rock-n-code/playdate-kit
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Remove per-call overhead from API access and text conversion

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Two hot-path optimizations for the device's Cortex-M7 (and debug simulator
builds):

- The ten sub-API pointers are cached once in Playdate.initialize(with:);
  wrapper accessors now return UnsafePointer and call sites read a single
  field through it, instead of unwrapping the optional API struct and
  copying a whole sub-API struct of function pointers on every call.
  Nested sub-APIs (sound classes, effects, video, tilemap, http/tcp)
  derive from the cached pointers with one field load.

- String -> C conversions (withPlaydateCString, and a new withPlaydateUTF8
  used by the text drawing/measuring APIs) use withUnsafeTemporaryAllocation
  instead of building a ContiguousArray, so logging and drawText in the
  update loop no longer heap-allocate per call. Verified within the
  Embedded Swift subset by the device cross-compile.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
javier
2026-07-25 07:23:19 +02:00
co-authored by Claude Fable 5
parent e4e99cc894
commit d914e0f8fb
20 changed files with 682 additions and 643 deletions
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Sources/PlayDate/File.swift
+17 -17
View File
@@ -8,11 +8,11 @@
internal import CPlaydate
private var fileAPI: playdate_file { Playdate.api.file.pointee }
private var fileAPI: UnsafePointer<playdate_file> { Playdate.fileAPI }
/// The most recent file system error as a thrown error.
private func lastFileError() -> PlaydateError {
PlaydateError(cString: fileAPI.geterr.unsafelyUnwrapped())
PlaydateError(cString: fileAPI.pointee.geterr.unsafelyUnwrapped())
}
/// The file API: access to the game's Data directory and pdx contents.
@@ -62,7 +62,7 @@ extension File {
var callback = each
return path.withPlaydateCString { cPath in
withUnsafeMutablePointer(to: &callback) { callbackPointer in
fileAPI.listfiles.unsafelyUnwrapped(cPath, { cName, userdata in
fileAPI.pointee.listfiles.unsafelyUnwrapped(cPath, { cName, userdata in
guard let cName, let userdata else { return }
let each = userdata.assumingMemoryBound(to: ((String) -> Void).self).pointee
each(String(playdateCString: cName))
@@ -76,7 +76,7 @@ extension File {
/// Information about the file or directory at `path`.
public static func stat(_ path: String) throws(PlaydateError) -> Stat {
var stat = FileStat()
let result = path.withPlaydateCString { fileAPI.stat.unsafelyUnwrapped($0, &stat) }
let result = path.withPlaydateCString { fileAPI.pointee.stat.unsafelyUnwrapped($0, &stat) }
if result != 0 { throw lastFileError() }
return Stat(
isDirectory: stat.isdir != 0,
@@ -88,7 +88,7 @@ extension File {
/// Creates a directory (and intermediate directories) in the Data directory.
public static func mkdir(_ path: String) throws(PlaydateError) {
let result = path.withPlaydateCString { fileAPI.mkdir.unsafelyUnwrapped($0) }
let result = path.withPlaydateCString { fileAPI.pointee.mkdir.unsafelyUnwrapped($0) }
if result != 0 { throw lastFileError() }
}
@@ -96,7 +96,7 @@ extension File {
/// `recursive` to be deleted with their contents.
public static func unlink(_ path: String, recursive: Bool = false) throws(PlaydateError) {
let result = path.withPlaydateCString {
fileAPI.unlink.unsafelyUnwrapped($0, recursive ? 1 : 0)
fileAPI.pointee.unlink.unsafelyUnwrapped($0, recursive ? 1 : 0)
}
if result != 0 { throw lastFileError() }
}
@@ -106,7 +106,7 @@ extension File {
public static func rename(from: String, to: String) throws(PlaydateError) {
let result = from.withPlaydateCString { cFrom in
to.withPlaydateCString { cTo in
fileAPI.rename.unsafelyUnwrapped(cFrom, cTo)
fileAPI.pointee.rename.unsafelyUnwrapped(cFrom, cTo)
}
}
if result != 0 { throw lastFileError() }
@@ -123,7 +123,7 @@ extension File {
/// Opens the file at `path`.
public init(path: String, mode: Options) throws(PlaydateError) {
let pointer = path.withPlaydateCString {
fileAPI.open.unsafelyUnwrapped($0, mode.cValue)
fileAPI.pointee.open.unsafelyUnwrapped($0, mode.cValue)
}
guard let pointer else { throw lastFileError() }
self.pointer = pointer
@@ -131,7 +131,7 @@ extension File {
deinit {
if !isClosed {
_ = fileAPI.close.unsafelyUnwrapped(pointer)
_ = fileAPI.pointee.close.unsafelyUnwrapped(pointer)
}
}
@@ -139,13 +139,13 @@ extension File {
public func close() throws(PlaydateError) {
guard !isClosed else { return }
isClosed = true
if fileAPI.close.unsafelyUnwrapped(pointer) != 0 { throw lastFileError() }
if fileAPI.pointee.close.unsafelyUnwrapped(pointer) != 0 { throw lastFileError() }
}
/// Reads up to `buffer.count` bytes into `buffer`. Returns the number
/// of bytes read; 0 indicates end of file.
public func read(into buffer: UnsafeMutableRawBufferPointer) throws(PlaydateError) -> Int {
let result = fileAPI.read.unsafelyUnwrapped(
let result = fileAPI.pointee.read.unsafelyUnwrapped(
pointer, buffer.baseAddress, UInt32(buffer.count))
if result < 0 { throw lastFileError() }
return Int(result)
@@ -155,7 +155,7 @@ extension File {
public func read(length: Int) throws(PlaydateError) -> [UInt8] {
var bytes = [UInt8](repeating: 0, count: length)
let result = bytes.withUnsafeMutableBytes { buffer in
fileAPI.read.unsafelyUnwrapped(pointer, buffer.baseAddress, UInt32(buffer.count))
fileAPI.pointee.read.unsafelyUnwrapped(pointer, buffer.baseAddress, UInt32(buffer.count))
}
if result < 0 { throw lastFileError() }
bytes.removeLast(length - Int(result))
@@ -165,7 +165,7 @@ extension File {
/// Writes the buffer to the file. Returns the number of bytes written.
@discardableResult
public func write(_ buffer: UnsafeRawBufferPointer) throws(PlaydateError) -> Int {
let result = fileAPI.write.unsafelyUnwrapped(
let result = fileAPI.pointee.write.unsafelyUnwrapped(
pointer, buffer.baseAddress, UInt32(buffer.count))
if result < 0 { throw lastFileError() }
return Int(result)
@@ -175,7 +175,7 @@ extension File {
@discardableResult
public func write(_ bytes: [UInt8]) throws(PlaydateError) -> Int {
let result = bytes.withUnsafeBytes { buffer in
fileAPI.write.unsafelyUnwrapped(pointer, buffer.baseAddress, UInt32(buffer.count))
fileAPI.pointee.write.unsafelyUnwrapped(pointer, buffer.baseAddress, UInt32(buffer.count))
}
if result < 0 { throw lastFileError() }
return Int(result)
@@ -190,21 +190,21 @@ extension File {
/// Flushes buffered writes to disk. Returns the bytes written.
@discardableResult
public func flush() throws(PlaydateError) -> Int {
let result = fileAPI.flush.unsafelyUnwrapped(pointer)
let result = fileAPI.pointee.flush.unsafelyUnwrapped(pointer)
if result < 0 { throw lastFileError() }
return Int(result)
}
/// The current read/write offset.
public func tell() throws(PlaydateError) -> Int {
let result = fileAPI.tell.unsafelyUnwrapped(pointer)
let result = fileAPI.pointee.tell.unsafelyUnwrapped(pointer)
if result < 0 { throw lastFileError() }
return Int(result)
}
/// Moves the read/write offset to `offset` relative to `origin`.
public func seek(to offset: Int, from origin: SeekOrigin = .start) throws(PlaydateError) {
if fileAPI.seek.unsafelyUnwrapped(pointer, Int32(offset), origin.rawValue) != 0 {
if fileAPI.pointee.seek.unsafelyUnwrapped(pointer, Int32(offset), origin.rawValue) != 0 {
throw lastFileError()
}
}