initial commit, 4.5 stable

thirdparty/libktx/external/dfdutils/queries.c

@@ -0,0 +1,215 @@
+/* -*- tab-width: 4; -*- */
+/* vi: set sw=2 ts=4 expandtab: */
+
+/* Copyright 2019-2020 The Khronos Group Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @~English
+ * @brief Utilities for querying info from a data format descriptor.
+ * @author Mark Callow
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <KHR/khr_df.h>
+#include "dfd.h"
+
+/**
+ * @~English
+ * @brief Get the number and size of the image components from a DFD.
+ *
+ * This simplified function is for use only with the DFDs for unpacked
+ * formats which means all components have the same size.
+ *
+ * @param DFD Pointer to a Data Format Descriptor to interpret,
+              described as 32-bit words in native endianness.
+              Note that this is the whole descriptor, not just
+              the basic descriptor block.
+ * @param numComponents pointer to a 32-bit word in which the number of
+                        components will be written.
+ * @param componentByteLength pointer to a 32-bit word in which the size of
+                              a component in bytes will be written.
+ */
+void
+getDFDComponentInfoUnpacked(const uint32_t* DFD, uint32_t* numComponents,
+                            uint32_t* componentByteLength)
+{
+    const uint32_t *BDFDB = DFD+1;
+    uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB);
+    uint32_t sampleNumber;
+    uint32_t currentChannel = ~0U; /* Don't start matched. */
+
+    /* This is specifically for unpacked formats which means the size of */
+    /* each component is the same. */
+    *numComponents = 0;
+    for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) {
+        uint32_t sampleByteLength = (KHR_DFDSVAL(BDFDB, sampleNumber, BITLENGTH) + 1) >> 3U;
+        uint32_t sampleChannel = KHR_DFDSVAL(BDFDB, sampleNumber, CHANNELID);
+
+        if (sampleChannel == currentChannel) {
+            /* Continuation of the same channel. */
+            /* Accumulate the byte length. */
+            *componentByteLength += sampleByteLength;
+        } else {
+            /* Everything is new. Hopefully. */
+            currentChannel = sampleChannel;
+            (*numComponents)++;
+            *componentByteLength = sampleByteLength;
+        }
+    }
+}
+
+/**
+ * @~English
+ * @brief Return the number of "components" in the data.
+ *
+ * Calculates the number of uniques samples in the DFD by combining
+ * multiple samples for the same channel. For uncompressed colorModels
+ * this is the same as the number of components in the image data. For
+ * block-compressed color models this is the number of samples in
+ * the color model, typically 1 and in a few cases 2.
+ *
+ * @param DFD Pointer to a Data Format Descriptor for which,
+ *            described as 32-bit words in native endianness.
+ *            Note that this is the whole descriptor, not just
+ *            the basic descriptor block.
+ */
+uint32_t getDFDNumComponents(const uint32_t* DFD)
+{
+    const uint32_t *BDFDB = DFD+1;
+    uint32_t currentChannel = ~0U; /* Don't start matched. */
+    uint32_t numComponents = 0;
+    uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB);
+    uint32_t sampleNumber;
+
+    for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) {
+        uint32_t sampleChannel = KHR_DFDSVAL(BDFDB, sampleNumber, CHANNELID);
+        if (sampleChannel != currentChannel) {
+            numComponents++;
+            currentChannel = sampleChannel;
+        }
+    }
+    return numComponents;
+}
+
+/**
+ * @~English
+ * @brief Reconstruct the value of bytesPlane0 from sample info.
+ *
+ * @deprecated Use reconstructDFDBytesPlanesFromSamples. This does not handle
+ *             the possible second plane of the ETC1S model.
+ *
+ * Reconstruct the value for data that has been variable-rate compressed
+ * and and whose bytesPlane0 value has been set to 0.  For DFDs that
+ * are valid for KTX files. Little-endian data only and no multi-plane models
+ * except ETC1S.
+ *
+ * @param DFD Pointer to the Data Format Descriptor for which to provide
+ *            the value described as 32-bit words in native endianness.
+ *            Note that this is the whole descriptor, not just
+ *            the basic descriptor block.
+ * @return The number of bytes a pixel occupies in bytesPlane0.
+ */
+uint32_t
+reconstructDFDBytesPlane0FromSamples(const uint32_t* DFD)
+{
+    const uint32_t *BDFDB = DFD+1;
+    uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB);
+    uint32_t sampleNumber;
+
+    uint32_t bitsPlane0 = 0;
+    int32_t largestOffset = 0;
+    uint32_t sampleNumberWithLargestOffset = 0;
+
+    // Special case these depth{,-stencil} formats. The unused bits are
+    // in the MSBs so have no visibility in the DFD therefore the max offset
+    // algorithm below returns a value that is too small.
+    if (KHR_DFDSVAL(BDFDB, 0, CHANNELID) == KHR_DF_CHANNEL_COMMON_DEPTH) {
+        if (numSamples == 1) {
+            if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 24) {
+                // X8_D24_UNORM_PACK32,
+                return 4;
+            }
+        } else if (numSamples == 2) {
+            if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 16) {
+                // D16_UNORM_S8_UINT
+                return 4;
+            }
+            if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 32
+                && KHR_DFDSVAL(BDFDB, 1, CHANNELID) == KHR_DF_CHANNEL_COMMON_STENCIL) {
+                // D32_SFLOAT_S8_UINT
+                return 8;
+            }
+        }
+    }
+    if (KHR_DFDVAL(BDFDB, MODEL) == KHR_DF_MODEL_ETC1S) {
+        // Size of the first plane.
+        return 8;
+    }
+    for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) {
+        int32_t sampleBitOffset = KHR_DFDSVAL(BDFDB, sampleNumber, BITOFFSET);
+        if (sampleBitOffset > largestOffset) {
+            largestOffset = sampleBitOffset;
+            sampleNumberWithLargestOffset = sampleNumber;
+        }
+    }
+
+    /* The sample bitLength field stores the bit length - 1. */
+    uint32_t sampleBitLength = KHR_DFDSVAL(BDFDB, sampleNumberWithLargestOffset, BITLENGTH) + 1;
+    bitsPlane0 = largestOffset + sampleBitLength;
+    return bitsPlane0 >> 3U;
+}
+
+/**
+ * @~English
+ * @brief Reconstruct the values of bytesPlane[01] from sample info.
+ *
+ * Reconstruct the values for data that has been variable-rate compressed
+ * and whose bytesPlane[01] values have been set to 0 and update the
+ * fields of the target DFD. For DFDs that are valid for KTX files.
+ * Little-endian data only and no multi-plane models except ETC1S hence
+ * only looking at bytesPlane0 abd bytesPlane1.
+ *
+ * @param DFD Pointer to a Data Format Descriptor for which,
+ *            described as 32-bit words in native endianness.
+ *            Note that this is the whole descriptor, not just
+ *            the basic descriptor block.
+ */
+
+void
+reconstructDFDBytesPlanesFromSamples(uint32_t* DFD)
+{
+    uint32_t *BDFDB = DFD+1;
+
+    KHR_DFDSETVAL(BDFDB, BYTESPLANE0, reconstructDFDBytesPlane0FromSamples(DFD));
+    if (KHR_DFDVAL(BDFDB, MODEL) == KHR_DF_MODEL_ETC1S) {
+        if (KHR_DFDSAMPLECOUNT(BDFDB) == 2)
+            KHR_DFDSETVAL(BDFDB, BYTESPLANE1, 8);
+    }
+}
+
+/**
+ * @~English
+ * @brief Reconstruct the value of bytesPlane0 from sample info.
+ *
+ * @see reconstructDFDBytesPlane0FromSamples for details.
+ * @deprecated For backward comparibility only. Use
+ *             reconstructDFDBytesPlanesFromSamples.
+ *
+ * @param DFD Pointer to the Data Format Descriptor for which to provide
+ *            the value described as 32-bit words in native endianness.
+ *            Note that this is the whole descriptor, not just
+ *            the basic descriptor block.
+ * @param bytesPlane0  pointer to a 32-bit word in which the recreated
+ *                    value of bytesPlane0 will be written.
+ */
+void
+recreateBytesPlane0FromSampleInfo(const uint32_t* DFD, uint32_t* bytesPlane0)
+{
+    *bytesPlane0 = reconstructDFDBytesPlane0FromSamples(DFD);
+}