pajjilykk/CS-LABS
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

working kirill's UNTESTED NEWLINE

Browse Source
This commit is contained in:
pajjilykk
2025-10-04 19:31:50 +07:00
parent 875c54c6f2
commit 1c2ba31179
5 changed files with 102 additions and 84 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
others/kirill`s/lab1/compile.sh
View File

@@ -1 +0,0 @@
g++ task18.cpp -o task18

11
others/kirill`s/lab1/file.in
View File

@@ -1,11 +0,0 @@
abcdef
abcdefg
abcdefghij
abc def
x
12
123
(three spaces)
abc
ab cs s dds
\tabcde\tf

2
others/kirill`s/lab1/in.txt Normal file
View File

@@ -0,0 +1,2 @@
123456
123456

169
others/kirill`s/lab1/task18.cpp
View File

@@ -1,96 +1,123 @@
#include <iostream> #include <unistd.h>
#include <fstream>
#include <string>
#include <sys/stat.h> #include <sys/stat.h>
#include <cstdlib> #include <fcntl.h>
#include <cerrno> #include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
static bool file_exists(const std::string &path) { #define RBUFSZ 4096
struct stat st{}; #define WBUFSZ 4096
return ::stat(path.c_str(), &st) == 0;
static void die_perror(const char *what, const char *path, int exit_code) {
int saved = errno;
char msg[512];
if (path) {
snprintf(msg, sizeof(msg), "%s: %s: %s\n", what, path, strerror(saved));
} else {
snprintf(msg, sizeof(msg), "%s: %s\n", what, strerror(saved));
}
(void) write(STDERR_FILENO, msg, strlen(msg));
_exit(exit_code);
} }
static std::string make_out_name(const std::string &in) { static long long parse_ll(const char *s) {
std::size_t pos = in.find_last_of('.'); char *end = NULL;
if (pos == std::string::npos) return in + ".out";
return in.substr(0, pos) + ".out";
}
static bool parse_nonneg_ll(const char *s, long long &out) {
if (!s || *s == '\0') return false;
char *end = nullptr;
errno = 0; errno = 0;
long long v = std::strtoll(s, &end, 10); long long v = strtoll(s, &end, 10);
if (errno != 0 || end == s || *end != '\0') return false; if (errno != 0 || end == s || *end != '\0' || v < 0) {
if (v < 0) return false; errno = EINVAL;
out = v; return -1;
return true; }
return v;
} }
int main(int argc, char *argv[]) { int main(int argc, char *argv[]) {
if (argc != 3) { if (argc != 4) {
std::cerr << "Usage: " << argv[0] << " input_file replace_count\n"; const char *usage =
"Usage: lab1_var_thirds_line <input.txt> <output.txt> <max_replacements>\n"
"Replace every third byte in each line with a space; counter resets after each newline.\n";
(void) write(STDERR_FILENO, usage, strlen(usage));
return -1; return -1;
} }
std::string in_path = argv[1]; const char *in_path = argv[1];
long long target = 0; const char *out_path = argv[2];
if (!parse_nonneg_ll(argv[2], target)) { long long cap = parse_ll(argv[3]);
std::cerr << "Usage: " << argv[0] << " input_file replace_count\n"; if (cap < 0) die_perror("invalid max_replacements", argv[3], -1);
return -1;
}
if (!file_exists(in_path)) { int in_fd = open(in_path, O_RDONLY);
std::cerr << "Error: input file does not exist.\n"; if (in_fd < 0) die_perror("open input failed", in_path, -1);
return -1;
}
std::ifstream in(in_path); mode_t perms = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH; /* 0666 */
if (!in) { int out_fd = open(out_path, O_CREAT | O_WRONLY | O_TRUNC, perms);
std::cerr << "Error: cannot open input file.\n"; if (out_fd < 0) die_perror("open output failed", out_path, -1);
return -1;
}
std::string out_path = make_out_name(in_path); char rbuf[RBUFSZ];
std::ofstream out(out_path); char wbuf[WBUFSZ];
if (!out) { size_t wlen = 0;
std::cerr << "Error: cannot create output file.\n";
return -1;
}
long long replacements = 0; long long total = 0;
std::string line; long long col = 0; /* position in current line starting from 1 */
int replacing_enabled = 1;
while (std::getline(in, line)) { for (;;) {
if (!line.empty() && replacements < target) { ssize_t n = read(in_fd, rbuf, sizeof(rbuf));
for (std::size_t idx = 0; idx < line.size() && replacements < target; ++idx) { if (n > 0) {
std::size_t pos1 = idx + 1; for (ssize_t i = 0; i < n; i++) {
if ((pos1 % 3) == 0) { unsigned char c = (unsigned char) rbuf[i];
if (line[idx] != ' ') {
line[idx] = ' '; if (c == '\n') {
++replacements; /* newline is written as-is and resets counter */
if (wlen == sizeof(wbuf)) {
ssize_t wrote = write(out_fd, wbuf, wlen);
if (wrote < 0 || (size_t) wrote != wlen) die_perror("write failed", out_path, -1);
wlen = 0;
}
wbuf[wlen++] = '\n';
col = 0;
continue;
}
col++; /* advance within the current line */
unsigned char outc = c;
if (replacing_enabled && (col % 3 == 0)) {
if (total < cap) {
outc = ' ';
total++;
if (total == cap) replacing_enabled = 0;
} else {
replacing_enabled = 0;
} }
} }
if (wlen == sizeof(wbuf)) {
ssize_t wrote = write(out_fd, wbuf, wlen);
if (wrote < 0 || (size_t) wrote != wlen) die_perror("write failed", out_path, -1);
wlen = 0;
}
wbuf[wlen++] = (char) outc;
} }
} } else if (n == 0) {
out << line; if (wlen > 0) {
if (!in.eof()) out << '\n'; ssize_t wrote = write(out_fd, wbuf, wlen);
if (!out) { if (wrote < 0 || (size_t) wrote != wlen) die_perror("write failed", out_path, -1);
std::cerr << "Error: write error.\n"; wlen = 0;
return -1; }
break;
} else {
die_perror("read failed", in_path, -1);
} }
} }
if (!in.eof() && in.fail()) { if (close(in_fd) < 0) die_perror("close input failed", in_path, -1);
std::cerr << "Error: read error.\n"; if (close(out_fd) < 0) die_perror("close output failed", out_path, -1);
return -1;
}
if (replacements != target) { char res[64];
std::cerr << "Error: could not perform exactly requested replacements.\n"; int m = snprintf(res, sizeof(res), "%lld\n", total);
return -1; if (m > 0) (void) write(STDOUT_FILENO, res, (size_t) m);
}
std::cout << replacements << std::endl; int exit_code = (int) (total & 0xFF);
return 0; return exit_code;
} }

3
others/vlad`s/lab1/in.txt
View File

@@ -1 +1,2 @@
aaaaabababbabababaaabbbbabababbbaabbaabbabb aaaaaa
aaaaaa