diff --git a/libs/ultrahdr/icc.cpp b/libs/ultrahdr/icc.cpp
new file mode 100644
index 0000000..c807705
--- /dev/null
+++ b/libs/ultrahdr/icc.cpp
@@ -0,0 +1,585 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <ultrahdr/icc.h>
+#include <ultrahdr/gainmapmath.h>
+#include <vector>
+#include <utils/Log.h>
+
+#ifndef FLT_MAX
+#define FLT_MAX 0x1.fffffep127f
+#endif
+
+namespace android::ultrahdr {
+static void Matrix3x3_apply(const Matrix3x3* m, float* x) {
+    float y0 = x[0] * m->vals[0][0] + x[1] * m->vals[0][1] + x[2] * m->vals[0][2];
+    float y1 = x[0] * m->vals[1][0] + x[1] * m->vals[1][1] + x[2] * m->vals[1][2];
+    float y2 = x[0] * m->vals[2][0] + x[1] * m->vals[2][1] + x[2] * m->vals[2][2];
+    x[0] = y0;
+    x[1] = y1;
+    x[2] = y2;
+}
+
+bool Matrix3x3_invert(const Matrix3x3* src, Matrix3x3* dst) {
+    double a00 = src->vals[0][0],
+           a01 = src->vals[1][0],
+           a02 = src->vals[2][0],
+           a10 = src->vals[0][1],
+           a11 = src->vals[1][1],
+           a12 = src->vals[2][1],
+           a20 = src->vals[0][2],
+           a21 = src->vals[1][2],
+           a22 = src->vals[2][2];
+
+    double b0 = a00*a11 - a01*a10,
+           b1 = a00*a12 - a02*a10,
+           b2 = a01*a12 - a02*a11,
+           b3 = a20,
+           b4 = a21,
+           b5 = a22;
+
+    double determinant = b0*b5
+                       - b1*b4
+                       + b2*b3;
+
+    if (determinant == 0) {
+        return false;
+    }
+
+    double invdet = 1.0 / determinant;
+    if (invdet > +FLT_MAX || invdet < -FLT_MAX || !isfinitef_((float)invdet)) {
+        return false;
+    }
+
+    b0 *= invdet;
+    b1 *= invdet;
+    b2 *= invdet;
+    b3 *= invdet;
+    b4 *= invdet;
+    b5 *= invdet;
+
+    dst->vals[0][0] = (float)( a11*b5 - a12*b4 );
+    dst->vals[1][0] = (float)( a02*b4 - a01*b5 );
+    dst->vals[2][0] = (float)(        +     b2 );
+    dst->vals[0][1] = (float)( a12*b3 - a10*b5 );
+    dst->vals[1][1] = (float)( a00*b5 - a02*b3 );
+    dst->vals[2][1] = (float)(        -     b1 );
+    dst->vals[0][2] = (float)( a10*b4 - a11*b3 );
+    dst->vals[1][2] = (float)( a01*b3 - a00*b4 );
+    dst->vals[2][2] = (float)(        +     b0 );
+
+    for (int r = 0; r < 3; ++r)
+    for (int c = 0; c < 3; ++c) {
+        if (!isfinitef_(dst->vals[r][c])) {
+            return false;
+        }
+    }
+    return true;
+}
+
+static Matrix3x3 Matrix3x3_concat(const Matrix3x3* A, const Matrix3x3* B) {
+    Matrix3x3 m = { { { 0,0,0 },{ 0,0,0 },{ 0,0,0 } } };
+    for (int r = 0; r < 3; r++)
+        for (int c = 0; c < 3; c++) {
+            m.vals[r][c] = A->vals[r][0] * B->vals[0][c]
+                         + A->vals[r][1] * B->vals[1][c]
+                         + A->vals[r][2] * B->vals[2][c];
+        }
+    return m;
+}
+
+static void float_XYZD50_to_grid16_lab(const float* xyz_float, uint8_t* grid16_lab) {
+    float v[3] = {
+            xyz_float[0] / kD50_x,
+            xyz_float[1] / kD50_y,
+            xyz_float[2] / kD50_z,
+    };
+    for (size_t i = 0; i < 3; ++i) {
+        v[i] = v[i] > 0.008856f ? cbrtf(v[i]) : v[i] * 7.787f + (16 / 116.0f);
+    }
+    const float L = v[1] * 116.0f - 16.0f;
+    const float a = (v[0] - v[1]) * 500.0f;
+    const float b = (v[1] - v[2]) * 200.0f;
+    const float Lab_unorm[3] = {
+            L * (1 / 100.f),
+            (a + 128.0f) * (1 / 255.0f),
+            (b + 128.0f) * (1 / 255.0f),
+    };
+    // This will encode L=1 as 0xFFFF. This matches how skcms will interpret the
+    // table, but the spec appears to indicate that the value should be 0xFF00.
+    // https://crbug.com/skia/13807
+    for (size_t i = 0; i < 3; ++i) {
+        reinterpret_cast<uint16_t*>(grid16_lab)[i] =
+                Endian_SwapBE16(float_round_to_unorm16(Lab_unorm[i]));
+    }
+}
+
+std::string IccHelper::get_desc_string(const ultrahdr_transfer_function tf,
+                                       const ultrahdr_color_gamut gamut) {
+    std::string result;
+    switch (gamut) {
+        case ULTRAHDR_COLORGAMUT_BT709:
+            result += "sRGB";
+            break;
+        case ULTRAHDR_COLORGAMUT_P3:
+            result += "Display P3";
+            break;
+        case ULTRAHDR_COLORGAMUT_BT2100:
+            result += "Rec2020";
+            break;
+        default:
+            result += "Unknown";
+            break;
+    }
+    result += " Gamut with ";
+    switch (tf) {
+        case ULTRAHDR_TF_SRGB:
+            result += "sRGB";
+            break;
+        case ULTRAHDR_TF_LINEAR:
+            result += "Linear";
+            break;
+        case ULTRAHDR_TF_PQ:
+            result += "PQ";
+            break;
+        case ULTRAHDR_TF_HLG:
+            result += "HLG";
+            break;
+        default:
+            result += "Unknown";
+            break;
+    }
+    result += " Transfer";
+    return result;
+}
+
+sp<DataStruct> IccHelper::write_text_tag(const char* text) {
+    uint32_t text_length = strlen(text);
+    uint32_t header[] = {
+            Endian_SwapBE32(kTAG_TextType),                         // Type signature
+            0,                                                      // Reserved
+            Endian_SwapBE32(1),                                     // Number of records
+            Endian_SwapBE32(12),                                    // Record size (must be 12)
+            Endian_SwapBE32(SetFourByteTag('e', 'n', 'U', 'S')),    // English USA
+            Endian_SwapBE32(2 * text_length),                       // Length of string in bytes
+            Endian_SwapBE32(28),                                    // Offset of string
+    };
+
+    uint32_t total_length = text_length * 2 + sizeof(header);
+    total_length = (((total_length + 2) >> 2) << 2);  // 4 aligned
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+
+    if (!dataStruct->write(header, sizeof(header))) {
+        ALOGE("write_text_tag(): error in writing data");
+        return dataStruct;
+    }
+
+    for (size_t i = 0; i < text_length; i++) {
+        // Convert ASCII to big-endian UTF-16.
+        dataStruct->write8(0);
+        dataStruct->write8(text[i]);
+    }
+
+    return dataStruct;
+}
+
+sp<DataStruct> IccHelper::write_xyz_tag(float x, float y, float z) {
+    uint32_t data[] = {
+            Endian_SwapBE32(kXYZ_PCSSpace),
+            0,
+            static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(x))),
+            static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(y))),
+            static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(z))),
+    };
+    sp<DataStruct> dataStruct = new DataStruct(sizeof(data));
+    dataStruct->write(&data, sizeof(data));
+    return dataStruct;
+}
+
+sp<DataStruct> IccHelper::write_trc_tag(const int table_entries, const void* table_16) {
+    int total_length = 4 + 4 + 4 + table_entries * 2;
+    total_length = (((total_length + 2) >> 2) << 2);  // 4 aligned
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+    dataStruct->write32(Endian_SwapBE32(kTAG_CurveType));     // Type
+    dataStruct->write32(0);                                     // Reserved
+    dataStruct->write32(Endian_SwapBE32(table_entries));  // Value count
+    for (size_t i = 0; i < table_entries; ++i) {
+        uint16_t value = reinterpret_cast<const uint16_t*>(table_16)[i];
+        dataStruct->write16(value);
+    }
+    return dataStruct;
+}
+
+sp<DataStruct> IccHelper::write_trc_tag_for_linear() {
+    int total_length = 16;
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+    dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType));  // Type
+    dataStruct->write32(0);                                      // Reserved
+    dataStruct->write32(Endian_SwapBE16(kExponential_ParaCurveType));
+    dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(1.0)));
+
+    return dataStruct;
+}
+
+float IccHelper::compute_tone_map_gain(const ultrahdr_transfer_function tf, float L) {
+    if (L <= 0.f) {
+        return 1.f;
+    }
+    if (tf == ULTRAHDR_TF_PQ) {
+        // The PQ transfer function will map to the range [0, 1]. Linearly scale
+        // it up to the range [0, 10,000/203]. We will then tone map that back
+        // down to [0, 1].
+        constexpr float kInputMaxLuminance = 10000 / 203.f;
+        constexpr float kOutputMaxLuminance = 1.0;
+        L *= kInputMaxLuminance;
+
+        // Compute the tone map gain which will tone map from 10,000/203 to 1.0.
+        constexpr float kToneMapA = kOutputMaxLuminance / (kInputMaxLuminance * kInputMaxLuminance);
+        constexpr float kToneMapB = 1.f / kOutputMaxLuminance;
+        return kInputMaxLuminance * (1.f + kToneMapA * L) / (1.f + kToneMapB * L);
+    }
+    if (tf == ULTRAHDR_TF_HLG) {
+        // Let Lw be the brightness of the display in nits.
+        constexpr float Lw = 203.f;
+        const float gamma = 1.2f + 0.42f * std::log(Lw / 1000.f) / std::log(10.f);
+        return std::pow(L, gamma - 1.f);
+    }
+    return 1.f;
+}
+
+sp<DataStruct> IccHelper::write_cicp_tag(uint32_t color_primaries,
+                                         uint32_t transfer_characteristics) {
+    int total_length = 12;  // 4 + 4 + 1 + 1 + 1 + 1
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+    dataStruct->write32(Endian_SwapBE32(kTAG_cicp));    // Type signature
+    dataStruct->write32(0);                             // Reserved
+    dataStruct->write8(color_primaries);                // Color primaries
+    dataStruct->write8(transfer_characteristics);       // Transfer characteristics
+    dataStruct->write8(0);                              // RGB matrix
+    dataStruct->write8(1);                              // Full range
+    return dataStruct;
+}
+
+void IccHelper::compute_lut_entry(const Matrix3x3& src_to_XYZD50, float rgb[3]) {
+    // Compute the matrices to convert from source to Rec2020, and from Rec2020 to XYZD50.
+    Matrix3x3 src_to_rec2020;
+    const Matrix3x3 rec2020_to_XYZD50 = kRec2020;
+    {
+        Matrix3x3 XYZD50_to_rec2020;
+        Matrix3x3_invert(&rec2020_to_XYZD50, &XYZD50_to_rec2020);
+        src_to_rec2020 = Matrix3x3_concat(&XYZD50_to_rec2020, &src_to_XYZD50);
+    }
+
+    // Convert the source signal to linear.
+    for (size_t i = 0; i < kNumChannels; ++i) {
+        rgb[i] = pqOetf(rgb[i]);
+    }
+
+    // Convert source gamut to Rec2020.
+    Matrix3x3_apply(&src_to_rec2020, rgb);
+
+    // Compute the luminance of the signal.
+    float L = bt2100Luminance({{{rgb[0], rgb[1], rgb[2]}}});
+
+    // Compute the tone map gain based on the luminance.
+    float tone_map_gain = compute_tone_map_gain(ULTRAHDR_TF_PQ, L);
+
+    // Apply the tone map gain.
+    for (size_t i = 0; i < kNumChannels; ++i) {
+        rgb[i] *= tone_map_gain;
+    }
+
+    // Convert from Rec2020-linear to XYZD50.
+    Matrix3x3_apply(&rec2020_to_XYZD50, rgb);
+}
+
+sp<DataStruct> IccHelper::write_clut(const uint8_t* grid_points, const uint8_t* grid_16) {
+    uint32_t value_count = kNumChannels;
+    for (uint32_t i = 0; i < kNumChannels; ++i) {
+        value_count *= grid_points[i];
+    }
+
+    int total_length = 20 + 2 * value_count;
+    total_length = (((total_length + 2) >> 2) << 2);  // 4 aligned
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+
+    for (size_t i = 0; i < 16; ++i) {
+        dataStruct->write8(i < kNumChannels ? grid_points[i] : 0);  // Grid size
+    }
+    dataStruct->write8(2);  // Grid byte width (always 16-bit)
+    dataStruct->write8(0);  // Reserved
+    dataStruct->write8(0);  // Reserved
+    dataStruct->write8(0);  // Reserved
+
+    for (uint32_t i = 0; i < value_count; ++i) {
+        uint16_t value = reinterpret_cast<const uint16_t*>(grid_16)[i];
+        dataStruct->write16(value);
+    }
+
+    return dataStruct;
+}
+
+sp<DataStruct> IccHelper::write_mAB_or_mBA_tag(uint32_t type,
+                                               bool has_a_curves,
+                                               const uint8_t* grid_points,
+                                               const uint8_t* grid_16) {
+    const size_t b_curves_offset = 32;
+    sp<DataStruct> b_curves_data[kNumChannels];
+    sp<DataStruct> a_curves_data[kNumChannels];
+    size_t clut_offset = 0;
+    sp<DataStruct> clut;
+    size_t a_curves_offset = 0;
+
+    // The "B" curve is required.
+    for (size_t i = 0; i < kNumChannels; ++i) {
+        b_curves_data[i] = write_trc_tag_for_linear();
+    }
+
+    // The "A" curve and CLUT are optional.
+    if (has_a_curves) {
+        clut_offset = b_curves_offset;
+        for (size_t i = 0; i < kNumChannels; ++i) {
+            clut_offset += b_curves_data[i]->getLength();
+        }
+        clut = write_clut(grid_points, grid_16);
+
+        a_curves_offset = clut_offset + clut->getLength();
+        for (size_t i = 0; i < kNumChannels; ++i) {
+            a_curves_data[i] = write_trc_tag_for_linear();
+        }
+    }
+
+    int total_length = b_curves_offset;
+    for (size_t i = 0; i < kNumChannels; ++i) {
+        total_length += b_curves_data[i]->getLength();
+    }
+    if (has_a_curves) {
+        total_length += clut->getLength();
+        for (size_t i = 0; i < kNumChannels; ++i) {
+            total_length += a_curves_data[i]->getLength();
+        }
+    }
+    sp<DataStruct> dataStruct = new DataStruct(total_length);
+    dataStruct->write32(Endian_SwapBE32(type));             // Type signature
+    dataStruct->write32(0);                                 // Reserved
+    dataStruct->write8(kNumChannels);                       // Input channels
+    dataStruct->write8(kNumChannels);                       // Output channels
+    dataStruct->write16(0);                                 // Reserved
+    dataStruct->write32(Endian_SwapBE32(b_curves_offset));  // B curve offset
+    dataStruct->write32(Endian_SwapBE32(0));                // Matrix offset (ignored)
+    dataStruct->write32(Endian_SwapBE32(0));                // M curve offset (ignored)
+    dataStruct->write32(Endian_SwapBE32(clut_offset));      // CLUT offset
+    dataStruct->write32(Endian_SwapBE32(a_curves_offset));  // A curve offset
+    for (size_t i = 0; i < kNumChannels; ++i) {
+        if (dataStruct->write(b_curves_data[i]->getData(), b_curves_data[i]->getLength())) {
+            return dataStruct;
+        }
+    }
+    if (has_a_curves) {
+        dataStruct->write(clut->getData(), clut->getLength());
+        for (size_t i = 0; i < kNumChannels; ++i) {
+            dataStruct->write(a_curves_data[i]->getData(), a_curves_data[i]->getLength());
+        }
+    }
+    return dataStruct;
+}
+
+sp<DataStruct> IccHelper::writeIccProfile(ultrahdr_transfer_function tf,
+                                          ultrahdr_color_gamut gamut) {
+    ICCHeader header;
+
+    std::vector<std::pair<uint32_t, sp<DataStruct>>> tags;
+
+    // Compute profile description tag
+    std::string desc = get_desc_string(tf, gamut);
+
+    tags.emplace_back(kTAG_desc, write_text_tag(desc.c_str()));
+
+    Matrix3x3 toXYZD50;
+    switch (gamut) {
+        case ULTRAHDR_COLORGAMUT_BT709:
+            toXYZD50 = kSRGB;
+            break;
+        case ULTRAHDR_COLORGAMUT_P3:
+            toXYZD50 = kDisplayP3;
+            break;
+        case ULTRAHDR_COLORGAMUT_BT2100:
+            toXYZD50 = kRec2020;
+            break;
+        default:
+            // Should not fall here.
+            return new DataStruct(0);
+    }
+
+    // Compute primaries.
+    {
+        tags.emplace_back(kTAG_rXYZ,
+                write_xyz_tag(toXYZD50.vals[0][0], toXYZD50.vals[1][0], toXYZD50.vals[2][0]));
+        tags.emplace_back(kTAG_gXYZ,
+                write_xyz_tag(toXYZD50.vals[0][1], toXYZD50.vals[1][1], toXYZD50.vals[2][1]));
+        tags.emplace_back(kTAG_bXYZ,
+                write_xyz_tag(toXYZD50.vals[0][2], toXYZD50.vals[1][2], toXYZD50.vals[2][2]));
+    }
+
+    // Compute white point tag (must be D50)
+    tags.emplace_back(kTAG_wtpt, write_xyz_tag(kD50_x, kD50_y, kD50_z));
+
+    // Compute transfer curves.
+    if (tf != ULTRAHDR_TF_PQ) {
+        if (tf == ULTRAHDR_TF_HLG) {
+            std::vector<uint8_t> trc_table;
+            trc_table.resize(kTrcTableSize * 2);
+            for (uint32_t i = 0; i < kTrcTableSize; ++i) {
+                float x = i / (kTrcTableSize - 1.f);
+                float y = hlgOetf(x);
+                y *= compute_tone_map_gain(tf, y);
+                float_to_table16(y, &trc_table[2 * i]);
+            }
+
+            tags.emplace_back(kTAG_rTRC,
+                    write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data())));
+            tags.emplace_back(kTAG_gTRC,
+                    write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data())));
+            tags.emplace_back(kTAG_bTRC,
+                    write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data())));
+        } else {
+            tags.emplace_back(kTAG_rTRC, write_trc_tag_for_linear());
+            tags.emplace_back(kTAG_gTRC, write_trc_tag_for_linear());
+            tags.emplace_back(kTAG_bTRC, write_trc_tag_for_linear());
+        }
+    }
+
+    // Compute CICP.
+    if (tf == ULTRAHDR_TF_HLG || tf == ULTRAHDR_TF_PQ) {
+        // The CICP tag is present in ICC 4.4, so update the header's version.
+        header.version = Endian_SwapBE32(0x04400000);
+
+        uint32_t color_primaries = 0;
+        if (gamut == ULTRAHDR_COLORGAMUT_BT709) {
+            color_primaries = kCICPPrimariesSRGB;
+        } else if (gamut == ULTRAHDR_COLORGAMUT_P3) {
+            color_primaries = kCICPPrimariesP3;
+        }
+
+        uint32_t transfer_characteristics = 0;
+        if (tf == ULTRAHDR_TF_SRGB) {
+            transfer_characteristics = kCICPTrfnSRGB;
+        } else if (tf == ULTRAHDR_TF_LINEAR) {
+            transfer_characteristics = kCICPTrfnLinear;
+        } else if (tf == ULTRAHDR_TF_PQ) {
+            transfer_characteristics = kCICPTrfnPQ;
+        } else if (tf == ULTRAHDR_TF_HLG) {
+            transfer_characteristics = kCICPTrfnHLG;
+        }
+        tags.emplace_back(kTAG_cicp, write_cicp_tag(color_primaries, transfer_characteristics));
+    }
+
+    // Compute A2B0.
+    if (tf == ULTRAHDR_TF_PQ) {
+        std::vector<uint8_t> a2b_grid;
+        a2b_grid.resize(kGridSize * kGridSize * kGridSize * kNumChannels * 2);
+        size_t a2b_grid_index = 0;
+        for (uint32_t r_index = 0; r_index < kGridSize; ++r_index) {
+            for (uint32_t g_index = 0; g_index < kGridSize; ++g_index) {
+                for (uint32_t b_index = 0; b_index < kGridSize; ++b_index) {
+                    float rgb[3] = {
+                            r_index / (kGridSize - 1.f),
+                            g_index / (kGridSize - 1.f),
+                            b_index / (kGridSize - 1.f),
+                    };
+                    compute_lut_entry(toXYZD50, rgb);
+                    float_XYZD50_to_grid16_lab(rgb, &a2b_grid[a2b_grid_index]);
+                    a2b_grid_index += 6;
+                }
+            }
+        }
+        const uint8_t* grid_16 = reinterpret_cast<const uint8_t*>(a2b_grid.data());
+
+        uint8_t grid_points[kNumChannels];
+        for (size_t i = 0; i < kNumChannels; ++i) {
+            grid_points[i] = kGridSize;
+        }
+
+        auto a2b_data = write_mAB_or_mBA_tag(kTAG_mABType,
+                                             /* has_a_curves */ true,
+                                             grid_points,
+                                             grid_16);
+        tags.emplace_back(kTAG_A2B0, std::move(a2b_data));
+    }
+
+    // Compute B2A0.
+    if (tf == ULTRAHDR_TF_PQ) {
+        auto b2a_data = write_mAB_or_mBA_tag(kTAG_mBAType,
+                                             /* has_a_curves */ false,
+                                             /* grid_points */ nullptr,
+                                             /* grid_16 */ nullptr);
+        tags.emplace_back(kTAG_B2A0, std::move(b2a_data));
+    }
+
+    // Compute copyright tag
+    tags.emplace_back(kTAG_cprt, write_text_tag("Google Inc. 2022"));
+
+    // Compute the size of the profile.
+    size_t tag_data_size = 0;
+    for (const auto& tag : tags) {
+        tag_data_size += tag.second->getLength();
+    }
+    size_t tag_table_size = kICCTagTableEntrySize * tags.size();
+    size_t profile_size = kICCHeaderSize + tag_table_size + tag_data_size;
+
+    // Write the header.
+    header.data_color_space = Endian_SwapBE32(Signature_RGB);
+    header.pcs = Endian_SwapBE32(tf == ULTRAHDR_TF_PQ ? Signature_Lab : Signature_XYZ);
+    header.size = Endian_SwapBE32(profile_size);
+    header.tag_count = Endian_SwapBE32(tags.size());
+
+    sp<DataStruct> dataStruct = new DataStruct(profile_size);
+    if (!dataStruct->write(&header, sizeof(header))) {
+        ALOGE("writeIccProfile(): error in header");
+        return dataStruct;
+    }
+
+    // Write the tag table. Track the offset and size of the previous tag to
+    // compute each tag's offset. An empty SkData indicates that the previous
+    // tag is to be reused.
+    uint32_t last_tag_offset = sizeof(header) + tag_table_size;
+    uint32_t last_tag_size = 0;
+    for (const auto& tag : tags) {
+        last_tag_offset = last_tag_offset + last_tag_size;
+        last_tag_size = tag.second->getLength();
+        uint32_t tag_table_entry[3] = {
+                Endian_SwapBE32(tag.first),
+                Endian_SwapBE32(last_tag_offset),
+                Endian_SwapBE32(last_tag_size),
+        };
+        if (!dataStruct->write(tag_table_entry, sizeof(tag_table_entry))) {
+            ALOGE("writeIccProfile(): error in writing tag table");
+            return dataStruct;
+        }
+    }
+
+    // Write the tags.
+    for (const auto& tag : tags) {
+        if (!dataStruct->write(tag.second->getData(), tag.second->getLength())) {
+            ALOGE("writeIccProfile(): error in writing tags");
+            return dataStruct;
+        }
+    }
+
+    return dataStruct;
+}
+
+} // namespace android::ultrahdr
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