MBMNET-App v2.8.2: Quellcode (GPLv3)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-18 17:05:44 +02:00
commit d264cd93cd
42 changed files with 7054 additions and 0 deletions
@@ -0,0 +1,58 @@
+// Entpacker für das "Backwards LZ"-Format, mit dem Nintendo die .code von
+// Systemmodulen komprimiert. Luma3DS wendet code.ips-Patches auf die
+// ENTPACKTE .code an, deshalb müssen wir genauso rechnen.
+#include <string.h>
+#include "blz.h"
+
+static u32 read32(const u8 *p) { return p[0] | (p[1] << 8) | (p[2] << 16) | ((u32)p[3] << 24); }
+
+bool blz_looks_compressed(const u8 *buf, u32 size)
+{
+    if (size < 8) return false;
+    u32 enc = read32(buf + size - 8);
+    u32 add = read32(buf + size - 4);
+    u32 hdr = enc >> 24;
+    u32 enclen = enc & 0xFFFFFF;
+    return hdr >= 8 && hdr <= 0x10 && enclen >= hdr && enclen <= size && add > 0 && add < 0x1000000;
+}
+
+u32 blz_decompressed_size(const u8 *buf, u32 size)
+{
+    return size + read32(buf + size - 4);
+}
+
+// buf muss mindestens blz_decompressed_size() Bytes groß sein.
+// Daten liegen am Anfang von buf, es wird rückwärts in-place entpackt.
+bool blz_decompress(u8 *buf, u32 size)
+{
+    u32 enc = read32(buf + size - 8);
+    u32 hdr = enc >> 24;
+    u32 enclen = enc & 0xFFFFFF;
+    u32 outsize = blz_decompressed_size(buf, size);
+
+    u8 *src = buf + size - hdr;
+    u8 *srcEnd = buf + size - enclen;
+    u8 *dst = buf + outsize;
+
+    while (src > srcEnd) {
+        u8 flags = *--src;
+        for (int i = 0; i < 8 && src > srcEnd; i++, flags <<= 1) {
+            if (flags & 0x80) {
+                if (src - 2 < buf) return false;
+                u8 hi = *--src;
+                u8 lo = *--src;
+                u32 len = (hi >> 4) + 3;
+                u32 disp = (((hi & 0x0F) << 8) | lo) + 3;
+                for (u32 j = 0; j < len; j++) {
+                    if (dst - 1 < buf || dst - 1 + disp >= buf + outsize) return false;
+                    dst--;
+                    *dst = dst[disp];
+                }
+            } else {
+                if (dst - 1 < buf) return false;
+                *--dst = *--src;
+            }
+        }
+    }
+    return true;
+}