Fill out test coverage of BinaryParsing

Author: natecook1000

Scripts/format.sh

@@ -18,3 +18,5 @@ echo "Formatting Swift sources in $(pwd)"
 # Run the format / lint commands
 git ls-files -z '*.swift' | xargs -0 swift format format --parallel --in-place
 git ls-files -z '*.swift' | xargs -0 swift format lint --strict --parallel
+
+sed -i '' 's/borrowbuffer/borrow buffer/g' "Sources/BinaryParsing/Parser Types/ParserSpan.swift"

Sources/BinaryParsing/Parser Types/ParserRange.swift

@@ -9,7 +9,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-public struct ParserRange: Hashable {
+public struct ParserRange: Hashable, Sendable {
   @usableFromInline
   internal var range: Range<Int>
 

Sources/BinaryParsing/Parser Types/ParserSource.swift

@@ -122,6 +122,7 @@ extension Data: ParserSpanProvider {
 #endif
 
 extension ParserSpanProvider where Self: RandomAccessCollection<UInt8> {
+  @discardableResult
   @inlinable
   public func withParserSpan<T>(
     _ body: (inout ParserSpan) throws(ThrownParsingError) -> T

Sources/BinaryParsing/Parser Types/ParsingError.swift

@@ -94,6 +94,19 @@ extension ParsingError: CustomStringConvertible {
     }
   }
 }
+
+extension ParsingError.Status: CustomStringConvertible {
+  public var description: String {
+    switch self.rawValue {
+    case .insufficientData:
+      "insufficient data"
+    case .invalidValue:
+      "invalid value"
+    case .userError:
+      "user error"
+    }
+  }
+}
 #endif
 
 #if !$Embedded

Sources/BinaryParsing/Parser Types/Seeking.swift

@@ -97,11 +97,10 @@ extension ParserSpan {
     throws(ParsingError)
   {
     guard let offset = Int(exactly: offset),
-      (0..._bytes.byteCount).contains(offset)
+      (0...endPosition).contains(offset)
     else {
       throw ParsingError(status: .invalidValue, location: startPosition)
     }
-    self._lowerBound = _bytes.byteCount &- offset
-    self._upperBound = _bytes.byteCount
+    self._lowerBound = endPosition &- offset
   }
 }

Sources/BinaryParsing/Parser Types/Slicing.swift

@@ -15,7 +15,7 @@ extension ParserSpan {
   public mutating func sliceSpan(byteCount: some FixedWidthInteger)
     throws(ParsingError) -> ParserSpan
   {
-    guard let byteCount = Int(exactly: byteCount), count >= 0 else {
+    guard let byteCount = Int(exactly: byteCount), byteCount >= 0 else {
       throw ParsingError(status: .invalidValue, location: startPosition)
     }
     guard count >= byteCount else {
@@ -60,18 +60,25 @@ extension ParserSpan {
     try sliceSpan(objectStride: objectStride, objectCount: objectCount)
       .parserRange
   }
+
+  @inlinable
+  @lifetime(&self)
+  public mutating func sliceRemainingRange() -> ParserRange {
+    divide(atOffset: self.count).parserRange
+  }
 }
 
 extension ParserSpan {
   @inlinable
   @lifetime(copy self)
-  @available(macOS 9999, *)
+  @available(macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, *)
   public mutating func sliceUTF8Span(byteCount: some FixedWidthInteger)
     throws(ParsingError) -> UTF8Span
   {
     let rawSpan = try sliceSpan(byteCount: byteCount).bytes
     do {
-      return try UTF8Span(validating: Span<UInt8>(_bytes: rawSpan))
+      let span = Span<UInt8>(_bytes: rawSpan)
+      return try UTF8Span(validating: span)
     } catch {
       throw ParsingError(status: .userError, location: startPosition)
     }

Tests/BinaryParsingTests/ArrayParsingTests.swift

@@ -0,0 +1,244 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Binary Parsing open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+import BinaryParsing
+import Testing
+
+struct ArrayParsingTests {
+  private let testBuffer: [UInt8] = [
+    0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A,
+  ]
+
+  private let emptyBuffer: [UInt8] = []
+
+  @Test
+  func parseRemainingBytes() throws {
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsingRemainingBytes: &span)
+      #expect(parsedArray == testBuffer)
+      #expect(span.count == 0)
+    }
+
+    // Test parsing after consuming part of the buffer
+    try testBuffer.withParserSpan { span in
+      try span.seek(toRelativeOffset: 3)
+      let parsedArray = try Array(parsingRemainingBytes: &span)
+      #expect(parsedArray[...] == testBuffer.dropFirst(3))
+      #expect(span.count == 0)
+    }
+
+    // Test with an empty span
+    try emptyBuffer.withParserSpan { span in
+      let parsedArray = try [UInt8](parsingRemainingBytes: &span)
+      #expect(parsedArray.isEmpty)
+    }
+  }
+
+  @Test
+  func parseByteCount() throws {
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try [UInt8](parsing: &span, byteCount: 5)
+      #expect(parsedArray[...] == testBuffer.prefix(5))
+      #expect(span.count == 5)
+
+      let parsedArray2 = try [UInt8](parsing: &span, byteCount: 3)
+      #expect(parsedArray2[...] == testBuffer.dropFirst(5).prefix(3))
+      #expect(span.count == 2)
+    }
+
+    // 'byteCount' == 0
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try [UInt8](parsing: &span, byteCount: 0)
+      #expect(parsedArray.isEmpty)
+      #expect(span.count == testBuffer.count)
+    }
+
+    // 'byteCount' greater than available bytes
+    try testBuffer.withParserSpan { span in
+      #expect(throws: ParsingError.self) {
+        _ = try [UInt8](parsing: &span, byteCount: testBuffer.count + 1)
+      }
+      #expect(span.count == testBuffer.count)
+    }
+  }
+
+  @Test
+  func parseArrayOfFixedSize() throws {
+    // Arrays of fixed-size integers
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsing: &span, count: 5) { input in
+        try UInt8(parsing: &input)
+      }
+      #expect(parsedArray[...] == testBuffer.prefix(5))
+      #expect(span.count == 5)
+
+      // Parse two UInt16 values
+      let parsedArray2 = try Array(parsing: &span, count: 2) { input in
+        try UInt16(parsingBigEndian: &input)
+      }
+      #expect(parsedArray2 == [0x0607, 0x0809])
+      #expect(span.count == 1)
+
+      // Fail to parse one UInt16
+      #expect(throws: ParsingError.self) {
+        _ = try Array(parsing: &span, count: 1) { input in
+          try UInt16(parsingBigEndian: &input)
+        }
+      }
+
+      let lastByte = try Array(
+        parsing: &span,
+        count: 1,
+        parser: UInt8.init(parsing:))
+      #expect(lastByte == [0x0A])
+      #expect(span.count == 0)
+    }
+
+    // Parsing count = 0 always succeeds
+    try testBuffer.withParserSpan { span in
+      let parsedArray1 = try Array(parsing: &span, count: 0) { input in
+        try UInt64(parsingBigEndian: &input)
+      }
+      #expect(parsedArray1.isEmpty)
+      #expect(span.count == testBuffer.count)
+
+      try span.seek(toOffsetFromEnd: 0)
+      let parsedArray2 = try Array(parsing: &span, count: 0) { input in
+        try UInt64(parsingBigEndian: &input)
+      }
+      #expect(parsedArray2.isEmpty)
+      #expect(span.count == 0)
+    }
+
+    // Non-'Int' count that would overflow
+    _ = try testBuffer.withParserSpan { span in
+      #expect(throws: ParsingError.self) {
+        _ = try [UInt8](parsing: &span, count: UInt.max) { input in
+          try UInt8(parsing: &input)
+        }
+      }
+    }
+  }
+
+  @Test
+  func parseArrayOfCustomTypes() throws {
+    // Define a custom struct to test with
+    struct CustomType {
+      var value: UInt8
+      var doubled: UInt8
+
+      init(parsing input: inout ParserSpan) throws {
+        self.value = try UInt8(parsing: &input)
+        guard let d = self.value *? 2 else {
+          throw TestError("Doubled value too large for UInt8")
+        }
+        self.doubled = d
+      }
+    }
+
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsing: &span, count: 5) { input in
+        try CustomType(parsing: &input)
+      }
+
+      #expect(parsedArray.map(\.value) == [0x01, 0x02, 0x03, 0x04, 0x05])
+      #expect(parsedArray.map(\.doubled) == [0x02, 0x04, 0x06, 0x08, 0x0A])
+      #expect(span.count == 5)
+    }
+
+    _ = try [0x0f, 0xf0].withParserSpan { span in
+      #expect(throws: TestError.self) {
+        try Array(parsingAll: &span, parser: CustomType.init(parsing:))
+      }
+    }
+  }
+
+  @Test
+  func parseAllAvailableElements() throws {
+    // Parse as UInt8
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsingAll: &span) { input in
+        try UInt8(parsing: &input)
+      }
+      #expect(parsedArray == testBuffer)
+      #expect(span.count == 0)
+    }
+
+    // Parse as UInt16
+    try testBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsingAll: &span) { input in
+        try UInt16(parsingBigEndian: &input)
+      }
+      #expect(parsedArray == [0x0102, 0x0304, 0x0506, 0x0708, 0x090A])
+      #expect(span.count == 0)
+    }
+
+    // Parse as UInt16 with recovery
+    let oddBuffer: [UInt8] = [0x01, 0x02, 0x03, 0x04, 0x05]
+    try oddBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsingAll: &span) { input in
+        do {
+          return try UInt16(parsingBigEndian: &input)
+        } catch {
+          if input.count == 1 {
+            return try UInt16(parsing: &input, storedAs: UInt8.self)
+          }
+          throw error
+        }
+      }
+
+      // Two complete 'UInt16' values plus one 'UInt16' from the last byte
+      #expect(parsedArray == [0x0102, 0x0304, 0x0005])
+      #expect(span.count == 0)
+    }
+
+    // Test with empty buffer
+    try emptyBuffer.withParserSpan { span in
+      let parsedArray = try Array(parsingAll: &span) { input in
+        try UInt8(parsing: &input)
+      }
+      #expect(parsedArray.isEmpty)
+      #expect(span.count == 0)
+    }
+  }
+
+  @Test
+  func parseArrayWithErrorHandling() throws {
+    struct ValidatedUInt8 {
+      var value: UInt8
+
+      init(parsing input: inout ParserSpan) throws {
+        self.value = try UInt8(parsing: &input)
+        if value > 5 {
+          throw TestError("Value \(value) exceeds maximum allowed value of 5")
+        }
+      }
+    }
+
+    try testBuffer.withParserSpan { span in
+      // This should fail because values in the buffer exceed 5
+      #expect(throws: TestError.self) {
+        _ = try Array(parsing: &span, count: testBuffer.count) { input in
+          try ValidatedUInt8(parsing: &input)
+        }
+      }
+      // Even though the parsing failed, it should have consumed some elements
+      #expect(span.count < testBuffer.count)
+
+      // Reset and try just parsing the valid values
+      try span.seek(toAbsoluteOffset: 0)
+      let parsedArray = try Array(parsing: &span, count: 5) { input in
+        try ValidatedUInt8(parsing: &input)
+      }
+      #expect(parsedArray.map(\.value) == [0x01, 0x02, 0x03, 0x04, 0x05])
+    }
+  }
+}