Merge pull request #98 from adavies42/feature/unzip

Feature/unzip

q/unzip/unzip.q

@@ -437,12 +437,20 @@
       .finos.unzip.priv.parseNum cmp,
       {"v"$24 60 60 sv 1 1 2*2 sv'0 5 11 cut reverse .finos.unzip.priv.parseBits x}mtm,
       {.finos.util.ymd . 1980 0 0+2 sv'0 7 11 cut reverse .finos.unzip.priv.parseBits x}mdt,
-      .finos.unzip.priv.parseNum csz,
-      .finos.unzip.priv.parseNum usz,
       .finos.unzip.priv.parseNum nln,
       .finos.unzip.priv.parseNum xln
     from z;
 
+  if[r[`flg]`data_descriptor;
+      / data descriptor
+      r,:`crc`csz`usz!4 cut -12#x;
+      ];
+
+  r:update
+      .finos.unzip.priv.parseNum csz,
+      .finos.unzip.priv.parseNum usz
+    from r;
+
   r:update fnm:`$"c"$x y+til nln from r;
 
   r:update xfd:x y+nln+til xln from r;
@@ -495,7 +503,7 @@
 // @return long
 .finos.unzip.priv.ofcds:{
   c:hcount x;
-  r:{(not 0x504b0506~y 0)&x>y 1}[c]{(read1(x;y-z 1;4);1+z 1)}[x;c]/(0x00000000;0);
+  r:{(not 0x504b0506~y 0)&x>=y 1}[c]{(read1(x;y-z 1;4);1+z 1)}[x;c]/(0x00000000;0);
   $[0x504b0506~r 0;1+c-r 1;0N]}
 
 // Find offset of zip64 end of central directory locator signature in a zip vector.
@@ -598,6 +606,31 @@
           ecd64:.finos.unzip.priv.pecd64 .finos.unzip.priv.bytes[y;ecl64`cof;12+.finos.unzip.priv.parseNum .finos.unzip.priv.bytes[y;4+ecl64`cof;8]]];
       ecd];
 
+  / check for empty zip
+  if[not count cd;
+      :$[
+        `list=x;
+          ([name:0#`]size:0#0Ni;timestamp:0#0Np);
+        `unzip=x;
+          $[
+            -11h=type z;
+              [
+                .finos.log.error(string z),": file not found in archive";
+                'z;
+                ];
+            11h=type z;
+              [
+                {.finos.log.error(string x),": file not found in archive"}each z;
+                'first z;
+                ];
+            z~(::);
+              ((0#`)!())];
+        '`domain];
+    ];
+
+  / start of central directory
+  scd:$[-1=ecd`cof;ecd64;ecd]`cof;
+
   / parse central directory
   .finos.log.debug"parsing central directory";
   cd:.finos.unzip.priv.parse[(.finos.unzip.priv.pcd;.finos.unzip.priv.wcd);cd;count cd];
@@ -612,9 +645,16 @@
         1!select name:fnm,size:usz,timestamp:mdt+mtm from cd];
     `unzip=x;
       [
+        / calculate next offsets
+        cd:update nof:scd^next lof from cd;
+
         / apply file filter, if any
         if[not z~(::);
           cd:select from cd where fnm in z;
+          if[count e:exec(raze z)except fnm from cd;
+            {.finos.log.error(string x),": file not found in archive"}each e;
+            'first e;
+            ];
           ];
 
         / parse file data
@@ -630,15 +670,16 @@
               y:(exec min lof from cd)_y;
 
               / extract all files
-              .finos.unzip.priv.parse[(.finos.unzip.priv.pfd;.finos.unzip.priv.wfd;z);y;($[-1=ecd`cof;ecd64;ecd]`cof)-exec min lof from cd]];
+              .finos.unzip.priv.parse[(.finos.unzip.priv.pfd;.finos.unzip.priv.wfd;z);y;scd-exec min lof from cd]];
           [
             / extract each file mentioned in the central directory
-            / TODO probably over-reads (at least) the last file
             f:{[w;x;y;z]
               h:.finos.unzip.priv.split[w;0].finos.unzip.priv.bytes[x;y`lof;sum w];
               first .finos.unzip.priv.pfd[(.finos.unzip.priv.bytes[x;y`lof;z-y`lof];::);sum w;h]};
 
-            cd f[.finos.unzip.priv.wfd;y]'c^exec next lof from cd]];
+            / assume the end of the last file is the beginning of the central directory
+            / might be wrong if archive decryption header and/or archive extra data record are present?
+            cd f[.finos.unzip.priv.wfd;y]'exec nof from cd]];
 
         r:exec fnm!fdu from fd;
 
@@ -676,6 +717,7 @@
 
 // Set to true to extract files via file scan, rather than by using the
 //  central directory.
+// N.B. currently, will likely fail for data-descriptor-based archives
 .finos.unzip.filescan:0b
 
 // List files in an archive.