flow/src/buffer/Cursor.zig

240 lines
8 KiB
Zig

const std = @import("std");
const cbor = @import("cbor");
const Buffer = @import("Buffer.zig");
const View = @import("View.zig");
const Selection = @import("Selection.zig");
const Metrics = Buffer.Metrics;
row: usize = 0,
col: usize = 0,
target: usize = 0,
const Self = @This();
pub inline fn invalid() Self {
return .{
.row = std.math.maxInt(u32),
.col = std.math.maxInt(u32),
.target = std.math.maxInt(u32),
};
}
pub inline fn eql(self: Self, other: Self) bool {
return self.row == other.row and self.col == other.col;
}
pub inline fn right_of(self: Self, other: Self) bool {
return if (self.row > other.row) true else if (self.row == other.row and self.col > other.col) true else false;
}
pub fn clamp_to_buffer(self: *Self, root: Buffer.Root, metrics: Metrics) void {
self.row = @min(self.row, root.lines() - 1);
self.col = @min(self.col, root.line_width(self.row, metrics) catch 0);
}
fn follow_target(self: *Self, root: Buffer.Root, metrics: Metrics) void {
self.col = @min(self.target, root.line_width(self.row, metrics) catch 0);
}
fn move_right_no_target(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
const lines = root.lines();
if (lines <= self.row) return error.Stop;
if (self.col < root.line_width(self.row, metrics) catch 0) {
_, const wcwidth, const offset = root.ecg_at(self.row, self.col, metrics) catch return error.Stop;
self.col += wcwidth - offset;
} else if (self.row < lines - 1) {
self.col = 0;
self.row += 1;
} else return error.Stop;
}
pub fn move_right(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
try self.move_right_no_target(root, metrics);
self.target = self.col;
}
fn move_left_no_target(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
if (self.col == 0) {
if (self.row == 0) return error.Stop;
self.row -= 1;
self.col = root.line_width(self.row, metrics) catch 0;
} else {
_, const wcwidth, _ = root.ecg_at(self.row, self.col - 1, metrics) catch return error.Stop;
if (self.col > wcwidth) self.col -= wcwidth else self.col = 0;
}
}
pub fn move_left(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
try self.move_left_no_target(root, metrics);
self.target = self.col;
}
pub fn move_up(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
if (self.row > 0) {
self.row -= 1;
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
try self.move_right_no_target(root, metrics);
} else return error.Stop;
}
pub fn move_down(self: *Self, root: Buffer.Root, metrics: Metrics) !void {
if (self.row < root.lines() - 1) {
self.row += 1;
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
try self.move_right_no_target(root, metrics);
} else return error.Stop;
}
pub fn move_page_up(self: *Self, root: Buffer.Root, view: *const View, metrics: Metrics) void {
self.row = if (self.row > view.rows) self.row - view.rows else 0;
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
self.move_right_no_target(root, metrics) catch return;
}
pub fn move_page_down(self: *Self, root: Buffer.Root, view: *const View, metrics: Metrics) void {
if (root.lines() > self.row + view.rows) {
self.row += view.rows;
} else self.move_buffer_last(root, metrics);
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
self.move_right_no_target(root, metrics) catch return;
}
pub fn move_half_page_up(self: *Self, root: Buffer.Root, view: *const View, metrics: Metrics) void {
const half_view_rows = @divTrunc(view.rows, 2);
self.row = if (self.row > half_view_rows) self.row - half_view_rows else 0;
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
self.move_right_no_target(root, metrics) catch return;
}
pub fn move_half_page_down(self: *Self, root: Buffer.Root, view: *const View, metrics: Metrics) void {
const half_view_rows = @divTrunc(view.rows, 2);
if (root.lines() > self.row + half_view_rows) {
self.row += half_view_rows;
} else self.move_buffer_last(root, metrics);
self.follow_target(root, metrics);
self.move_left_no_target(root, metrics) catch return;
self.move_right_no_target(root, metrics) catch return;
}
pub fn move_to(self: *Self, root: Buffer.Root, row: usize, col: usize, metrics: Metrics) !void {
if (row < root.lines()) {
self.row = row;
self.col = @min(col, root.line_width(self.row, metrics) catch return error.Stop);
self.target = self.col;
} else return error.Stop;
}
pub fn move_abs(self: *Self, root: Buffer.Root, v: *View, y: usize, x: usize, metrics: Metrics) !void {
self.row = v.row + y;
self.col = v.col + x;
self.clamp_to_buffer(root, metrics);
self.target = self.col;
}
pub fn move_begin(self: *Self) void {
self.col = 0;
self.target = self.col;
}
pub fn move_end(self: *Self, root: Buffer.Root, metrics: Metrics) void {
if (self.row < root.lines()) self.col = root.line_width(self.row, metrics) catch 0;
self.target = std.math.maxInt(u32);
}
pub fn move_buffer_begin(self: *Self) void {
self.row = 0;
self.col = 0;
self.target = 0;
}
pub fn move_buffer_end(self: *Self, root: Buffer.Root, metrics: Metrics) void {
self.row = root.lines() - 1;
self.move_end(root, metrics);
if (self.col == 0) self.target = 0;
}
fn move_buffer_first(self: *Self, root: Buffer.Root, metrics: Metrics) void {
self.row = 0;
self.follow_target(root, metrics);
}
fn move_buffer_last(self: *Self, root: Buffer.Root, metrics: Metrics) void {
self.row = root.lines() - 1;
self.follow_target(root, metrics);
}
fn is_at_begin(self: *const Self) bool {
return self.col == 0;
}
fn is_at_end(self: *const Self, root: Buffer.Root, metrics: Metrics) bool {
return if (self.row < root.lines()) self.col == root.line_width(self.row, metrics) catch 0 else true;
}
pub fn test_at(self: *const Self, root: Buffer.Root, pred: *const fn (c: []const u8) bool, metrics: Metrics) bool {
return root.test_at(pred, self.row, self.col, metrics);
}
pub fn write(self: *const Self, writer: Buffer.MetaWriter) !void {
try cbor.writeValue(writer, .{
self.row,
self.col,
self.target,
});
}
pub fn extract(self: *Self, iter: *[]const u8) !bool {
return cbor.matchValue(iter, .{
cbor.extract(&self.row),
cbor.extract(&self.col),
cbor.extract(&self.target),
});
}
pub fn nudge_insert(self: *Self, nudge: Selection) void {
if (self.row < nudge.begin.row or (self.row == nudge.begin.row and self.col < nudge.begin.col)) return;
const rows = nudge.end.row - nudge.begin.row;
if (self.row == nudge.begin.row) {
if (nudge.begin.row < nudge.end.row) {
self.row += rows;
self.col = self.col - nudge.begin.col + nudge.end.col;
} else {
self.col += nudge.end.col - nudge.begin.col;
}
} else {
self.row += rows;
}
self.target = self.col;
}
pub fn nudge_delete(self: *Self, nudge: Selection) bool {
if (self.row < nudge.begin.row or (self.row == nudge.begin.row and self.col < nudge.begin.col)) return true;
if (self.row == nudge.begin.row) {
if (nudge.begin.row < nudge.end.row) {
return false;
} else {
if (self.col < nudge.end.col) {
return false;
}
self.col -= nudge.end.col - nudge.begin.col;
self.target = self.col;
return true;
}
}
if (self.row < nudge.end.row) return false;
if (self.row == nudge.end.row) {
if (self.col < nudge.end.col) return false;
self.row -= nudge.end.row - nudge.begin.row;
self.col -= nudge.end.col;
self.target = self.col;
return true;
}
self.row -= nudge.end.row - nudge.begin.row;
return true;
}