Initial commit

src/main/games/vdf.ts

@@ -0,0 +1,122 @@
+// Minimal Valve KeyValues (VDF) text parser.
+// Handles nested objects and quoted string values. Sufficient for libraryfolders.vdf.
+
+export type VdfNode = { [key: string]: string | VdfNode }
+
+class Cursor {
+  constructor(public src: string, public pos: number = 0) {}
+  peek(): string {
+    return this.src[this.pos] ?? ''
+  }
+  next(): string {
+    return this.src[this.pos++] ?? ''
+  }
+  eof(): boolean {
+    return this.pos >= this.src.length
+  }
+}
+
+function skipWhitespaceAndComments(c: Cursor): void {
+  for (;;) {
+    while (!c.eof() && /\s/.test(c.peek())) c.next()
+    if (c.peek() === '/' && c.src[c.pos + 1] === '/') {
+      while (!c.eof() && c.next() !== '\n') {
+        /* skip line */
+      }
+      continue
+    }
+    return
+  }
+}
+
+function readToken(c: Cursor): string {
+  skipWhitespaceAndComments(c)
+  if (c.eof()) return ''
+  if (c.peek() === '"') {
+    c.next()
+    let out = ''
+    while (!c.eof()) {
+      const ch = c.next()
+      if (ch === '\\') {
+        const next = c.next()
+        if (next === 'n') out += '\n'
+        else if (next === 't') out += '\t'
+        else out += next
+        continue
+      }
+      if (ch === '"') return out
+      out += ch
+    }
+    return out
+  }
+  if (c.peek() === '{' || c.peek() === '}') return c.next()
+  let out = ''
+  while (!c.eof() && !/\s/.test(c.peek()) && c.peek() !== '{' && c.peek() !== '}') {
+    out += c.next()
+  }
+  return out
+}
+
+function parseObject(c: Cursor): VdfNode {
+  const node: VdfNode = {}
+  for (;;) {
+    skipWhitespaceAndComments(c)
+    if (c.eof()) return node
+    if (c.peek() === '}') {
+      c.next()
+      return node
+    }
+    const key = readToken(c)
+    if (!key) return node
+    skipWhitespaceAndComments(c)
+    if (c.peek() === '{') {
+      c.next()
+      node[key] = parseObject(c)
+    } else {
+      node[key] = readToken(c)
+    }
+  }
+}
+
+export function parseVdf(src: string): VdfNode {
+  const c = new Cursor(src)
+  const root: VdfNode = {}
+  for (;;) {
+    skipWhitespaceAndComments(c)
+    if (c.eof()) break
+    const key = readToken(c)
+    if (!key) break
+    skipWhitespaceAndComments(c)
+    if (c.peek() === '{') {
+      c.next()
+      root[key] = parseObject(c)
+    } else {
+      root[key] = readToken(c)
+    }
+  }
+  return root
+}
+
+function escapeVdfString(s: string): string {
+  return s
+    .replace(/\\/g, '\\\\')
+    .replace(/"/g, '\\"')
+    .replace(/\n/g, '\\n')
+    .replace(/\t/g, '\\t')
+}
+
+export function stringifyVdf(node: VdfNode, indent: number = 0): string {
+  const pad = '\t'.repeat(indent)
+  let out = ''
+  for (const key of Object.keys(node)) {
+    const value = node[key]
+    if (typeof value === 'string') {
+      out += `${pad}"${escapeVdfString(key)}"\t\t"${escapeVdfString(value)}"\n`
+    } else {
+      out += `${pad}"${escapeVdfString(key)}"\n${pad}{\n`
+      out += stringifyVdf(value, indent + 1)
+      out += `${pad}}\n`
+    }
+  }
+  return out
+}