reflow_css_cascade.c File Reference

Content-CSS stylesheet scanner, cascade, and face lookup (#111). More...

#include <stddef.h>
#include <string.h>
#include "ra8_attributes.h"
#include "reflow.h"
#include "reflow_css.h"
#include "reflow_css_internal.h"

Include dependency graph for reflow_css_cascade.c:

Go to the source code of this file.

Enumerations
enum	priv_css_consts_t : uint16_t {   k_priv_rank_inherited = 0U ,   k_priv_spec_type = 1U ,   k_priv_spec_class = 100U ,   k_priv_spec_id = 10000U }
	Cascade specificity weights (packed id > class > type > universal). More...
enum	priv_css_scan_t : uint8_t { k_priv_cmt_marker = 2U }
	Token lengths used by the top-level stylesheet scanner. More...

Functions
ra8_err_t	ra8_css_sheet_reset (ra8_css_sheet_t *sheet)
	Reset a stylesheet to empty (no rules, no names, order 0).
static size_t	internal_skip_comment (const char *css, size_t len, size_t start)
	Step over a C-style comment starting at start.
static bool	internal_find_block (const char *css, size_t len, size_t i, size_t *out_open, size_t *out_close)
	Locate the { ... } block beginning at selector offset i.
ra8_err_t	ra8_css_parse (ra8_css_sheet_t *sheet, const char *css, uint32_t len)
	Parse one <style> block's CSS text, appending rules to sheet.
static bool	internal_class_list_has (const char *list, size_t list_len, const char *name, size_t nlen)
	True iff a space-separated class list contains name exactly.
bool	ra8_css_rule_matches (const ra8_css_rule_t *rule, const ra8_css_element_t *el, const ra8_css_sheet_t *sheet)
	Test whether rule rule's selector matches element el.
static bool	internal_anc_matches (const ra8_css_anc_t *anc, const ra8_css_element_t *el, const ra8_css_sheet_t *sheet)
	True if descendant ancestor part anc matches element el.
static bool	internal_rule_matches_ctx (const ra8_css_rule_t *rule, const ra8_css_element_t *el, const ra8_css_element_t *ancestors, uint8_t n_anc, const ra8_css_sheet_t *sheet)
	Full match of a (possibly descendant) rule against el + ancestors.
static uint16_t	internal_rule_rank (const ra8_css_rule_t *rule)
	Packed specificity (id*10000 + class*100 + type), summing all parts.
static const ra8_css_style_t *	internal_resolve (uint8_t setbit, const ra8_css_style_t *inherited, const ra8_css_sheet_t *sheet, const bool *matched, const ra8_css_style_t *inl)
	Resolve the winning declaration for one property across all sources.
static void	internal_cascade_emphasis (ra8_css_style_t *out, const ra8_css_sheet_t *sheet, const bool *matched, const ra8_css_style_t *inherited, const ra8_css_style_t *inl)
	Resolve the bold / italic / underline emphasis bits into out.
static void	internal_cascade_scalars (ra8_css_style_t *out, const ra8_css_sheet_t *sheet, const bool *matched, const ra8_css_style_t *inherited, const ra8_css_style_t *inl)
	Resolve the scalar properties (align / colour / font-size / display).
static void	internal_cascade_family (ra8_css_style_t *out, const ra8_css_sheet_t *sheet, const bool *matched, const ra8_css_style_t *inherited, const ra8_css_style_t *inl)
	Resolve the inherited font-family slice into out.
ra8_css_style_t	ra8_css_cascade_ctx (const ra8_css_sheet_t *sheet, const ra8_css_element_t *el, ra8_css_style_t inherited, ra8_css_style_t inline_decl, const ra8_css_element_t *ancestors, uint8_t n_anc)
	Compute an element's cascaded style with descendant-selector context.
ra8_css_style_t	ra8_css_cascade (const ra8_css_sheet_t *sheet, const ra8_css_element_t *el, ra8_css_style_t inherited, ra8_css_style_t inline_decl)
	Compute an element's cascaded style.
static bool	internal_ci_eq_span (const char *a, size_t alen, const char *b, size_t blen)
	Case-insensitive equality of two byte spans.
static bool	internal_family_eq (const ra8_css_sheet_t *sheet, const ra8_css_fontface_t *f, const char *family, size_t family_len)
	True iff face f's family equals family (case-insensitive).
int16_t	ra8_css_match_face (const ra8_css_sheet_t *sheet, const char *family, uint16_t family_len, bool want_bold, bool want_italic)
	Pick the @font-face whose family + emphasis best fits a run.
bool	ra8_css_face_src (const ra8_css_sheet_t *sheet, uint16_t idx, const char **out_src, uint16_t *out_len)
	Read a parsed @font-face entry's src href bytes.

Detailed Description

Content-CSS stylesheet scanner, cascade, and face lookup (#111).

The top-level stylesheet scanner (ra8_css_parse, comment + block skipping), the selector-matching and specificity cascade, and the @font-face lookup API for the v1 CSS subset documented in reflow_css.h. The scanner walks selector { ... } blocks and hands each to priv_reflow_css_parse_one_block in a sibling translation unit; the cascade resolves inherited / rule / inline sources into a single ra8_css_style_t. No MMIO, no heap; all state lives in the caller-owned ra8_css_sheet_t.

[Ring 4 / Reflow] {World: NS}

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since

0.1.0

Definition in file reflow_css_cascade.c.

Enumeration Type Documentation

priv_css_consts_t

enum priv_css_consts_t : uint16_t

Cascade specificity weights (packed id > class > type > universal).

A rule's specificity is the sum of one weight per present constraint (id + class + type), each at most 1 in our compound model; the packed value orders the cascade. Inheritance is the lowest priority (weight 0); a universal selector (no constraints) is also 0 but beats inheritance on source order.

Enumerator
k_priv_rank_inherited	Inheritance / universal weight.
k_priv_spec_type	A type constraint adds this.
k_priv_spec_class	A class constraint adds this.
k_priv_spec_id	An id constraint adds this.

Definition at line 45 of file reflow_css_cascade.c.

priv_css_scan_t

enum priv_css_scan_t : uint8_t

Token lengths used by the top-level stylesheet scanner.

Stand-ins for the / + * comment delimiters so the parse loop carries no bare numeric literals when stepping over comments and blocks.

Invariant

k_priv_cmt_marker is the byte count of / + * (or * + /).

See also

ra8_css_parse

Since

0.1.0

Enumerator
k_priv_cmt_marker	Byte length of a CSS comment delimiter pair.

Definition at line 63 of file reflow_css_cascade.c.

Function Documentation

internal_anc_matches()

bool internal_anc_matches ( const ra8_css_anc_t * anc, const ra8_css_element_t * el, const ra8_css_sheet_t * sheet )

static

True if descendant ancestor part anc matches element el.

Checks each non-zero constraint field of anc against el:

• tag: el->tag must equal anc->tag when the tag is not unknown.
• class_len: el->class_str must contain the interned class name via internal_class_list_has().
• id_len: el->id must equal the interned id byte for byte. Returns true only when all present constraints match. An anc with all fields zero (universal) always returns true.

Parameters

[in]	anc	Ancestor constraint part to test.
[in]	el	Element to test the constraint against.
[in]	sheet	Sheet owning the name pool for interned class/id names.

Returns

bool Whether anc matches el.

Return values

true	All constraints in anc are satisfied by el.
false	At least one constraint in anc is not satisfied.

Precondition

anc, el, and sheet are non-NULL.

Class/id offsets in anc are valid indices into sheet->names.

Postcondition

No state is mutated; the function is pure.

anc, el, and sheet are not modified.

Note

Thread-safe; pure function with no shared mutable state.

Since

0.1.0

Definition at line 320 of file reflow_css_cascade.c.

References ra8_css_anc_t::class_len, ra8_css_element_t::class_len, ra8_css_anc_t::class_off, ra8_css_element_t::class_str, ra8_css_element_t::id, ra8_css_anc_t::id_len, ra8_css_element_t::id_len, ra8_css_anc_t::id_off, internal_class_list_has(), k_reflow_tag_unknown, ra8_css_sheet_t::names, ra8_css_anc_t::tag, and ra8_css_element_t::tag.

Referenced by internal_rule_matches_ctx().

internal_cascade_emphasis()

void internal_cascade_emphasis ( ra8_css_style_t * out, const ra8_css_sheet_t * sheet, const bool * matched, const ra8_css_style_t * inherited, const ra8_css_style_t * inl )

static

Resolve the bold / italic / underline emphasis bits into out.

Iterates over a fixed table of three emphasis properties (bold, italic, underline) and calls internal_resolve() for each to find the winning style source. When a winner is found, the corresponding set bit is OR'd into out->set and the style bit is conditionally OR'd into out->style based on the winner's style field. The table has a statically known size of 3, making the loop provably bounded.

Parameters

[in,out]	out	Style record to write the resolved emphasis bits into.
[in]	sheet	Sheet providing the matching rules.
[in]	matched	Boolean array parallel to sheet->rules[]; true for each rule that matched the current element.
[in]	inherited	Style inherited from the parent element.
[in]	inl	Inline style from the element's style attribute.

Returns

Nothing.

Precondition

out, sheet, matched, inherited, and inl are non-NULL.

matched has at least sheet->rule_count elements.

Postcondition

out->set and out->style have the resolved emphasis bits written.

inherited and inl are not modified.

Note

Thread-safe with respect to distinct out instances.

Since

0.1.0

< Setbit.

< Stylebit.

Definition at line 531 of file reflow_css_cascade.c.

References internal_resolve(), k_ra8_css_set_bold, k_ra8_css_set_italic, k_ra8_css_set_underline, k_reflow_style_bold, k_reflow_style_italic, k_reflow_style_underline, ra8_css_style_t::set, and ra8_css_style_t::style.

Referenced by ra8_css_cascade_ctx().

internal_cascade_family()

void internal_cascade_family ( ra8_css_style_t * out, const ra8_css_sheet_t * sheet, const bool * matched, const ra8_css_style_t * inherited, const ra8_css_style_t * inl )

static

Resolve the inherited font-family slice into out.

Calls internal_resolve() for the k_ra8_css_set_family property and, when a winning style is found, copies (family_off, family_len) from the winner into out and OR's k_ra8_css_set_family into out->set. The family name itself lives in the sheet's name pool and is referenced by offset and length; no string copy is performed.

Parameters

[in,out]	out	Style record to write the resolved family reference into.
[in]	sheet	Sheet providing the matching rules and name pool.
[in]	matched	Boolean array parallel to sheet->rules[]; true for each rule that matched the current element.
[in]	inherited	Style inherited from the parent element.
[in]	inl	Inline style from the element's style attribute.

Returns

Nothing.

Precondition

out, sheet, matched, inherited, and inl are non-NULL.

matched has at least sheet->rule_count elements.

Postcondition

When a winning font-family source exists, out->family_off and out->family_len are set and k_ra8_css_set_family is OR'd into out->set.

inherited and inl are not modified.

Note

Thread-safe with respect to distinct out instances.

Since

0.1.0

Definition at line 649 of file reflow_css_cascade.c.

References ra8_css_style_t::family_len, ra8_css_style_t::family_off, internal_resolve(), k_ra8_css_set_family, and ra8_css_style_t::set.

Referenced by ra8_css_cascade_ctx().

internal_cascade_scalars()

void internal_cascade_scalars ( ra8_css_style_t * out, const ra8_css_sheet_t * sheet, const bool * matched, const ra8_css_style_t * inherited, const ra8_css_style_t * inl )

static

Resolve the scalar properties (align / colour / font-size / display).

Calls internal_resolve() for each of the four scalar CSS properties (text-align, color, font-size, display) and, when a winner is found, copies the winning value into out and OR's the corresponding set bit. font-size and display are resolved from rules and inline styles only; inheritance for those is handled by the caller to avoid double-application of percentage font-size values.

Parameters

[in,out]	out	Style record to write the resolved scalar values into.
[in]	sheet	Sheet providing the matching rules.
[in]	matched	Boolean array parallel to sheet->rules[]; true for each rule that matched the current element.
[in]	inherited	Style inherited from the parent element.
[in]	inl	Inline style from the element's style attribute.

Returns

Nothing.

Precondition

out, sheet, matched, inherited, and inl are non-NULL.

matched has at least sheet->rule_count elements.

Postcondition

out reflects the winning scalar values for all four properties.

inherited and inl are not modified.

Note

Thread-safe with respect to distinct out instances.

Since

0.1.0

Definition at line 585 of file reflow_css_cascade.c.

References ra8_css_style_t::align, ra8_css_style_t::color, ra8_css_style_t::display, ra8_css_style_t::font_unit, ra8_css_style_t::font_val, internal_resolve(), k_ra8_css_set_align, k_ra8_css_set_color, k_ra8_css_set_display, k_ra8_css_set_fontsize, and ra8_css_style_t::set.

Referenced by ra8_css_cascade_ctx().

internal_ci_eq_span()

bool internal_ci_eq_span ( const char * a, size_t alen, const char * b, size_t blen )

static

Case-insensitive equality of two byte spans.

Compares a[0..alen) and b[0..blen) byte-by-byte after ASCII case-folding via priv_reflow_css_lower(). Returns false immediately when either pointer is NULL or the lengths differ. The comparison loop is bounded by alen (which equals blen when lengths match).

Parameters

[in]	a	First byte span (need not be NUL-terminated).
[in]	alen	Length of a in bytes.
[in]	b	Second byte span (need not be NUL-terminated).
[in]	blen	Length of b in bytes.

Returns

bool Comparison result.

Return values

true	Both spans have equal length and compare equal case-insensitively.
false	Either pointer is NULL, lengths differ, or any byte differs.

Precondition

a points to at least alen readable bytes, or is NULL.

b points to at least blen readable bytes, or is NULL.

Postcondition

No state is mutated; the function is pure.

a and b are not modified.

Note

Thread-safe; pure function with no shared state.

Since

0.1.0

Definition at line 720 of file reflow_css_cascade.c.

References priv_reflow_css_lower().

Referenced by internal_family_eq().

internal_class_list_has()

bool internal_class_list_has ( const char * list, size_t list_len, const char * name, size_t nlen )

static

True iff a space-separated class list contains name exactly.

Tokenises list[0..list_len) on whitespace and performs a byte-exact (not case-folded) comparison of each token against name[0..nlen), byte by byte. The outer loop is bounded by list_len; each pass skips leading whitespace, extracts the next token, and compares it. Returns true on the first matching token; false if no token matches.

Parameters

[in]	list	Space-separated class attribute value span.
[in]	list_len	Number of bytes in list.
[in]	name	Interned class name to search for.
[in]	nlen	Length of name in bytes.

Returns

bool Search result.

Return values

true	At least one whitespace-delimited token in list equals name.
false	No token in list matches name, or list is empty.

Precondition

list points to at least list_len readable bytes.

name points to at least nlen readable bytes.

Postcondition

No state is mutated; the function is pure.

list and name are not modified.

Note

Thread-safe; pure function with no shared state.

Since

0.1.0

Definition at line 233 of file reflow_css_cascade.c.

References priv_reflow_css_is_ws().

Referenced by internal_anc_matches(), and ra8_css_rule_matches().

internal_family_eq()

bool internal_family_eq ( const ra8_css_sheet_t * sheet, const ra8_css_fontface_t * f, const char * family, size_t family_len )

static

True iff face f's family equals family (case-insensitive).

Retrieves the interned family name from sheet->names using f->family_off and f->family_len, then delegates to internal_ci_eq_span() for a case-insensitive comparison against family[0..family_len).

Parameters

[in]	sheet	Sheet owning the name pool referenced by f.
[in]	f	Font face whose interned family name to compare.
[in]	family	Byte span of the family name to match.
[in]	family_len	Number of bytes in family.

Returns

bool Comparison result.

Return values

true	f's interned family name equals family case-insensitively.
false	The names differ in length or any byte differs.

Precondition

sheet and f are non-NULL.

f->family_off + f->family_len <= sheet->names_used.

Postcondition

No state is mutated; the function is pure relative to sheet.

family is not modified.

Note

Thread-safe; no shared mutable state.

Since

0.1.0

Definition at line 760 of file reflow_css_cascade.c.

References ra8_css_fontface_t::family_len, ra8_css_fontface_t::family_off, internal_ci_eq_span(), and ra8_css_sheet_t::names.

Referenced by ra8_css_match_face().

internal_find_block()

bool internal_find_block ( const char * css, size_t len, size_t i, size_t * out_open, size_t * out_close )

static

Locate the { ... } block beginning at selector offset i.

Scans forward for the block-open byte, then the block-close byte, writing both offsets out. Returns false when no block-open is present, which the caller treats as end-of-input.

Parameters

[in]	css	Stylesheet text (non-NULL, validated by the caller).
[in]	len	Total length of css, bytes.
[in]	i	Offset of the selector list start.
[out]	out_open	Offset of the block-open byte (valid only on true).
[out]	out_close	Offset of the block-close byte, or len if missing.

Returns

True iff a block-open byte was found at or after i.

Return values

true	A block-open was found; out_open / out_close are set.
false	No block-open exists in [i, len).

Precondition

css, out_open, out_close are non-NULL.

i <= len.

Postcondition

On true, *out_open < len and *out_close <= len.

No state other than the out-params is mutated.

Note

Thread-safe; operates on caller-owned memory only.

Since

0.1.0

Definition at line 145 of file reflow_css_cascade.c.

Referenced by ra8_css_parse().

internal_resolve()

const ra8_css_style_t * internal_resolve ( uint8_t setbit, const ra8_css_style_t * inherited, const ra8_css_sheet_t * sheet, const bool * matched, const ra8_css_style_t * inl )

static

Resolve the winning declaration for one property across all sources.

Returns

Pointer to the winning style (inherited / a rule decl / inline), or NULL if no source declares setbit.

Definition at line 467 of file reflow_css_cascade.c.

References ra8_css_rule_t::decl, internal_rule_rank(), k_priv_rank_inherited, ra8_css_rule_t::order, ra8_css_sheet_t::rule_count, ra8_css_sheet_t::rules, and ra8_css_style_t::set.

Referenced by internal_cascade_emphasis(), internal_cascade_family(), and internal_cascade_scalars().

internal_rule_matches_ctx()

bool internal_rule_matches_ctx ( const ra8_css_rule_t * rule, const ra8_css_element_t * el, const ra8_css_element_t * ancestors, uint8_t n_anc, const ra8_css_sheet_t * sheet )

static

Full match of a (possibly descendant) rule against el + ancestors.

The subject must match el via ra8_css_rule_matches(); when rule->anc_count is 0 that check is sufficient. For rules with ancestor constraints, a greedy right-to-left scan walks the ancestor stack from innermost (ancestors[n_anc-1]) to outermost (ancestors[0]), consuming one rule ancestor part per stack element that matches via internal_anc_matches(). The descendant combinator allows any depth between parts. Returns true only when all ancestor parts are consumed (ai < 0 at loop exit).

Parameters

[in]	rule	Rule to match (subject + ancestor constraints).
[in]	el	Subject element to match the rule's subject compound.
[in]	ancestors	Array of ancestor elements; index 0 is outermost.
[in]	n_anc	Number of elements in ancestors.
[in]	sheet	Sheet owning the name pool for interned names.

Returns

bool Whether the rule matches the element in context.

Return values

true	The rule's subject and all ancestor constraints are satisfied.
false	The subject does not match el, or at least one ancestor constraint has no matching ancestor in the stack.

Precondition

rule, el, and sheet are non-NULL.

ancestors points to at least n_anc readable elements, or is NULL when n_anc is 0.

Postcondition

No state is mutated; the function is pure.

rule, el, ancestors, and sheet are not modified.

Note

Thread-safe; pure function with no shared mutable state.

Since

0.1.0

Definition at line 381 of file reflow_css_cascade.c.

References ra8_css_rule_t::anc, ra8_css_rule_t::anc_count, internal_anc_matches(), and ra8_css_rule_matches().

Referenced by ra8_css_cascade_ctx().

internal_rule_rank()

uint16_t internal_rule_rank ( const ra8_css_rule_t * rule )

static

Packed specificity (id*10000 + class*100 + type), summing all parts.

Computes the CSS cascade specificity of rule by summing weights for each present constraint across the subject and all ancestor parts:

• k_priv_spec_id (10000) for each non-empty id field.
• k_priv_spec_class (100) for each non-empty class field.
• k_priv_spec_type (1) for each non-unknown tag. The ancestor loop is bounded by rule->anc_count. The result is used by internal_resolve() to determine which rule wins during the cascade.

Parameters

[in]

rule

Rule whose specificity to compute.

Returns

uint16_t Packed specificity value.

Return values

0	When no type, class, or id constraints are present (universal).
>0	The summed specificity per CSS cascade rules.

Precondition

rule is non-NULL.

rule->anc_count is accurate (within bounds of rule->anc[]).

Postcondition

No state is mutated; the function is pure.

rule is not modified.

Note

Thread-safe; pure function with no shared state.

Since

0.1.0

Definition at line 433 of file reflow_css_cascade.c.

References ra8_css_rule_t::anc, ra8_css_rule_t::anc_count, ra8_css_anc_t::class_len, ra8_css_rule_t::class_len, ra8_css_anc_t::id_len, ra8_css_rule_t::id_len, k_priv_spec_class, k_priv_spec_id, k_priv_spec_type, k_reflow_tag_unknown, ra8_css_rule_t::sel_tag, and ra8_css_anc_t::tag.

Referenced by internal_resolve().

internal_skip_comment()

size_t internal_skip_comment ( const char * css, size_t len, size_t start )

static

Step over a C-style comment starting at start.

Assumes css[start..start+1] is the open delimiter and scans to the matching close delimiter, returning the offset just past it (clamped to len when the comment is unterminated).

Parameters

[in]	css	Stylesheet text (non-NULL, validated by the caller).
[in]	len	Total length of css, bytes.
[in]	start	Offset of the comment open delimiter.

Returns

Offset of the first byte after the comment, in [start, len].

Return values

len	The comment ran to the end of the buffer (unterminated).

Precondition

css is non-NULL.

start < len.

Postcondition

The return value is in [start, len].

No state is mutated (pure function).

Note

Thread-safe; operates on caller-owned memory only.

Since

0.1.0

Definition at line 106 of file reflow_css_cascade.c.

References k_priv_cmt_marker.

Referenced by ra8_css_parse().

ra8_css_cascade()

ra8_css_style_t ra8_css_cascade ( const ra8_css_sheet_t * sheet, const ra8_css_element_t * el, ra8_css_style_t inherited, ra8_css_style_t inline_decl )

nodiscard

Compute an element's cascaded style.

Folds, in increasing priority: inherited (inheritable properties only), every matching rule in sheet by (specificity, source order), then inline_decl (always wins). Each property resolves independently to its highest-priority setter.

Parameters

[in]	sheet	Parsed stylesheet (may be empty).
[in]	el	Element identity.
[in]	inherited	Parent's computed style (inheritable props flow in).
[in]	inline_decl	Inline style="" declaration (set == 0 if none).

Returns

The computed ra8_css_style_t for el.

Precondition

sheet, el non-NULL (NULL sheet/el -> returns inherited).

None.

Postcondition

Every property bit in the result was set by the winning source.

Note

Pure; thread-safe.

Since

0.1.0

Definition at line 686 of file reflow_css_cascade.c.

References ra8_css_cascade_ctx().

ra8_css_cascade_ctx()

ra8_css_style_t ra8_css_cascade_ctx ( const ra8_css_sheet_t * sheet, const ra8_css_element_t * el, ra8_css_style_t inherited, ra8_css_style_t inline_decl, const ra8_css_element_t * ancestors, uint8_t n_anc )

nodiscard

Compute an element's cascaded style with descendant-selector context.

Identical to ra8_css_cascade but also resolves descendant selectors (.chapter p, div p): a rule with ancestor parts matches only when its subject matches el AND each ancestor part matches some element in ancestors (the open-element stack, outermost first), in order. ra8_css_cascade is the n_anc == 0 case (descendant rules never match without ancestor context). Each matched ancestor part also adds to the rule's specificity.

Parameters

[in]	sheet	Parsed stylesheet (may be empty).
[in]	el	Element identity (the selector subject).
[in]	inherited	Parent's computed style (inheritable props flow in).
[in]	inline_decl	Inline style="" declaration (set == 0 if none).
[in]	ancestors	Open-element ancestors, outermost (root) first; may be NULL iff n_anc is 0.
[in]	n_anc	Number of entries in ancestors (0 = no context).

Returns

The computed ra8_css_style_t for el.

Precondition

sheet, el non-NULL (NULL -> returns inherited).

ancestors non-NULL when n_anc > 0.

Postcondition

Every property bit in the result was set by the winning source.

Note

Pure; thread-safe.

Since

0.1.0

Definition at line 664 of file reflow_css_cascade.c.

References internal_cascade_emphasis(), internal_cascade_family(), internal_cascade_scalars(), internal_rule_matches_ctx(), k_ra8_css_max_rules, ra8_css_sheet_t::rule_count, and ra8_css_sheet_t::rules.

Referenced by internal_open_styled(), and ra8_css_cascade().

ra8_css_face_src()

bool ra8_css_face_src ( const ra8_css_sheet_t * sheet, uint16_t idx, const char ** out_src, uint16_t * out_len )

nodiscard

Read a parsed @font-face entry's src href bytes.

Returns the de-url()-wrapped manifest href slice for face idx (the value ra8_css_match_face's result indexes), so the caller can resolve it against the EPUB manifest. The bytes live in sheet's name pool and are valid for the sheet's lifetime; they are not NUL-terminated.

Parameters

[in]	sheet	Parsed stylesheet owning the face table.
[in]	idx	Face index in [0, face_count).
[out]	out_src	Receives a pointer to the href bytes.
[out]	out_len	Receives the href length, bytes.

Returns

true iff idx is valid and the href was returned.

Return values

false

A NULL pointer, or idx out of range.

Precondition

sheet, out_src, out_len non-NULL.

None.

Postcondition

On true, *out_src/*out_len describe the face's href; else unchanged.

Note

Pure; thread-safe.

Since

0.1.0

Definition at line 799 of file reflow_css_cascade.c.

References ra8_css_sheet_t::face_count, ra8_css_sheet_t::faces, ra8_css_sheet_t::names, ra8_css_fontface_t::src_len, and ra8_css_fontface_t::src_off.

ra8_css_match_face()

int16_t ra8_css_match_face ( const ra8_css_sheet_t * sheet, const char * family, uint16_t family_len, bool want_bold, bool want_italic )

nodiscard

Pick the @font-face whose family + emphasis best fits a run.

Scans sheet's parsed @font-face table for entries whose font-family equals family (case-insensitive, exact). Among those it prefers an exact (weight, style) match; failing that it falls back to the family's regular (non-bold, non-italic) face; failing that it reports k_ra8_css_no_face so the caller uses its default face. This is the face-selection decision #109's remainder consumes (it then resolves the winning entry's ra8_css_face_src href to a loaded typeface).

Parameters

[in]	sheet	Parsed stylesheet (its faces table is scanned).
[in]	family	Resolved font-family bytes (e.g. a cascade result's name slice); need not be NUL-terminated.
[in]	family_len	Length of family, bytes.
[in]	want_bold	Whether the run is bold.
[in]	want_italic	Whether the run is italic.

Returns

The matching faces index in [0, face_count), or k_ra8_css_no_face.

Precondition

sheet, family non-NULL and family_len > 0 (else no match).

None.

Postcondition

No state modified.

Note

Pure; thread-safe.

Since

0.1.0

Definition at line 771 of file reflow_css_cascade.c.

References ra8_css_sheet_t::face_count, ra8_css_sheet_t::faces, internal_family_eq(), k_ra8_css_no_face, ra8_css_fontface_t::style_italic, and ra8_css_fontface_t::weight_bold.

Referenced by priv_reflow_tok_resolve_face_slot().

ra8_css_parse()

ra8_err_t ra8_css_parse ( ra8_css_sheet_t * sheet, const char * css, uint32_t len )

nodiscard

Parse one <style> block's CSS text, appending rules to sheet.

Handles /<star> comments <star>/, comma-grouped simple selectors, and the v1 property set. Unsupported selectors (compound / descendant / pseudo) and unknown properties are skipped, not errored. Rules beyond k_ra8_css_max_rules (or names beyond the pool) are dropped silently.

Parameters

[in,out]	sheet	Stylesheet to grow.
[in]	css	CSS source bytes (a <style> block body).
[in]	len	Length of css, bytes.

Returns

ra8_err_t

Return values

k_ra8_ok	Parsed (possibly with truncation).
k_ra8_err_null_ptr	sheet or css is NULL.

Precondition

sheet, css non-NULL.

None.

Postcondition

New rules (if any room) are appended with ascending order.

sheet->rule_count never exceeds k_ra8_css_max_rules.

Note

Pure aside from writing sheet.

Since

0.1.0

Definition at line 167 of file reflow_css_cascade.c.

References internal_find_block(), internal_skip_comment(), k_ra8_err_null_ptr, k_ra8_ok, priv_reflow_css_is_ws(), and priv_reflow_css_parse_one_block().

Referenced by internal_handle_link(), and internal_handle_raw_text().

ra8_css_rule_matches()

bool ra8_css_rule_matches ( const ra8_css_rule_t * rule, const ra8_css_element_t * el, const ra8_css_sheet_t * sheet )

nodiscard

Test whether rule rule's selector matches element el.

Parameters

[in]	rule	Rule whose selector is tested.
[in]	el	Element identity (tag + id + class list).
[in]	sheet	Sheet owning the rule's name pool.

Returns

true iff the simple selector matches el.

Return values

false

A required pointer is NULL, or the selector does not match.

Precondition

rule, el, sheet non-NULL (NULL -> false).

None.

Postcondition

No state modified.

Note

Pure; thread-safe.

Since

0.1.0

Definition at line 259 of file reflow_css_cascade.c.

References ra8_css_element_t::class_len, ra8_css_rule_t::class_len, ra8_css_rule_t::class_off, ra8_css_element_t::class_str, ra8_css_element_t::id, ra8_css_element_t::id_len, ra8_css_rule_t::id_len, ra8_css_rule_t::id_off, internal_class_list_has(), k_reflow_tag_unknown, ra8_css_sheet_t::names, ra8_css_rule_t::sel_tag, and ra8_css_element_t::tag.

Referenced by internal_rule_matches_ctx().

ra8_css_sheet_reset()

ra8_err_t ra8_css_sheet_reset ( ra8_css_sheet_t * sheet )

nodiscard

Reset a stylesheet to empty (no rules, no names, order 0).

Parameters

[out]

sheet

Stylesheet to clear.

Returns

ra8_err_t

Return values

k_ra8_ok	Cleared.
k_ra8_err_null_ptr	sheet is NULL.

Precondition

sheet is non-NULL.

None.

Postcondition

sheet->rule_count == 0 and sheet->names_used == 0.

sheet->next_order == 0.

Note

Pure aside from writing sheet; not thread-safe relative to it.

Since

0.1.0

Definition at line 72 of file reflow_css_cascade.c.

References ra8_css_sheet_t::face_count, k_ra8_err_null_ptr, k_ra8_ok, ra8_css_sheet_t::names_used, ra8_css_sheet_t::next_order, and ra8_css_sheet_t::rule_count.

Referenced by priv_reflow_xml_walk().