68 lines
1.4 KiB
TypeScript
68 lines
1.4 KiB
TypeScript
/**
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* ESC Sequence Parser
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*
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* Handles simple escape sequences: ESC + one or two characters
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*/
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import type { Action } from './types.js'
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/**
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* Parse a simple ESC sequence
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*
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* @param chars - Characters after ESC (not including ESC itself)
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*/
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export function parseEsc(chars: string): Action | null {
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if (chars.length === 0) return null
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const first = chars[0]!
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// Full reset (RIS)
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if (first === 'c') {
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return { type: 'reset' }
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}
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// Cursor save (DECSC)
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if (first === '7') {
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return { type: 'cursor', action: { type: 'save' } }
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}
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// Cursor restore (DECRC)
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if (first === '8') {
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return { type: 'cursor', action: { type: 'restore' } }
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}
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// Index - move cursor down (IND)
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if (first === 'D') {
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return {
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type: 'cursor',
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action: { type: 'move', direction: 'down', count: 1 },
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}
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}
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// Reverse index - move cursor up (RI)
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if (first === 'M') {
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return {
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type: 'cursor',
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action: { type: 'move', direction: 'up', count: 1 },
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}
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}
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// Next line (NEL)
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if (first === 'E') {
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return { type: 'cursor', action: { type: 'nextLine', count: 1 } }
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}
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// Horizontal tab set (HTS)
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if (first === 'H') {
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return null // Tab stop, not commonly needed
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}
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// Charset selection (ESC ( X, ESC ) X, etc.) - silently ignore
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if ('()'.includes(first) && chars.length >= 2) {
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return null
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}
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// Unknown
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return { type: 'unknown', sequence: `\x1b${chars}` }
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}
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