tiny.zen.FrontmatterPlan

1pub const Plan = struct {2    input_bytes: usize,3    metadata_start: usize,4    metadata_end: usize,5    body_start: usize,6    pairs: usize,7    continuation_bytes: usize,8    projection: MetadataProjection,910    pub fn inspect(markdown: []const u8, limits: Limits) model.Error!Plan {11        const split = try scan.sections(markdown);12        std.debug.assert(split.metadata_start <= split.metadata_end);13        std.debug.assert(split.metadata_end <= split.body_start);14        std.debug.assert(split.body_start <= markdown.len);15        var iterator = scan.Iterator.init(markdown[split.metadata_start..split.metadata_end]);16        var pair_count: usize = 0;17        var finalized_bytes: usize = 0;18        var current: ?Current = null;19        var projection: Projection = .{};2021        while (iterator.next()) |field| switch (field) {22            .pair => |pair| {23                finalized_bytes = try finalize(finalized_bytes, current);24                projection.finish(current);25                pair_count = try added(pair_count, 1);26                if (pair_count > limits.max_pairs) return error.PairCapacityExceeded;27                current = Current.init(pair.key, pair.value);28            },29            .continuation => |value| if (current) |*active| {30                try active.continueWith(value);31                const admitted = try added(finalized_bytes, active.joined_bytes);32                if (admitted > limits.max_continuation_bytes) {33                    return error.ContinuationByteCapacityExceeded;34                }35            },36        };37        finalized_bytes = try finalize(finalized_bytes, current);38        projection.finish(current);39        std.debug.assert(pair_count <= limits.max_pairs);40        std.debug.assert(finalized_bytes <= limits.max_continuation_bytes);41        const result = Plan{42            .input_bytes = markdown.len,43            .metadata_start = split.metadata_start,44            .metadata_end = split.metadata_end,45            .body_start = split.body_start,46            .pairs = pair_count,47            .continuation_bytes = finalized_bytes,48            .projection = projection.value,49        };50        std.debug.assert(result.input_bytes == markdown.len);51        std.debug.assert(result.pairs == pair_count);52        std.debug.assert(result.continuation_bytes == finalized_bytes);53        return result;54    }5556    pub fn exactLimits(self: Plan) Limits {57        const limits = Limits{58            .max_pairs = self.pairs,59            .max_continuation_bytes = self.continuation_bytes,60        };61        std.debug.assert(limits.max_pairs == self.pairs);62        std.debug.assert(limits.max_continuation_bytes == self.continuation_bytes);63        return limits;64    }65};

1/// Exact frontmatter demand and common-field projection measured without allocation.2pub const FrontmatterPlan = frontmatter.Plan;