a compression tool useful with constrained memory

@@ -3,6 +3,14 @@
  *
  * A library (prem/malprem) and a cli frontend to it (pres)
  *
+ * version 0.2015-04-27
+ *         removed undue data stream size limitations,
+ *         now it should work for up to 2GB files,
+ *         bigger streams will be compressed alright but
+ *         the diagnostic messages could become wrong after 2GB
+ * version 0.2015-04-26
+ *         initial public release
+ *
  * Usage: pres [-dcfFqii] [file ...]
  * Flags:
  *      -d:         Decompress instead of compressing

@@ -246,8 +254,8 @@
     exit(exit_stat);
 }
 
-long int enk; /* input data length */
-long int elk; /* compressed length */
+unsigned long int enk; /* input data length */
+unsigned long int elk; /* compressed length */
 
 /*
  * Compressing input to output (one file)

@@ -267,9 +275,10 @@
         exit( 1 );
     }
     enk = elk = 0;
-    for( ;; ){
+    b_n = 0;
+    for( ;; ++b_n ){
+ /* in output we roll over every 2^16 blocks regardless the b_n type size */
         d = enb;
-        b_n = enk / BLON; /* the future block number */
         /* fill the output buffer */
         while( d - enb < BLON && (c=getchar()) != EOF ){
             ++enk;

@@ -311,10 +320,10 @@
     /*
      * tell the result
      */
-    if(wcat_flg == 0 && !quiet) {
-        fprintf( stderr, "Compression: %d%%",
-                enk > 0 ?
-                ( (100 * ( enk - elk )) / enk ) :
+    if(wcat_flg == 0 && !quiet) { long dif = (long)enk-(long)elk;
+        fprintf( stderr, "Compression: %d%%",
+                enk ?
+                (int)((dif>21474836)?(dif/((long)enk/100)):(100*dif/(long)enk)) :
                 0 );
     }
     if(elk > enk)    /* exit(2) if no compression */

@@ -439,12 +448,13 @@
                 continue;
             }
         }
-        oblk = it_blk + 1;
+        oblk = (it_blk + 1)&65535; /* ensure rolling over every 2^16 blocks */
         lon = it_lon;
         if( lon == BLON ){ /* not the last block */
-            if( (i=serch()) == EOF    /* end ??? */
-             || it_blk != oblk )  /* out of order */
-                    continue; /* do not trust this block */
+            if( ((i=serch()) == EOF    /* end ??? */
+                 || it_blk != oblk)    /* out of order */
+                 && !ignore )
+                    continue; /* do not trust the freshly uncompressed block */
         } else { /* looks like the last one */
             if( ignore && (i=serch()) != EOF ){
                 /* not last, look further! */

@@ -457,8 +467,8 @@
                     continue; /* ignoring the "last" block indication */
             }
         }
-        if( (j=oblk-b_blk-1) != 0 ){
-            /* the next block number in order, but here there was a skip */
+        if( (j=oblk-((b_blk+1)&65535)) != 0 ){
+            /* there was a skip */
             if( fseek( stdout, (long)oblk*(long)BLON, 0 ) < 0 )
                 /* can not seek (pipe) */
                 if( j > 0 && j <= 10 ) /* skipped blocks

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