Optimize MapBuffer representation (#57361)#57361
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Summary: Adds two new MapBuffer entry types, `IntBuffer` and `DoubleBuffer`, for storing homogeneous arrays of ints and doubles compactly in the dynamic data section. Unlike `Map` / map lists, these carry no per-element key/type overhead: a batch of N values costs ~N*elementSize bytes plus a single 4-byte count prefix instead of N 12-byte buckets. The bucket value holds the offset of the array within the dynamic data section. Covers the full surface: the C++ reader (`MapBuffer::getIntBuffer` / `getDoubleBuffer`), the C++ builder (`MapBufferBuilder::putIntBuffer` / `putDoubleBuffer`), and the Kotlin reader API (`MapBuffer.getIntBuffer` / `getDoubleBuffer`, `Entry.intBufferValue` / `doubleBufferValue`). The `DataType` enum gains `IntBuffer = 6` and `DoubleBuffer = 7`, kept in sync across C++ and Kotlin. Changelog: [General][Added] - Add `IntBuffer` and `DoubleBuffer` entry types to MapBuffer for compact homogeneous int/double arrays Differential Revision: D109848476
Summary: Introduces a dedicated `MapBufferList` `DataType` for an ordered array of nested MapBuffers, instead of overloading the `Map` type for lists. This makes a list of MapBuffers self-describing and distinguishable from a single nested `Map` (they were byte-distinct in payload but previously shared the `Map` type tag). Updates the C++ builder (`putMapBufferList`), the Kotlin `MapBuffer` interface, `ReadableMapBuffer`, and `WritableMapBuffer`, and adds cross-language JNI round-trip coverage in the serialization instrumentation test. Changelog: [Android][Added] - Add a dedicated `MapBufferList` type to `MapBuffer` for ordered lists of nested `MapBuffer`s Differential Revision: D109848477
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Summary: Pull Request resolved: react#57361 Broadens the former header-shrink change into a single representation-optimization commit for MapBuffer. It bundles three layout optimizations that were previously split: (1) the header is reduced to a single 2-byte `count` field; (2) multi-byte values are read via `memcpy` so unaligned access is well-defined on all platforms; (3) every dynamic-data entry (`String`, `Map`, `MapBufferList`, `IntBuffer`, `DoubleBuffer`) packs its `[offset][byteLength]` into the bucket's 8-byte value instead of writing an in-band length prefix into the dynamic data section. Net effect: 4 fewer bytes per dynamic entry, one fewer indirection on read (the length is already in the bucket), and every dynamic entry becomes self-delimiting from its bucket alone. No public API change — only the internal serialized representation. Changelog: [Internal] Differential Revision: D109848478
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Summary:
Broadens the former header-shrink change into a single representation-optimization commit for MapBuffer. It bundles three layout optimizations that were previously split: (1) the header is reduced to a single 2-byte
countfield; (2) multi-byte values are read viamemcpyso unaligned access is well-defined on all platforms; (3) every dynamic-data entry (String,Map,MapBufferList,IntBuffer,DoubleBuffer) packs its[offset][byteLength]into the bucket's 8-byte value instead of writing an in-band length prefix into the dynamic data section.Net effect: 4 fewer bytes per dynamic entry, one fewer indirection on read (the length is already in the bucket), and every dynamic entry becomes self-delimiting from its bucket alone. No public API change — only the internal serialized representation.
Changelog: [Internal]
Differential Revision: D109848478