handle encodings in printing output

Only really tested for LANG=en_US.UTF-8, but in theory this is
encoding-independent.

.vscode/launch.json

@@ -13,6 +13,7 @@
  "args": [],
  "env": {
  "TERM": "xterm-256color",
+ "LANG": "en_US.UTF-8",
  },
  "cwd": "${workspaceFolder}",
  "preLaunchTask": "make",

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes to this project will be documented in this file.
 ### Changed
 
 - Fixed potential crash in terminfo usage.
+- Use the C locale to better support non-ASCII in the output.
 
 ## [1.1] - 2019-11-24
 

src/main.c

@@ -1,5 +1,6 @@
 #include "config.h"
 #include <getopt.h>
+#include <locale.h>
 #include <ncurses.h>
 #include <readline/readline.h>
 #include <stdio.h>
@@ -54,25 +55,28 @@ void read_show_output(FILE *s, size_t *shown, size_t *total) {
  termput0("cd");
  char *line = NULL;
  size_t len = 0;
- for (;;) {
- ssize_t read = getline(&line, &len, s);
- if (read < 0)
- break;
+ ssize_t read;
+ wchar_t *wideline = (wchar_t*)calloc(COLS+1, sizeof(wchar_t));
+ while ((read = getline(&line, &len, s)) >= 0) {
+ *total += 1;
+ // if we haven't filled the screen yet, display this line.
  if (*shown < LINES - 2) {
- // sometimes newline, sometimes not, so chomp off any newline and
- // we'll add it ourselves for consistency.
- if (line[read - 1] == '\n')
+ // first, convert to a wchar_t string so we can easily count characters.
+ // limiting to COLS here truncates # of chars to the screen width.
+ size_t nchars = abort_ltz(mbstowcs(wideline, line, COLS));
+ // then, convert back to a byte string for display.
+ read = wcstombs(line, wideline, read);
+ // sometimes newline, sometimes not, so chomp off any newline
+ // and we'll add it ourselves for consistency.
+ if (read > 0 && line[read - 1] == '\n') {
  read -= 1;
- // truncate lines that are wider than the screen.
- if (read > COLS)
- read = COLS;
+ }
  printf("%.*s\n", (int)read, line);
  *shown += 1;
  }
- *total += 1;
  }
- if (line)
-  free(line);
+ free(line);
+ free(wideline);
 }
 
 int read_command(const char *command, size_t *shown, size_t *total) {
@@ -174,6 +178,7 @@ void version() {
 int main(int argc, char *const *argv) {
  if (argc)
  program_name = argv[0];
+ char *locale = setlocale(LC_ALL, "");
  int c;
  while ((c = getopt_long(argc, argv, "hv", long_options, NULL)) != -1) {
  switch (c) {