[zmat] make zlib/gzip encoder/decoder use java for octave, update octavezmat.m

Author: fangq

gzipdecode.m

@@ -15,7 +15,7 @@
 %
 % input:
 %      input: a string, int8/uint8 vector or numerical array to store the GZIP-compressed data
-%      info (optional): a struct produced by the zmat/lz4hcencode function during
+%      info (optional): a struct produced by the zmat/gzipencode function during
 %            compression; if not given, the inputs/outputs will be treated as a
 %            1-D vector
 %
@@ -46,28 +46,53 @@
         [varargout{1:nargout}] = zmat(varargin{1}, 0, 'gzip', varargin{2:end});
     end
     return
-elseif (isoctavemesh)
-    [varargout{1:nargout}] = octavezmat(varargin{1}, 0, 'gzip');
-    return
 end
-error(javachk('jvm'));
 
 if (ischar(varargin{1}))
     varargin{1} = uint8(varargin{1});
 end
 
 input = typecast(varargin{1}(:)', 'uint8');
 
-gzip = java.util.zip.GZIPInputStream(java.io.ByteArrayInputStream(input));
-buffer = java.io.ByteArrayOutputStream();
-org.apache.commons.io.IOUtils.copy(gzip, buffer);
-gzip.close();
+if (~usejava('jvm'))
+    if (nargin > 1)
+        [varargout{1:nargout}] = octavezmat(varargin{1}, varargin{2}, 'gzip');
+    else
+        [varargout{1:nargout}] = octavezmat(varargin{1}, 0, 'gzip');
+    end
+    return
+end
 
-if (nargout > 0)
-    varargout{1} = typecast(buffer.toByteArray(), 'uint8')';
-    if (nargin > 1 && isstruct(varargin{2}) && isfield(varargin{2}, 'type'))
-        inputinfo = varargin{2};
-        varargout{1} = typecast(varargout{1}, inputinfo.type);
-        varargout{1} = reshape(varargout{1}, inputinfo.size);
+if (isoctavemesh)
+    % Octave with Java: write/read bytes one at a time
+    n = numel(input);
+    inputBaos = javaObject('java.io.ByteArrayOutputStream', n);
+    for i = 1:n
+        inputBaos.write(int32(input(i)));
+    end
+    bais = javaObject('java.io.ByteArrayInputStream', inputBaos.toByteArray());
+    gzis = javaObject('java.util.zip.GZIPInputStream', bais);
+    baos = javaObject('java.io.ByteArrayOutputStream');
+    while true
+        b = gzis.read();
+        if (b < 0)
+            break
+        end
+        baos.write(b);
     end
+    gzis.close();
+    varargout{1} = typecast(baos.toByteArray(), 'uint8')';
+else
+    % MATLAB with Java: use IOUtils for efficient copy
+    gzip = java.util.zip.GZIPInputStream(java.io.ByteArrayInputStream(input));
+    buffer = java.io.ByteArrayOutputStream();
+    org.apache.commons.io.IOUtils.copy(gzip, buffer);
+    gzip.close();
+    varargout{1} = typecast(buffer.toByteArray(), 'uint8')';
+end
+
+if (nargin > 1 && isstruct(varargin{2}) && isfield(varargin{2}, 'type'))
+    inputinfo = varargin{2};
+    varargout{1} = typecast(varargout{1}, inputinfo.type);
+    varargout{1} = reshape(varargout{1}, inputinfo.size);
 end

gzipencode.m

@@ -40,14 +40,11 @@
 if ((exist('zmat', 'file') == 2 || exist('zmat', 'file') == 3) && (isempty(nozmat) || nozmat == 0))
     [varargout{1:nargout}] = zmat(varargin{1}, 1, 'gzip');
     return
-elseif (isoctavemesh)
-    [varargout{1:nargout}] = octavezmat(varargin{1}, 1, 'gzip');
-    return
 end
 
-error(javachk('jvm'));
-
 input = varargin{1}(:)';
+inputinfo = struct('type', class(varargin{1}), 'size', size(varargin{1}), 'method', 'gzip', 'status', 0);
+
 if (ischar(input))
     input = uint8(input);
 elseif (isa(input, 'string'))
@@ -56,15 +53,30 @@
     input = typecast(input, 'uint8');
 end
 
-input = typecast(input, 'uint8');
-
-buffer = java.io.ByteArrayOutputStream();
-gzip = java.util.zip.GZIPOutputStream(buffer);
-gzip.write(input, 0, numel(input));
-gzip.close();
+if (~usejava('jvm'))
+    [varargout{1:nargout}] = octavezmat(varargin{1}, 1, 'gzip');
+    return
+end
 
-varargout{1} = typecast(buffer.toByteArray(), 'uint8')';
+if (isoctavemesh)
+    % Octave with Java: write bytes one at a time
+    baos = javaObject('java.io.ByteArrayOutputStream');
+    gzos = javaObject('java.util.zip.GZIPOutputStream', baos);
+    for i = 1:numel(input)
+        gzos.write(int32(input(i)));
+    end
+    gzos.finish();
+    gzos.close();
+    varargout{1} = typecast(baos.toByteArray(), 'uint8')';
+else
+    % MATLAB with Java: direct array write
+    buffer = java.io.ByteArrayOutputStream();
+    gzip = java.util.zip.GZIPOutputStream(buffer);
+    gzip.write(input, 0, numel(input));
+    gzip.close();
+    varargout{1} = typecast(buffer.toByteArray(), 'uint8')';
+end
 
 if (nargout > 1)
-    varargout{2} = struct('type', class(varargin{1}), 'size', size(varargin{1}), 'method', 'gzip', 'status', 0);
+    varargout{2} = inputinfo;
 end