diff options
Diffstat (limited to 'netcore/System.Private.CoreLib/shared/System/Convert.Base64.cs')
| -rw-r--r-- | netcore/System.Private.CoreLib/shared/System/Convert.Base64.cs | 218 |
1 files changed, 0 insertions, 218 deletions
diff --git a/netcore/System.Private.CoreLib/shared/System/Convert.Base64.cs b/netcore/System.Private.CoreLib/shared/System/Convert.Base64.cs deleted file mode 100644 index 869d89936ad..00000000000 --- a/netcore/System.Private.CoreLib/shared/System/Convert.Base64.cs +++ /dev/null @@ -1,218 +0,0 @@ -// Licensed to the .NET Foundation under one or more agreements. -// The .NET Foundation licenses this file to you under the MIT license. -// See the LICENSE file in the project root for more information. - -using System.Diagnostics; -using System.Runtime.CompilerServices; -using System.Runtime.InteropServices; -using Internal.Runtime.CompilerServices; - -namespace System -{ - public static partial class Convert - { - /// <summary> - /// Decode the span of UTF-16 encoded text represented as base 64 into binary data. - /// If the input is not a multiple of 4, or contains illegal characters, it will decode as much as it can, to the largest possible multiple of 4. - /// This invariant allows continuation of the parse with a slower, whitespace-tolerant algorithm. - /// - /// <param name="utf16">The input span which contains UTF-16 encoded text in base 64 that needs to be decoded.</param> - /// <param name="bytes">The output span which contains the result of the operation, i.e. the decoded binary data.</param> - /// <param name="consumed">The number of input bytes consumed during the operation. This can be used to slice the input for subsequent calls, if necessary.</param> - /// <param name="written">The number of bytes written into the output span. This can be used to slice the output for subsequent calls, if necessary.</param> - /// </summary> - /// <returns>Returns: - /// - true - The entire input span was successfully parsed. - /// - false - Only a part of the input span was successfully parsed. Failure causes may include embedded or trailing whitespace, - /// other illegal Base64 characters, trailing characters after an encoding pad ('='), an input span whose length is not divisible by 4 - /// or a destination span that's too small. <paramref name="consumed"/> and <paramref name="written"/> are set so that - /// parsing can continue with a slower whitespace-tolerant algorithm. - /// - /// Note: This is a cut down version of the implementation of Base64.DecodeFromUtf8(), modified the accept UTF16 chars and act as a fast-path - /// helper for the Convert routines when the input string contains no whitespace. - /// </returns> - private static bool TryDecodeFromUtf16(ReadOnlySpan<char> utf16, Span<byte> bytes, out int consumed, out int written) - { - ref char srcChars = ref MemoryMarshal.GetReference(utf16); - ref byte destBytes = ref MemoryMarshal.GetReference(bytes); - - int srcLength = utf16.Length & ~0x3; // only decode input up to the closest multiple of 4. - int destLength = bytes.Length; - - int sourceIndex = 0; - int destIndex = 0; - - if (utf16.Length == 0) - goto DoneExit; - - ref sbyte decodingMap = ref MemoryMarshal.GetReference(DecodingMap); - - // Last bytes could have padding characters, so process them separately and treat them as valid. - const int skipLastChunk = 4; - - int maxSrcLength; - if (destLength >= (srcLength >> 2) * 3) - { - maxSrcLength = srcLength - skipLastChunk; - } - else - { - // This should never overflow since destLength here is less than int.MaxValue / 4 * 3 (i.e. 1610612733) - // Therefore, (destLength / 3) * 4 will always be less than 2147483641 - maxSrcLength = (destLength / 3) * 4; - } - - while (sourceIndex < maxSrcLength) - { - int result = Decode(ref Unsafe.Add(ref srcChars, sourceIndex), ref decodingMap); - if (result < 0) - goto InvalidExit; - WriteThreeLowOrderBytes(ref Unsafe.Add(ref destBytes, destIndex), result); - destIndex += 3; - sourceIndex += 4; - } - - if (maxSrcLength != srcLength - skipLastChunk) - goto InvalidExit; - - // If input is less than 4 bytes, srcLength == sourceIndex == 0 - // If input is not a multiple of 4, sourceIndex == srcLength != 0 - if (sourceIndex == srcLength) - { - goto InvalidExit; - } - - int i0 = Unsafe.Add(ref srcChars, srcLength - 4); - int i1 = Unsafe.Add(ref srcChars, srcLength - 3); - int i2 = Unsafe.Add(ref srcChars, srcLength - 2); - int i3 = Unsafe.Add(ref srcChars, srcLength - 1); - if (((i0 | i1 | i2 | i3) & 0xffffff00) != 0) - goto InvalidExit; - - i0 = Unsafe.Add(ref decodingMap, i0); - i1 = Unsafe.Add(ref decodingMap, i1); - - i0 <<= 18; - i1 <<= 12; - - i0 |= i1; - - if (i3 != EncodingPad) - { - i2 = Unsafe.Add(ref decodingMap, i2); - i3 = Unsafe.Add(ref decodingMap, i3); - - i2 <<= 6; - - i0 |= i3; - i0 |= i2; - - if (i0 < 0) - goto InvalidExit; - if (destIndex > destLength - 3) - goto InvalidExit; - WriteThreeLowOrderBytes(ref Unsafe.Add(ref destBytes, destIndex), i0); - destIndex += 3; - } - else if (i2 != EncodingPad) - { - i2 = Unsafe.Add(ref decodingMap, i2); - - i2 <<= 6; - - i0 |= i2; - - if (i0 < 0) - goto InvalidExit; - if (destIndex > destLength - 2) - goto InvalidExit; - Unsafe.Add(ref destBytes, destIndex) = (byte)(i0 >> 16); - Unsafe.Add(ref destBytes, destIndex + 1) = (byte)(i0 >> 8); - destIndex += 2; - } - else - { - if (i0 < 0) - goto InvalidExit; - if (destIndex > destLength - 1) - goto InvalidExit; - Unsafe.Add(ref destBytes, destIndex) = (byte)(i0 >> 16); - destIndex++; - } - - sourceIndex += 4; - - if (srcLength != utf16.Length) - goto InvalidExit; - - DoneExit: - consumed = sourceIndex; - written = destIndex; - return true; - - InvalidExit: - consumed = sourceIndex; - written = destIndex; - Debug.Assert((consumed % 4) == 0); - return false; - } - - [MethodImpl(MethodImplOptions.AggressiveInlining)] - private static int Decode(ref char encodedChars, ref sbyte decodingMap) - { - int i0 = encodedChars; - int i1 = Unsafe.Add(ref encodedChars, 1); - int i2 = Unsafe.Add(ref encodedChars, 2); - int i3 = Unsafe.Add(ref encodedChars, 3); - - if (((i0 | i1 | i2 | i3) & 0xffffff00) != 0) - return -1; // One or more chars falls outside the 00..ff range. This cannot be a valid Base64 character. - - i0 = Unsafe.Add(ref decodingMap, i0); - i1 = Unsafe.Add(ref decodingMap, i1); - i2 = Unsafe.Add(ref decodingMap, i2); - i3 = Unsafe.Add(ref decodingMap, i3); - - i0 <<= 18; - i1 <<= 12; - i2 <<= 6; - - i0 |= i3; - i1 |= i2; - - i0 |= i1; - return i0; - } - - [MethodImpl(MethodImplOptions.AggressiveInlining)] - private static void WriteThreeLowOrderBytes(ref byte destination, int value) - { - destination = (byte)(value >> 16); - Unsafe.Add(ref destination, 1) = (byte)(value >> 8); - Unsafe.Add(ref destination, 2) = (byte)value; - } - - // Pre-computing this table using a custom string(s_characters) and GenerateDecodingMapAndVerify (found in tests) - private static ReadOnlySpan<sbyte> DecodingMap => new sbyte[] // rely on C# compiler optimization to reference static data - { - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, // 62 is placed at index 43 (for +), 63 at index 47 (for /) - 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 52-61 are placed at index 48-57 (for 0-9), 64 at index 61 (for =) - -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, - 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, // 0-25 are placed at index 65-90 (for A-Z) - -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, - 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, // 26-51 are placed at index 97-122 (for a-z) - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // Bytes over 122 ('z') are invalid and cannot be decoded - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // Hence, padding the map with 255, which indicates invalid input - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - }; - - private const byte EncodingPad = (byte)'='; // '=', for padding - } -} |