Do not output useless NULs at the end of files.

Author: larsbrinkhoff

libword/aa-word.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2018 Lars Brinkhoff <lars@nocrew.org>
+/* Copyright (C) 2018, 2022 Lars Brinkhoff <lars@nocrew.org>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -28,6 +28,8 @@
 
 #include "libword.h"
 
+static word_t output = -1;
+
 static inline int
 get_byte (FILE *f)
 {
@@ -59,12 +61,38 @@ get_aa_word (FILE *f)
 static void
 write_aa_word (FILE *f, word_t word)
 {
-  fputc ((word >> 29) & 0177, f);
-  fputc ((word >> 22) & 0177, f);
-  fputc ((word >> 15) & 0177, f);
-  fputc ((word >>  8) & 0177, f);
-  fputc (((word >> 1) & 0177) +
-	 ((word << 7) & 0200), f);
+  if (output != -1)
+    {
+      fputc ((output >> 29) & 0177, f);
+      fputc ((output >> 22) & 0177, f);
+      fputc ((output >> 15) & 0177, f);
+      fputc ((output >>  8) & 0177, f);
+      fputc (((output >> 1) & 0177) +
+	     ((output << 7) & 0200), f);
+    }
+
+  output = word;
+}
+
+static void
+flush_aa_word (FILE *f)
+{
+  int i, c;
+  if (output == -1)
+    return;
+  fputc ((output >> 29) & 0177, f);
+  for (i = 0; i < 4; i++)
+    {
+      output &= 03777777777LL;
+      if (output == 0)
+	break;
+      c = (output >> 22) & 0177;
+      if (i == 3 && (output & 010000000LL) != 0)
+	c |= 0200;
+      fputc (c, f);
+      output <<= 7;
+    }
+  output = -1;
 }
 
 struct word_format aa_word_format = {
@@ -73,5 +101,5 @@ struct word_format aa_word_format = {
   NULL,
   by_five_octets,
   write_aa_word,
-  NULL
+  flush_aa_word
 };

libword/its-word.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2013 Lars Brinkhoff <lars@nocrew.org>
+/* Copyright (C) 2013, 2022 Lars Brinkhoff <lars@nocrew.org>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -18,6 +18,9 @@
 #include "libword.h"
 
 static int leftover, there_is_some_leftover = 0;
+static word_t output = -1;
+
+static void write_its_word (FILE *f, word_t word);
 
 #define WORDMASK	(0777777777777LL)
 #define SIGNBIT		(0400000000000LL)
@@ -158,6 +161,7 @@ static void
 rewind_its_word (FILE *f)
 {
   there_is_some_leftover = 0;
+  output = -1;
   rewind (f);
 }
 
@@ -171,7 +175,7 @@ fputc2 (int c1, int c2, FILE *f)
 static int previous_octet = -1;
 
 static void
-flush_its_word (FILE *f)
+end_word (FILE *f)
 {
   if (previous_octet == 015)
     fputc (0356, f);
@@ -183,7 +187,7 @@ flush_its_word (FILE *f)
 static void
 binary_word (FILE *f, word_t word)
 {
-  flush_its_word (f);
+  end_word (f);
 
   fputc (((word >> 32) &  017) + 0360, f);
   fputc (((word >> 24) & 0377), f);
@@ -193,7 +197,7 @@ binary_word (FILE *f, word_t word)
 }
 
 static void
-ascii_word (FILE *f, word_t word)
+ascii_word (FILE *f, word_t word, int n)
 {
   char c, octets[5];
   int i;
@@ -204,7 +208,7 @@ ascii_word (FILE *f, word_t word)
   octets[3] = (word >>  8) & 0177;
   octets[4] = (word >>  1) & 0177;
 
-  for (i = 0; i < 5; i++)
+  for (i = 0; i < n; i++)
     {
       c = octets[i];
 
@@ -252,13 +256,45 @@ ascii_word (FILE *f, word_t word)
     }
 }
 
+static int
+characters (word_t word)
+{
+  int i, n;
+  n = 0;
+  for (i = 0; i < 5; i++)
+    {
+      if (word == 0)
+	break;
+      word = (word << 7) & 0777777777777LL;
+      n++;
+    }
+  return n;
+}
+
 static void
-write_its_word (FILE *f, word_t word)
+flush_its_word (FILE *f)
 {
-  if (word & 1)
-    binary_word (f, word);
+  end_word (f);
+  if (output == -1)
+    return;
+  if (output & 1)
+    binary_word (f, output);
   else
-    ascii_word (f, word);
+    ascii_word (f, output, characters (output));
+  output = -1;
+}
+
+static void
+write_its_word (FILE *f, word_t word)
+{
+  if (output != -1)
+    {
+      if (output & 1)
+	binary_word (f, output);
+      else
+	ascii_word (f, output, 5);
+    }
+  output = word;
 }
 
 struct word_format its_word_format = {