC [ H for home.

Mode interaction

The predictors do not change terminal modes. For mode-sensitive sequences, such as left/right margins requiring Mode::LEFT_RIGHT_MARGIN, the cost still describes only the bytes emitted.

Constants

CR_COST

Cost of a carriage return (\r).

DECSTBM_RESET_COST

Cost of resetting DECSTBM to the full screen (\x1b[r).

HOME_COST

Cost of an absolute home jump (\x1b[H).

RI_COST

Cost of Reverse Index (\x1bM).

Functions

bs_cost

Cost of n literal backspace bytes.

cbt_cost

Cost of CBT (\x1b[{n?}Z).

cha_cost

Cost of CHA (\x1b[{col+1?}G). The writer drops the parameter when col == 0.

cht_cost

Cost of CHT (\x1b[{n?}I).

cub_cost

Cost of CUB (\x1b[{n?}D).

cud_cost

Cost of CUD (\x1b[{n?}B).

cuf_cost

Cost of CUF (\x1b[{n?}C).

cup_cost

Cost of a CUP sequence for the given 0-based position. The writer drops the column when it is 0, and drops both parameters when the destination is the origin.

cuu_cost

Cost of CUU (\x1b[{n?}A).

dch_cost

Cost of DCH (\x1b[{n?}P).

decstbm_cost

Cost of DECSTBM (\x1b[{top+1};{bottom+1}r).

digit_count

Number of decimal digits in a u16. Branchy table — faster than ilog10 on the small range we feed it (cursor coordinates, repeat counts).

dl_cost

Cost of DL (\x1b[{n?}M).

ech_cost

Cost of ECH (\x1b[{n?}X).

ed_cost

Cost of ED (\x1b[{n?}J). n == 0 omits the parameter.

el_cost

Cost of EL (\x1b[{n?}K). n == 0 omits the parameter.

hpa_cost

Cost of HPA (\x1b[{col+1?}` ). The writer drops the parameter when col == 0.

ich_cost

Cost of ICH (\x1b[{n?}@).

il_cost

Cost of IL (\x1b[{n?}L).

lf_cost

Cost of n literal line-feed bytes.

overwrite_cost

Approximate byte cost of re-emitting the cells in line[from..to] as a forward-move candidate.

rep_cost

Cost of REP (\x1b[{n?}b).

sd_cost

Cost of SD (\x1b[{n?}T).

su_cost

Cost of SU (\x1b[{n?}S).

tab_cost

Cost of n literal tab bytes.

vpa_cost

Cost of VPA (\x1b[{row+1?}d). The writer drops the parameter when row == 0.