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#include <LibCore/CArgsParser.h>
#include <stdio.h>
#include <sys/stat.h>
#include <unistd.h>
enum TruncateOperation {
OP_Set,
OP_Grow,
OP_Shrink,
};
int main(int argc, char** argv)
{
CArgsParser args_parser("truncate");
args_parser.add_arg("s", "size", "Resize the target file to (or by) this size. Prefix with + or - to expand or shrink the file, or a bare number to set the size exactly.");
args_parser.add_arg("r", "reference", "Resize the target file to match the size of this one.");
args_parser.add_required_single_value("file");
CArgsParserResult args = args_parser.parse(argc, argv);
if (!args.is_present("s") && !args.is_present("r")) {
args_parser.print_usage();
return -1;
}
if (args.is_present("s") && args.is_present("r")) {
args_parser.print_usage();
return -1;
}
auto op = OP_Set;
int size = 0;
if (args.is_present("s")) {
auto str = args.get("s");
switch (str[0]) {
case '+':
op = OP_Grow;
str = str.substring(1, str.length() - 1);
break;
case '-':
op = OP_Shrink;
str = str.substring(1, str.length() - 1);
break;
}
bool ok;
size = str.to_int(ok);
if (!ok) {
args_parser.print_usage();
return -1;
}
}
if (args.is_present("r")) {
struct stat st;
int rc = stat(args.get("r").characters(), &st);
if (rc < 0) {
perror("stat");
return -1;
}
op = OP_Set;
size = st.st_size;
}
auto name = args.get_single_values()[0];
int fd = open(name.characters(), O_CREAT, 0666);
if (fd < 0) {
perror("open");
return -1;
}
struct stat st;
if (fstat(fd, &st) < 0) {
perror("fstat");
return -1;
}
switch (op) {
case OP_Set:
break;
case OP_Grow:
size = st.st_size + size;
break;
case OP_Shrink:
size = st.st_size - size;
break;
}
if (ftruncate(fd, size) < 0) {
perror("ftruncate");
return -1;
}
if (close(fd) < 0) {
perror("close");
return -1;
}
return 0;
}
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