fix: Add framebuffer release/realloc and improved lazy indexing (#2563)

lib/miniz/src/InflateStream.h

@@ -0,0 +1,95 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+// Forward declaration keeps miniz out of consumer translation units; the
+// decompressor state is heap-allocated in the .cpp where the type is complete.
+struct tinfl_decompressor_tag;
+
+// Streaming deflate decompressor wrapping miniz's tinfl.
+//
+// Replaces the uzlib-backed InflateReader on the throughput paths (EPUB zip
+// entries, PNG IDAT). tinfl decodes via lookup tables where uzlib walks the
+// Huffman tree bit-by-bit -- several times faster on this CPU -- at the cost
+// of a larger decompressor state (~11KB, transient for the scope of the
+// stream; taken from the lent framebuffer bytes via buildscratch::claim()
+// when a FrameBufferLoan is active, heap otherwise). FontDecompressor
+// intentionally stays on InflateReader:
+// its one-shot flash-resident group decompressions are tiny, and the render
+// path should not carry the extra state allocation.
+//
+// Two modes:
+//   init(false) -- one-shot: the destination buffer holds the ENTIRE output,
+//                  so back-references resolve inside it and no 32KB window is
+//                  allocated. read()/readAtMost() must be driven with
+//                  contiguous, forward-only slices of that one buffer
+//                  (a single read(dest, totalSize) is the common case).
+//   init(true)  -- streaming: allocates a 32KB window; output can go to any
+//                  buffer in any-sized chunks across calls.
+//
+// Input is either a single contiguous buffer (setSource) or pulled on demand
+// through a fill callback (setFill): return the number of bytes available and
+// point *data at them (valid until the next fill call); return 0 at end of
+// input. Call setZlibWrapped() before the first read when the stream has a
+// zlib header (e.g. PNG IDAT).
+class InflateStream {
+ public:
+  enum class Status {
+    Ok,     // Output buffer full; more decompressed data remains.
+    Done,   // Stream ended cleanly. produced may be < maxLen.
+    Error,  // Corrupt/truncated stream, or decompression failed.
+  };
+
+  using FillFn = size_t (*)(void* ctx, const uint8_t** data);
+
+  InflateStream() = default;
+  ~InflateStream();
+  InflateStream(const InflateStream&) = delete;
+  InflateStream& operator=(const InflateStream&) = delete;
+
+  // Allocate decompressor state (and the 32KB window when streaming) and reset
+  // stream state. Reuses existing allocations on repeated calls. Returns false
+  // on OOM.
+  bool init(bool streaming);
+
+  // Free the decompressor state and window.
+  void deinit();
+
+  // Provide the entire compressed input as one contiguous buffer.
+  void setSource(const uint8_t* src, size_t len);
+
+  // Provide compressed input on demand. ctx is passed back to fn verbatim.
+  void setFill(FillFn fn, void* ctx);
+
+  // Declare the input zlib-wrapped (2-byte header + trailing adler32).
+  void setZlibWrapped() { zlibWrapped = true; }
+
+  // Decompress exactly len bytes into dest. Returns false if the stream ends
+  // or errors before producing len bytes.
+  bool read(uint8_t* dest, size_t len);
+
+  // Decompress up to maxLen bytes into dest; *produced gets the byte count.
+  Status readAtMost(uint8_t* dest, size_t maxLen, size_t* produced);
+
+ private:
+  tinfl_decompressor_tag* state = nullptr;  // ~11KB: heap, or inside the claimed build scratch
+  uint8_t* window = nullptr;                // 32KB ring, streaming mode only
+  uint8_t* arenaBase = nullptr;             // non-null when state/window live in lent framebuffer bytes
+  size_t windowPos = 0;                     // ring write cursor
+  // Decompressed-but-undelivered region of the window (tinfl can overshoot the
+  // caller's requested length; the overshoot waits here for the next read).
+  size_t pendingStart = 0;
+  size_t pendingLen = 0;
+
+  const uint8_t* inPtr = nullptr;
+  size_t inAvail = 0;
+  FillFn fill = nullptr;
+  void* fillCtx = nullptr;
+  bool inputExhausted = false;
+  bool zlibWrapped = false;
+  bool finished = false;
+
+  // One-shot mode: tinfl needs the output buffer start for back-references.
+  uint8_t* oneShotStart = nullptr;
+};