Fixing adler32 & crc32, and adding block-reading system for them, instead of reading the whole file.

1 files changed, 28 insertions, 12 deletions

diff --git a/lib/LuaHandle.cc b/lib/LuaHandle.cc
index 4456e13..cef3135 100644
--- a/lib/LuaHandle.cc
+++ b/lib/LuaHandle.cc
@@ -275,28 +275,37 @@ int sLuaHandle::readfile(lua_State * __L) {
     return 1;
 }
 
+#define MAXCHUNKSIZE 65536
+
 int sLuaHandle::adler32(lua_State * __L) {
     Lua * L = Lua::find(__L);
     int n = L->gettop();
     Handle * h;
     Byte * buf;
+    ssize_t tg, blk;
 
     if (n != 1) {
         L->error("Incorrect arguments to function `adler32'");
     }
 
     h = L->recast<Handle>();
-    if (h->GetSize() < 0) return 0;
+    tg = h->GetSize();
+    if (tg < 0) return 0;
 
     h->seek(0);
     
-    buf = (Byte *) malloc(h->GetSize());
+    buf = (Byte *) malloc(MAXCHUNKSIZE);
     Uint32 adler = ::adler32(0L, Z_NULL, 0);
-     
-    adler = ::adler32(adler, buf, h->GetSize());
-
-    L->push((lua_Number) adler);
+    
+    while (tg > 0) {
+        blk = MIN(MAXCHUNKSIZE, tg);
+        h->read(buf, blk);
+        tg -= blk;
+        adler = ::adler32(adler, buf, blk);
+    }
     free(buf);
+    
+    L->push((lua_Number) adler);
 
     return 1;
 }
@@ -306,23 +315,30 @@ int sLuaHandle::crc32(lua_State * __L) {
     int n = L->gettop();
     Handle * h;
     Byte * buf;
+    ssize_t tg, blk;
 
     if (n != 1) {
         L->error("Incorrect arguments to function `crc32'");
     }
 
     h = L->recast<Handle>();
-    if (h->GetSize() < 0) return 0;
+    tg = h->GetSize();
+    if (tg < 0) return 0;
 
     h->seek(0);
     
-    buf = (Byte *) malloc(h->GetSize());
+    buf = (Byte *) malloc(MAXCHUNKSIZE);
     Uint32 crc = ::crc32(0L, Z_NULL, 0);
-     
-    crc = ::crc32(crc, buf, h->GetSize());
-
-    L->push((lua_Number) crc);
+    
+    while (tg > 0) {
+        blk = MIN(MAXCHUNKSIZE, tg);
+        h->read(buf, blk);
+        tg -= blk;
+        crc = ::crc32(crc, buf, blk);
+    }
     free(buf);
+    
+    L->push((lua_Number) crc);
 
     return 1;
 }