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Fix SEGV on macOS
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@Bond-009
Bond-009 committed Jul 6, 2023
1 parent 5275ad3 commit faa1264
Showing 1 changed file with 88 additions and 82 deletions.
170 changes: 88 additions & 82 deletions src/BlurHashSharp/CoreBlurHashEncoder.cs
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Original file line number Diff line number Diff line change
@@ -1,9 +1,6 @@
using System;
using System.Runtime.CompilerServices;
using System.Buffers;
using System.Diagnostics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.Arm;
using System.Runtime.Intrinsics.X86;

namespace BlurHashSharp
{
Expand Down Expand Up @@ -105,7 +102,6 @@ static int ThrowPixelFormatArgumentException()

int totalComponents = xComponents * yComponents;
int factorsLen = totalComponents * 3;
float[] factors = new float[factorsLen];

int bytesPerPixel = pixelFormat switch
{
Expand All @@ -116,102 +112,112 @@ static int ThrowPixelFormatArgumentException()
_ => ThrowPixelFormatArgumentException()
};

Span<float> cosYLookup = stackalloc float[height];
Span<float> cosXLookup = stackalloc float[width];
ReadOnlySpan<float> sRGBToLinearLookup = _sRGBToLinearLookup;

int totalPixels = width * height;
float dcScale = 1f / totalPixels;
float acScale = 2f / totalPixels;

for (int yC = 0; yC < yComponents; yC++)
float[] rented = ArrayPool<float>.Shared.Rent(factorsLen + height + width);
try
{
PrecomputeCosines(cosYLookup, MathF.PI * yC / height);
Memory<float> factors = rented.AsMemory(0, factorsLen);
Span<float> factorsSpan = factors.Span;
Span<float> cosYLookup = rented.AsSpan(factorsLen, height);
Span<float> cosXLookup = rented.AsSpan(factorsLen + height, width);
ReadOnlySpan<float> sRGBToLinearLookup = _sRGBToLinearLookup;

for (int xC = 0; xC < xComponents; xC++)
{
PrecomputeCosines(cosXLookup, MathF.PI * xC / width);
int totalPixels = width * height;
float dcScale = 1f / totalPixels;
float acScale = 2f / totalPixels;

float c1 = 0;
float c2 = 0;
float c3 = 0;
for (int yC = 0; yC < yComponents; yC++)
{
PrecomputeCosines(cosYLookup, MathF.PI * yC / height);

for (int y = 0; y < height; y++)
for (int xC = 0; xC < xComponents; xC++)
{
float yBasis = cosYLookup[y];
int offset = y * bytesPerRow;
for (int x = 0; x < width; x++)
{
float basis = cosXLookup[x] * yBasis;
c1 += basis * sRGBToLinearLookup[pixels[offset]];
c2 += basis * sRGBToLinearLookup[pixels[offset + 1]];
c3 += basis * sRGBToLinearLookup[pixels[offset + 2]];
PrecomputeCosines(cosXLookup, MathF.PI * xC / width);

float c1 = 0;
float c2 = 0;
float c3 = 0;

offset += bytesPerPixel;
for (int y = 0; y < height; y++)
{
float yBasis = cosYLookup[y];
int offset = y * bytesPerRow;
for (int x = 0; x < width; x++)
{
float basis = cosXLookup[x] * yBasis;
c1 += basis * sRGBToLinearLookup[pixels[offset]];
c2 += basis * sRGBToLinearLookup[pixels[offset + 1]];
c3 += basis * sRGBToLinearLookup[pixels[offset + 2]];

offset += bytesPerPixel;
}
}
}

int factorOffset = ((yC * xComponents) + xC) * 3;
float scale = (xC == 0 && yC == 0) ? dcScale : acScale;
factors[factorOffset] = c1 * scale;
factors[factorOffset + 1] = c2 * scale;
factors[factorOffset + 2] = c3 * scale;
int factorOffset = ((yC * xComponents) + xC) * 3;
float scale = (xC == 0 && yC == 0) ? dcScale : acScale;
factorsSpan[factorOffset] = c1 * scale;
factorsSpan[factorOffset + 1] = c2 * scale;
factorsSpan[factorOffset + 2] = c3 * scale;
}
}
}

int acCount = totalComponents - 1;
int hashLen = 1 + 1 + 4 + (acCount * 2);

return string.Create(
hashLen,
(pixelFormat, factors, acCount),
(hash, state) =>
{
ReadOnlySpan<float> dc = factors.AsSpan(0, 3);
ReadOnlySpan<float> ac = factors.AsSpan(3);
int acLen = ac.Length;
int acCount = totalComponents - 1;
int hashLen = 1 + 1 + 4 + (acCount * 2);

int hashPos = EncodeBase83(xComponents - 1 + ((yComponents - 1) * 9), 1, hash);
float maximumValue;
if (state.acCount > 0)
return string.Create(
hashLen,
(pixelFormat, acCount),
(hash, state) =>
{
float actualMaximumValue = ac.AbsMax();
ReadOnlySpan<float> dc = factors.Slice(0, 3).Span;
ReadOnlySpan<float> ac = factors.Slice(3).Span;
int acLen = ac.Length;
int quantisedMaximumValue = Math.Clamp((int)((actualMaximumValue * 166f) - 0.5f), 0, 82);
maximumValue = (quantisedMaximumValue + 1) / 166f;
hashPos += EncodeBase83(quantisedMaximumValue, 1, hash.Slice(hashPos));
}
else
{
maximumValue = 1;
hashPos += EncodeBase83(0, 1, hash.Slice(hashPos));
}
int hashPos = EncodeBase83(xComponents - 1 + ((yComponents - 1) * 9), 1, hash);
float maximumValue;
if (state.acCount > 0)
{
float actualMaximumValue = ac.AbsMax();
switch (state.pixelFormat)
{
case PixelFormat.BGR888:
case PixelFormat.BGR888x:
hashPos += EncodeBase83(EncodeDC(dc[2], dc[1], dc[0]), 4, hash.Slice(hashPos));
int quantisedMaximumValue = Math.Clamp((int)((actualMaximumValue * 166f) - 0.5f), 0, 82);
maximumValue = (quantisedMaximumValue + 1) / 166f;
hashPos += EncodeBase83(quantisedMaximumValue, 1, hash.Slice(hashPos));
}
else
{
maximumValue = 1;
hashPos += EncodeBase83(0, 1, hash.Slice(hashPos));
}
for (int i = 0; i < acLen; i += 3)
{
hashPos += EncodeBase83(EncodeAC(ac[i + 2], ac[i + 1], ac[i], maximumValue), 2, hash.Slice(hashPos));
}
switch (state.pixelFormat)
{
case PixelFormat.BGR888:
case PixelFormat.BGR888x:
hashPos += EncodeBase83(EncodeDC(dc[2], dc[1], dc[0]), 4, hash.Slice(hashPos));
break;
for (int i = 0; i < acLen; i += 3)
{
hashPos += EncodeBase83(EncodeAC(ac[i + 2], ac[i + 1], ac[i], maximumValue), 2, hash.Slice(hashPos));
}
case PixelFormat.RGB888:
case PixelFormat.RGB888x:
hashPos += EncodeBase83(EncodeDC(dc[0], dc[1], dc[2]), 4, hash.Slice(hashPos));
break;
for (int i = 0; i < acLen; i += 3)
{
hashPos += EncodeBase83(EncodeAC(ac[i], ac[i + 1], ac[i + 2], maximumValue), 2, hash.Slice(hashPos));
}
case PixelFormat.RGB888:
case PixelFormat.RGB888x:
hashPos += EncodeBase83(EncodeDC(dc[0], dc[1], dc[2]), 4, hash.Slice(hashPos));
break;
}
});
for (int i = 0; i < acLen; i += 3)
{
hashPos += EncodeBase83(EncodeAC(ac[i], ac[i + 1], ac[i + 2], maximumValue), 2, hash.Slice(hashPos));
}
break;
}
});
}
finally
{
ArrayPool<float>.Shared.Return(rented);
}
}

internal static void PrecomputeCosines(Span<float> table, float offset)
Expand Down

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