Module compact_cache 

Compact layout property cache — three-tier numeric encoding

Replaces BTreeMap-based CSS property lookups with cache-friendly arrays. See scripts/COMPACT_CACHE_PLAN.md for design rationale.

• Tier 1: Vec<u64> — ALL 21 enum properties bitpacked (8 B/node)
• Tier 2: Vec<CompactNodeProps> — numeric dimensions + border colors/styles (96 B/node)
• Tier 2b: Vec<CompactTextProps> — text/IFC properties (24 B/node)
• Tier 3: Vec<Option<Box<CompactOverflowProps>>> — rare/complex (8 B/node)

Structs

CompactLayoutCache

Three-tier compact layout property cache.

CompactNodeProps

Compact numeric properties for a single node (96 bytes). All dimensions use MSB-sentinel encoding.

CompactTextProps

Compact text/IFC properties for a single node (24 bytes).

Constants

I16_AUTO

I16_INHERIT

I16_INITIAL

I16_SENTINEL

i16 sentinel values (for signed resolved-px ×10)

I16_SENTINEL_THRESHOLD

Any i16 value >= this threshold is a sentinel

U16_AUTO

U16_INHERIT

U16_INITIAL

U16_MAX_CONTENT

U16_MIN_CONTENT

U16_NONE

U16_SENTINEL

u16 sentinel values (for resolved-px ×10 and flex ×100)

U16_SENTINEL_THRESHOLD

Any u16 value >= this threshold is a sentinel, not a real value

U32_AUTO

U32_INHERIT

U32_INITIAL

U32_MAX_CONTENT

U32_MIN_CONTENT

U32_NONE

U32_SENTINEL

u32 sentinel values (for dimension properties with unit info)

U32_SENTINEL_THRESHOLD

Any u32 value >= this threshold is a sentinel

Functions

border_collapse_from_u8

border_collapse_to_u8

border_style_from_u8

border_style_to_u8

decode_align_content

decode_align_items

decode_border_bottom_style

Decode border-bottom-style from packed u16

decode_border_collapse

decode_border_left_style

Decode border-left-style from packed u16

decode_border_right_style

Decode border-right-style from packed u16

decode_border_top_style

Decode border-top-style from packed u16

decode_box_sizing

decode_clear

decode_color_u32

Decode a u32 back to ColorU. Returns None if sentinel (0x00000000).

decode_direction

decode_display

Decode individual enum properties from a Tier 1 u64. Each function is #[inline(always)] for zero-cost extraction.

decode_flex_direction

decode_flex_u16

Decode a u16 flex value back to f32. Returns None for sentinel values.

decode_flex_wrap

decode_float

decode_font_style

decode_font_weight

decode_justify_content

decode_overflow_x

decode_overflow_y

decode_pixel_value_u32

Decode a u32 back to PixelValue. Returns None for sentinel values.

decode_position

decode_resolved_px_i16

Decode an i16 back to resolved px. Returns None for sentinel values.

decode_text_align

decode_vertical_align

decode_visibility

decode_white_space

decode_writing_mode

encode_border_styles_packed

Encode 4 border styles into a u16: [3:0]=top, [7:4]=right, [11:8]=bottom, [15:12]=left

encode_color_u32

Encode a ColorU as u32 (0xRRGGBBAA). Returns 0 for sentinel/unset.

encode_css_pixel_as_i16

Resolve a CssPropertyValue to an i16 ×10 encoding. Only handles Exact(px(...)) values. Everything else → sentinel. For the compact cache builder, we only pre-resolve absolute pixel values. Relative units (em, %, etc.) get sentinel and fall back to the slow path.

encode_flex_u16

Encode a u16 flex value (×100). Returns U16_SENTINEL if out of range. Range: 0.00 ..= 655.27 at 0.01 precision.

encode_pixel_value_u32

u32 encoding for dimension properties (width, height, min-, max-, flex-basis, font-size).

encode_resolved_px_i16

Encode an i16 resolved px value (×10). Returns I16_SENTINEL if out of range. Range: -3276.8 ..= +3276.3 px at 0.1px precision.

encode_tier1

Pack all 21 enum properties into a single u64.

layout_align_content_from_u8

layout_align_content_to_u8

layout_align_items_from_u8

layout_align_items_to_u8

layout_box_sizing_from_u8

layout_box_sizing_to_u8

layout_clear_from_u8

layout_clear_to_u8

layout_display_from_u8

Convert raw bits back to LayoutDisplay. Returns default on invalid input.

layout_display_to_u8

Convert LayoutDisplay to its discriminant value (matching #[repr(C)] order).

layout_flex_direction_from_u8

layout_flex_direction_to_u8

layout_flex_wrap_from_u8

layout_flex_wrap_to_u8

layout_float_from_u8

layout_float_to_u8

layout_justify_content_from_u8

layout_justify_content_to_u8

layout_overflow_from_u8

layout_overflow_to_u8

layout_position_from_u8

layout_position_to_u8

layout_writing_mode_from_u8

layout_writing_mode_to_u8

size_metric_from_u8

u8 → SizeMetric

size_metric_to_u8

SizeMetric → u8 (4 bits, 12 variants)

style_direction_from_u8

style_direction_to_u8

style_font_style_from_u8

style_font_style_to_u8

style_font_weight_from_u8

style_font_weight_to_u8

style_text_align_from_u8

style_text_align_to_u8

style_vertical_align_from_u8

style_vertical_align_to_u8

style_visibility_from_u8

style_visibility_to_u8

style_white_space_from_u8

style_white_space_to_u8

tier1_is_populated

Returns true if the tier1 u64 was actually populated by encode_tier1.

Type Aliases

CompactOverflowProps

Overflow properties that couldn’t fit in Tier 1/2 encoding. Contains the original CssProperty values for properties that: