Add PPI header recognition tests

src/assets/ppi_header.cpp

@@ -0,0 +1,73 @@
+#include "assets/ppi_header.h"
+
+#include "foundation/binary_stream.h"
+
+namespace pp::assets {
+
+namespace {
+
+[[nodiscard]] pp::foundation::Result<std::uint32_t> read_u32(pp::foundation::ByteReader& reader) noexcept
+{
+    return reader.read_u32_le();
+}
+
+}
+
+pp::foundation::Result<PpiHeaderInfo> parse_ppi_header(std::span<const std::byte> bytes) noexcept
+{
+    if (bytes.size() < ppi_header_size) {
+        return pp::foundation::Result<PpiHeaderInfo>::failure(
+            pp::foundation::Status::out_of_range("PPI header is truncated"));
+    }
+
+    pp::foundation::ByteReader reader(bytes.subspan(0, ppi_header_size));
+    const auto magic = reader.read_bytes(4);
+    if (!magic || magic.value()[0] != std::byte { 'P' } || magic.value()[1] != std::byte { 'P' }
+        || magic.value()[2] != std::byte { 'I' } || magic.value()[3] != std::byte { 0 }) {
+        return pp::foundation::Result<PpiHeaderInfo>::failure(
+            pp::foundation::Status::invalid_argument("PPI header magic is invalid"));
+    }
+
+    PpiHeaderInfo info;
+    const auto doc_major = read_u32(reader);
+    const auto doc_minor = read_u32(reader);
+    const auto soft_major = read_u32(reader);
+    const auto soft_minor = read_u32(reader);
+    const auto soft_fix = read_u32(reader);
+    const auto soft_build = read_u32(reader);
+    const auto thumb_width = read_u32(reader);
+    const auto thumb_height = read_u32(reader);
+    const auto thumb_components = read_u32(reader);
+    if (!doc_major || !doc_minor || !soft_major || !soft_minor || !soft_fix || !soft_build
+        || !thumb_width || !thumb_height || !thumb_components) {
+        return pp::foundation::Result<PpiHeaderInfo>::failure(
+            pp::foundation::Status::out_of_range("PPI header is truncated"));
+    }
+
+    info.document_version = { doc_major.value(), doc_minor.value() };
+    info.software_version = {
+        soft_major.value(),
+        soft_minor.value(),
+        soft_fix.value(),
+        soft_build.value(),
+    };
+    info.thumbnail = {
+        thumb_width.value(),
+        thumb_height.value(),
+        thumb_components.value(),
+    };
+
+    if (info.document_version.major != 0 || info.document_version.minor < 1) {
+        return pp::foundation::Result<PpiHeaderInfo>::failure(
+            pp::foundation::Status::invalid_argument("PPI document version is unsupported"));
+    }
+
+    if (info.thumbnail.width != 128 || info.thumbnail.height != 128 || info.thumbnail.components != 4) {
+        return pp::foundation::Result<PpiHeaderInfo>::failure(
+            pp::foundation::Status::invalid_argument("PPI thumbnail descriptor is invalid"));
+    }
+
+    return pp::foundation::Result<PpiHeaderInfo>::success(info);
+}
+
+}