From 925ba68c3ca97b8d437f95f3b329b50f43238907 Mon Sep 17 00:00:00 2001
From: Shav Kinderlehrer <shav@trinket.icu>
Date: Fri, 9 Jun 2023 13:52:14 -0400
Subject: Add auto-pager

---
 src/lib/arg.c |  6 ++++--
 src/main.c    | 22 ++++++++++++++++------
 2 files changed, 20 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/lib/arg.c b/src/lib/arg.c
index 993f7fa..bb2928c 100644
--- a/src/lib/arg.c
+++ b/src/lib/arg.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdnoreturn.h>
+#include <sys/ioctl.h>
 #include <unistd.h>
 
 #include "arg.h"
@@ -24,9 +25,10 @@ void help(void) {
          "binary\n"
          "\t-r           print everything (headers, line numbers, etc.) to "
          "stdout (or equivalent)\n"
-         "\t-p           print file with the pager (uses less)\n"
+         "\t-p           disable or enable pager (uses less)\n"
          "\t-n <name>    manually set the name of the file shown in the title\n"
-         // "\t-e <program> NONFUNCTIONAL (will be added soon)  link extension to lat\n"
+         // "\t-e <program> NONFUNCTIONAL (will be added soon)  link extension
+         // to lat\n"
          "\t-V           show program version\n"
          "\t-h           display this help text\n\n");
   printf("environment:\n"
diff --git a/src/main.c b/src/main.c
index 5d4a097..23e59b8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/ioctl.h>
 #include <unistd.h>
 
 #include "arg.h"
@@ -52,10 +53,25 @@ void run(FILE *fp, char *filename, bool tty) {
   struct filedata f;
   f = readfile(fp, conf.isstdin);
 
+  // any/all processing to be done
+  // TODO: maybe multithread?
+  conf.process = (tty && !f.binary);
+  if (conf.process) { // file display processing
+    loadlines(&f);
+  }
+
   if (conf.extension != NULL) {
     // TODO
   }
 
+  struct winsize w;
+
+  if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) != -1 || w.ws_col != 0) {
+    if (w.ws_row <= f.lc + 5) {
+      conf.pager = !conf.pager;
+    }
+  }
+
   if (conf.pager) {
     st = popen("less", "w");
     err = st;
@@ -78,12 +94,6 @@ void run(FILE *fp, char *filename, bool tty) {
     printheadertop(filename, f.binary);
   }
 
-  // any/all processing to be done
-  conf.process = (tty && !f.binary);
-  if (conf.process) { // file display processing
-    loadlines(&f);
-  }
-
   if (conf.process) {
     int linecount = 1;
     for (int i = 0; i < f.lc; i++) {
-- 
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