Initial commit for GitHub migration based on spice2x-25-03-03

2026-08-02 23:00:42 -07:00 · 2025-03-10 19:16:49 -07:00
parent 94af8d32c9
commit ed8c72852f
1008 changed files with 296815 additions and 0 deletions
@@ -0,0 +1,140 @@
+#pragma once
+
+#include <queue>
+#include <cstdint>
+
+namespace acio2emu::detail {
+    class InflateTransformer {
+    private:
+        std::queue<uint8_t> output_;
+
+        uint8_t flags_ = 0, flag_shift_ = 0;
+
+        uint8_t window_[85] = {};
+        int window_offset_  = 81;
+
+        enum class inflateStep {
+            readFlags,
+            processFlags,
+            copyStored,
+            copyFromWindow,
+        } step_ = inflateStep::readFlags;
+
+        void window_put_(uint8_t b) {
+            window_[window_offset_++] = b;
+            window_offset_ %= sizeof(window_);
+        }
+
+        uint8_t window_get_(int offset) {
+            return window_[offset % sizeof(window_)];
+        }
+
+    public:
+        void put(uint8_t b) {
+            auto consumed = false;
+
+            while (true) {
+                switch (step_) {
+                case inflateStep::readFlags:
+                    if (consumed) {
+                        // need more data
+                        return;
+                    }
+                    consumed = true;
+
+                    flags_ = b;
+                    flag_shift_ = 0;
+
+                    step_ = inflateStep::processFlags;
+                    break;
+
+                case inflateStep::processFlags:
+                    // have we processed every flag?
+                    if (flag_shift_ > 6) {
+                        step_ = inflateStep::readFlags;
+                        break;
+                    }
+
+                    if (flags_ & (1 << flag_shift_)) {
+                        flag_shift_++;
+
+                        if (flags_ & (1 << flag_shift_)) {
+                            // emit 0xAA when both bits are set
+                            output_.push(0xAA);
+                        }
+                    else {
+                        // copy from the window when only the lower bit is set
+                        step_ = inflateStep::copyFromWindow;
+                    }
+                }
+                else {
+                    step_ = inflateStep::copyStored;
+                }
+                flag_shift_++;
+
+                break;
+
+                case inflateStep::copyFromWindow: {
+                    if (consumed) {
+                        // need more data
+                        return;
+                    }
+                    consumed = true;
+
+                    // determine the match size, default is 2-bytes
+                    auto offset = b;
+                    auto size = 2;
+
+                    if (offset >= 0xAA) {
+                        // 4-byte match
+                        size = 4;
+                        offset -= 0xAB;
+                    }
+                    else if (offset >= 0x55) {
+                        // 3-byte match
+                        size = 3;
+                        offset -= 0x55;
+                    }
+
+                    for (auto i = 0; i < size; i ++) {
+                        auto cur = window_get_(offset + i);
+
+                        window_put_(cur);
+                        output_.push(cur);
+                    }
+
+                    // continue processing flags
+                    step_ = inflateStep::processFlags;  
+                    break;
+                }
+
+                case inflateStep::copyStored:
+                    if (consumed) {
+                        // need more data
+                        return;
+                    }
+                    consumed = true;
+
+                    window_put_(b);
+                    output_.push(b);
+
+                    // continue processing flags
+                    step_ = inflateStep::processFlags;  
+                    break;
+                }
+            }
+        }
+        
+        int get() {
+            if (output_.empty()) {
+                // output queue is empty
+                return -1;
+            }
+
+            auto b = output_.front();
+            output_.pop();
+
+            return b;
+        }
+    };
+}