Add hnel

1 files changed, 98 insertions, 0 deletions

diff --git a/home/.bin/hnel.c b/home/.bin/hnel.c
new file mode 100755
index 00000000..0e270a5c
--- /dev/null
+++ b/home/.bin/hnel.c
@@ -0,0 +1,98 @@
+#if 0
+exec cc -Wall -Wextra -pedantic $@ -lutil -o $(dirname $0)/hnel $0
+#endif
+
+// Wrapper for preserving HJKL in Tarmak layouts.
+
+#include <err.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <termios.h>
+#include <unistd.h>
+
+#if defined __FreeBSD__
+#include <libutil.h>
+#elif defined __linux__
+#include <pty.h>
+#else
+#include <util.h>
+#endif
+
+static ssize_t writeAll(int fd, const char *buf, size_t len) {
+    ssize_t writeLen;
+    while (0 < (writeLen = write(fd, buf, len))) {
+        buf += writeLen;
+        len -= writeLen;
+    }
+    return writeLen;
+}
+
+static struct termios saveTerm;
+
+static void restoreTerm(void) {
+    tcsetattr(STDERR_FILENO, TCSADRAIN, &saveTerm);
+}
+
+int main(int argc, char *argv[]) {
+    if (argc < 2) return EX_USAGE;
+
+    char table[256] = {0};
+    table['n'] = 'j'; table['N'] = 'J'; table[CTRL('N')] = CTRL('J');
+    table['e'] = 'k'; table['E'] = 'K'; table[CTRL('E')] = CTRL('K');
+    table['j'] = 'e'; table['J'] = 'E'; table[CTRL('J')] = CTRL('E');
+    table['k'] = 'n'; table['K'] = 'N'; table[CTRL('K')] = CTRL('N');
+
+    int master;
+    pid_t pid = forkpty(&master, NULL, NULL, NULL);
+    if (pid < 0) err(EX_OSERR, "forkpty");
+
+    if (!pid) {
+        execvp(argv[1], argv + 1);
+        err(EX_OSERR, "%s", argv[1]);
+    }
+
+    int error = tcgetattr(STDERR_FILENO, &saveTerm);
+    if (error) err(EX_IOERR, "tcgetattr");
+    atexit(restoreTerm);
+
+    struct termios raw;
+    cfmakeraw(&raw);
+    error = tcsetattr(STDERR_FILENO, TCSADRAIN, &raw);
+    if (error) err(EX_IOERR, "tcsetattr");
+
+    struct pollfd fds[2] = {
+        { .fd = STDIN_FILENO, .events = POLLIN },
+        { .fd = master, .events = POLLIN },
+    };
+
+    char buf[4096];
+    ssize_t len;
+    while (0 < poll(fds, 2, -1)) {
+        if (fds[0].revents) {
+            len = read(STDIN_FILENO, buf, sizeof(buf));
+            if (len < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
+
+            if (len == 1) {
+                unsigned char c = buf[0];
+                if (table[c]) buf[0] = table[c];
+            }
+
+            len = writeAll(master, buf, len);
+            if (len < 0) err(EX_IOERR, "write(%d)", master);
+        }
+
+        if (fds[1].revents) {
+            len = read(master, buf, sizeof(buf));
+            if (len < 0) err(EX_IOERR, "read(%d)", master);
+            len = writeAll(STDOUT_FILENO, buf, len);
+            if (len < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
+        }
+
+        int status;
+        pid_t dead = waitpid(pid, &status, WNOHANG);
+        if (dead < 0) err(EX_OSERR, "waitpid(%d)", pid);
+        if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
+    }
+    err(EX_IOERR, "poll");
+}