mirror of https://github.com/davisking/dlib.git
239 lines
8.3 KiB
C++
239 lines
8.3 KiB
C++
// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
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/*
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This is an example illustrating the use of the compress_stream and
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cmd_line_parser components from the dlib C++ Library.
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This example implements a simple command line compression utility.
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The output from the program when the -h option is given is:
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Usage: compress_stream_ex (-c|-d|-l) --in input_file --out output_file
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Options:
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-c Indicates that we want to compress a file.
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-d Indicates that we want to decompress a file.
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-h Display this help message.
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--in <arg> This option takes one argument which specifies the name of the
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file we want to compress/decompress.
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-l <arg> Set the compression level [1-3], 3 is max compression, default
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is 2.
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--out <arg> This option takes one argument which specifies the name of the
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output file.
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*/
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#include "dlib/compress_stream.h"
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#include "dlib/cmd_line_parser.h"
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#include <iostream>
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#include <fstream>
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#include <string>
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// I am making a typedefs for the versions of compress_stream I want to use.
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typedef dlib::compress_stream::kernel_1da cs1;
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typedef dlib::compress_stream::kernel_1ea cs2;
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typedef dlib::compress_stream::kernel_1ec cs3;
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using namespace std;
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using namespace dlib;
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int main(int argc, char** argv)
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{
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try
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{
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command_line_parser parser;
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// first I will define the command line options I want.
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// Add a -c option and tell the parser what the option is for.
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parser.add_option("c","Indicates that we want to compress a file.");
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parser.add_option("d","Indicates that we want to decompress a file.");
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// add a --in option that takes 1 argument
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parser.add_option("in","This option takes one argument which specifies the name of the file we want to compress/decompress.",1);
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// add a --out option that takes 1 argument
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parser.add_option("out","This option takes one argument which specifies the name of the output file.",1);
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parser.add_option("h","Display this help message.");
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parser.add_option("l","Set the compression level [1-3], 3 is max compression, default is 2.",1);
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// now I will parse the command line
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parser.parse(argc,argv);
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// Now I will use the parser to validate some things about the command line.
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// If any of the following checks fail then an exception will be thrown and it will
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// contain a message that tells the user what the problem was.
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// First I want to check that none of the options were given on the command line
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// more than once. To do this I define an array that contains the options
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// that shouldn't appear more than once and then I just call check_one_time_options()
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const char* one_time_opts[] = {"c", "d", "in", "out", "h", "l"};
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parser.check_one_time_options(one_time_opts);
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// Here I'm checking that the user didn't pick both the c and d options at the
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// same time.
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parser.check_incompatible_options("c", "d");
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// Here I'm checking that the argument to the l option is an integer in the range 1 to 3.
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// That is, it should be convertible to an int by dlib::string_assign and be either
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// 1, 2, or 3. Note that if you wanted to allow floating point values in the range 1 to
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// 3 then you could give a range 1.0 to 3.0 or explicitly supply a type of float or double
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// to the template argument of the check_option_arg_range() function.
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parser.check_option_arg_range("l", 1, 3);
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// The 'l' option is a sub-option of the 'c' option. That is, you can only select the
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// compression level when compressing. This command below checks that the listed
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// sub options are always given in the presence of their parent options.
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const char* c_sub_opts[] = {"l"};
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parser.check_sub_options("c", c_sub_opts);
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// check if the -h option was given on the command line
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if (parser.option("h"))
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{
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// display all the command line options
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cout << "Usage: compress_stream_ex (-c|-d|-l) --in input_file --out output_file\n";
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// This function prints out a nicely formatted list of
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// all the options the parser has
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parser.print_options(cout);
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cout << endl;
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return 0;
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}
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// Figure out what the compression level should be. If the user didn't supply
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// this command line option then a value of 2 will be used.
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int compression_level = get_option(parser,"l",2);
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// make sure one of the c or d options was given
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if (!parser.option("c") && !parser.option("d"))
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{
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cout << "Error in command line:\n You must specify either the c option or the d option.\n";
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cout << "\nTry the -h option for more information." << endl;
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return 0;
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}
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string in_file;
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string out_file;
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// check if the user told us the input file and if they did then
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// get the file name
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if (parser.option("in"))
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{
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in_file = parser.option("in").argument();
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}
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else
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{
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cout << "Error in command line:\n You must specify an input file.\n";
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cout << "\nTry the -h option for more information." << endl;
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return 0;
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}
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// check if the user told us the output file and if they did then
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// get the file name
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if (parser.option("out"))
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{
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out_file = parser.option("out").argument();
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}
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else
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{
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cout << "Error in command line:\n You must specify an output file.\n";
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cout << "\nTry the -h option for more information." << endl;
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return 0;
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}
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// open the files we will be reading from and writing to
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ifstream fin(in_file.c_str(),ios::binary);
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ofstream fout(out_file.c_str(),ios::binary);
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// make sure the files opened correctly
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if (!fin)
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{
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cout << "Error opening file " << in_file << ".\n";
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return 0;
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}
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if (!fout)
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{
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cout << "Error creating file " << out_file << ".\n";
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return 0;
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}
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// now perform the actual compression or decompression.
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if (parser.option("c"))
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{
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// save the compression level to the output file
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serialize(compression_level, fout);
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switch (compression_level)
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{
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case 1:
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{
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cs1 compressor;
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compressor.compress(fin,fout);
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}break;
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case 2:
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{
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cs2 compressor;
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compressor.compress(fin,fout);
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}break;
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case 3:
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{
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cs3 compressor;
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compressor.compress(fin,fout);
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}break;
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}
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}
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else
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{
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// obtain the compression level from the input file
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deserialize(compression_level, fin);
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switch (compression_level)
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{
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case 1:
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{
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cs1 compressor;
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compressor.decompress(fin,fout);
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}break;
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case 2:
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{
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cs2 compressor;
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compressor.decompress(fin,fout);
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}break;
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case 3:
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{
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cs3 compressor;
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compressor.decompress(fin,fout);
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}break;
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default:
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{
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cout << "Error in compressed file, invalid compression level" << endl;
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}break;
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}
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}
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}
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catch (exception& e)
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{
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// Note that this will catch any cmd_line_parse_error exceptions and print
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// the default message.
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cout << e.what() << endl;
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}
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}
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