Try to approximate if file is printeable

include/file.h

@@ -5,6 +5,7 @@
 struct filedata {
   int lc;
   size_t len;
+  int binary;
   char *buf;
 };
 

include/util.h

@@ -4,7 +4,7 @@
 
 void die(const char *message);
 
-char *formatBytes(size_t bytes, float *rounded);
+char *formatbytes(size_t bytes, float *rounded);
 
 int intlen(size_t i);
 #endif

src/lib/file.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "file.h"
 #include "util.h"
@@ -9,9 +10,9 @@ struct filedata readfile(FILE *fp) {
 
   f.lc = 0;
   f.len = 0;
+  f.binary = 0;
 
   size_t bufsize = 4;
-
   f.buf = malloc(bufsize);
   if (f.buf == NULL)
     die("malloc");
@@ -37,5 +38,19 @@ struct filedata readfile(FILE *fp) {
     f.buf[f.len++] = c;
   }
 
+  // guess if printable
+  // from https://github.com/sharkdp/content_inspector/blob/master/src/lib.rs
+  int testlen = 64;
+  char *testbuf[testlen];
+  memcpy(testbuf, f.buf, testlen);
+
+  char *result = memchr(testbuf, 0x00, testlen);
+
+  if (result) {
+    f.binary = 1;
+  } else {
+    f.binary = 0;
+  }
+
   return f;
 }

src/lib/util.c

@@ -7,7 +7,7 @@ void die(const char *message) {
   exit(1);
 }
 
-char *formatBytes(size_t bytes, float *rounded) {
+char *formatbytes(size_t bytes, float *rounded) {
   char *SIZES[] = {"bytes", "kB", "MB", "GB"};
 
   size_t size = bytes;

src/main.c

@@ -12,14 +12,15 @@
 #define GREY "\x1b[90m"
 #define RESET "\x1b[0m"
 
-void run(FILE *fp, char *filename) {
+void run(FILE *fp, char *filename, int tty) {
-  int tty = isatty(STDOUT_FILENO);
-
   struct filedata f;
   f = readfile(fp);
 
-  if (tty)
+  if (tty) {
-    fprintf(stderr, "\r%s%s%s\r\n", INVERT_T, basename(filename), UINVERT_T);
+    char *addon = f.binary ? " <binary>" : "";
+    fprintf(stderr, "\n%s%s%s%s\r\n", INVERT_T, basename(filename), addon,
+            UINVERT_T);
+  }
 
   int lcpad = intlen(f.lc);
 
@@ -29,11 +30,13 @@ void run(FILE *fp, char *filename) {
   for (size_t i = 0; i < f.len; i++) {
     c = f.buf[i];
 
-    if (tty && (pc == '\n' || i == 0)) {
+    if (tty && !f.binary && (pc == '\n' || i == 0)) {
       f.lc++;
 
       int padlen = lcpad - intlen(f.lc);
       char padding[padlen];
+
+      if (padlen)
         memset(padding, ' ', padlen);
 
       fprintf(stderr, "\r%s%s%d:%s ", GREY, padlen > 0 ? padding : "", f.lc,
@@ -44,11 +47,13 @@ void run(FILE *fp, char *filename) {
     printf("%c", c);
   }
 
+  fflush(stdout); // prevent timing inconsistencies between stdout and stderr
+
   if (tty) {
     float rounded;
-    char *format = formatBytes(f.len, &rounded);
+    char *format = formatbytes(f.len, &rounded);
 
-    fprintf(stderr, "\r%s%.2f %s%s\r\n", INVERT_T, rounded, format, UINVERT_T);
+    fprintf(stderr, "\n%s%.2f %s%s\r\n", INVERT_T, rounded, format, UINVERT_T);
   }
 }
 
@@ -58,7 +63,9 @@ int main(int argc, char *argv[]) {
       FILE *fp = fopen(argv[i], "rb");
       if (fp == NULL)
         die(argv[i]);
-      run(fp, argv[i]);
+
+      int tty = isatty(STDOUT_FILENO);
+      run(fp, argv[i], tty);
       fclose(fp);
 
       if (i + 1 != argc) {
@@ -66,7 +73,7 @@ int main(int argc, char *argv[]) {
       }
     }
   } else {
-    run(stdin, "stdin"); // for piped-input or repl-like behavior
+    run(stdin, "stdin", 1); // for piped-input or repl-like behavior
   }
 
   return 0;