You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: CrossCutter.m
    path of file: ./repos/HDR_Toolbox/source_code/EnvironmentMaps
    
    the code of the file until where you have to start completion: function CrossCutter(img, cb_name, cb_format)
%
%        CrossCutter(img, cb_name, cb_format)
%
%
%        Input:
%           -img: input environment map encoded as a cubemap
%           -name: a string representing the prefix name for each face of
%            the cubemap. For example: 'output_cubemap' (default)
%           -format: the output format of each face of the cubemap. For
%           example: 'hdr' (default)
%        Output:
%           -ret: it is set to 1 if the function succeeded
%
%     Copyright (C) 2011  Francesco Banterle
% 
%     This program is free software: you can redistribute it and/or modify
%     it under the terms of the GNU General Public License as published by
%     the Free Software Foundation, either version 3 of the License, or
%     (at your option) any later version.
% 
%     This program is distributed in the hope that it will be useful,
%     but WITHOUT ANY WARRANTY; without even the implied warranty of
%     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%     GNU General Public License for more details.
% 
%     You should have received a copy of the GNU General Public License
%     along with this program.  If not, see <http://www.gnu.org/licenses/>.
%

if(~exist('cb_name', 'var'))
    cb_name = 'output_cube_map';
end

if(~exist('cb_format', 'var'))
    cb_name = 'hdr';
end

c = size(img, 2);

cubeSize = round(c / 3);

    
function CrossCutter(img, cb_name, cb_format)
%
%        CrossCutter(img, cb_name, cb_format)
%
%
%        Input:
%           -img: input environment map encoded as a cubemap
%           -name: a string representing the prefix name for each face of
%            the cubemap. For example: 'output_cubemap' (default)
%           -format: the output format of each face of the cubemap. For
%           example: 'hdr' (default)
%        Output:
%           -ret: it is set to 1 if the function succeeded
%
%     Copyright (C) 2011  Francesco Banterle
% 
%     This program is free software: you can redistribute it and/or modify
%     it under the terms of the GNU General Public License as published by
%     the Free Software Foundation, either version 3 of the License, or
%     (at your option) any later version.
% 
%     This program is distributed in the hope that it will be useful,
%     but WITHOUT ANY WARRANTY; without even the implied warranty of
%     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%     GNU General Public License for more details.
% 
%     You should have received a copy of the GNU General Public License
%     along with this program.  If not, see <http://www.gnu.org/licenses/>.
%

if(~exist('cb_name', 'var'))
    cb_name = 'output_cube_map';
end

if(~exist('cb_format', 'var'))
    cb_name = 'hdr';
end

c = size(img, 2);

cubeSize = round(c / 3);

%CUBE_POS_Y
imgPosY = img(1:cubeSize,(cubeSize+1):(2*cubeSize),:);
imgPosY = imrotate(imgPosY, -270);
hdrimwrite(imgPosY,[cb_name,'_POS_Y.',cb_format]);

%CUBE_POS_X
hdrimwrite(img((cubeSize+1)    :(2*cubeSize),(cubeSize+1):(2*cubeSize),:),[cb_name,'_POS_X.',cb_format]);

%CUBE_NEG_Y
imgNegY = img((2*cubeSize+1):(3*cubeSize),(cubeSize+1):(2*cubeSize),:);
hdrimwrite(imrotate(imgNegY,-90),[cb_name,'_NEG_Y.',cb_format]);

%CUBE_NEG_X
imgNegX = img((3*cubeSize+1):(4*cubeSize),(cubeSize+1):(2*cubeSize),:); 
for i=1:3
    imgNegX(:,:,i) = flipud(imgNegX(:,:,i));
    imgNegX(:,:,i) = fliplr(imgNegX(:,:,i));
end