1 files changed, 93 insertions, 0 deletions
diff --git a/toys/other/fmt.c b/toys/other/fmt.c
new file mode 100644
index 00000000..764fe2b7
--- /dev/null
+++ b/toys/other/fmt.c
@@ -0,0 +1,93 @@
+/* fmt.c - Text formatter
+ *
+ * Copyright 2017 The Android Open Source Project
+ *
+ * No standard.
+ *
+ * Only counts space and tab for indent level (eats other low ascii chars,
+ * treats all UTF8 chars as non-whitespace), preserves indentation but squashes
+ * together runs of whitespace. No header/footer logic, no end-of-sentence
+ * double-space, preserves initial tab/space mix when indenting new lines.
+
+USE_FMT(NEWTOY(fmt, "w#<0=75", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LOCALE))
+
+config FMT
+  bool "fmt"
+  default y
+  help
+    usage: fmt [-w WIDTH] [FILE...]
+
+    Reformat input to wordwrap at a given line length, preserving existing
+    indentation level, writing to stdout.
+
+    -w WIDTH	maximum characters per line (default 75)
+*/
+
+#define FOR_fmt
+#include "toys.h"
+
+GLOBALS(
+  int width;
+
+  int level, pos;
+)
+
+static void newline(void)
+{
+  if (TT.pos) xputc('\n');
+  TT.pos = 0;
+}
+
+// Process lines of input, with (0,0) flush between files
+static void fmt_line(char **pline, long len)
+{
+  char *line;
+  int idx, indent, count;
+
+  // Flush line on EOF
+  if (!pline) return newline();
+
+  // Measure indentation
+  for (line = *pline, idx = count = 0; isspace(line[idx]); idx++) {
+    if (line[idx]=='\t') count += 8-(count&7);
+    else if (line[idx]==' ') count++;
+  }
+  indent = idx;
+
+  // Blank lines (even with same indentation) flush line
+  if (idx==len) {
+    xputc('\n');
+    TT.level = 0;
+
+    return newline();
+  }
+
+  // Did indentation change?
+  if (count!=TT.level) newline();
+  TT.level = count;
+
+  // Loop through words
+  while (idx<len) {
+    char *word = line+idx;
+
+    // Measure this word (unicode width) and end
+    while (idx<len && !isspace(line[idx])) idx++;
+    line[idx++] = 0;
+    count = utf8len(word);
+    if (TT.pos+count+!!TT.pos>=TT.width) newline();
+
+    // When indenting a new line, preserve tab/space mixture of input
+    if (!TT.pos) {
+      TT.pos = TT.level;
+      if (indent) printf("%.*s", indent, line);
+    } else count++;
+    printf(" %s"+!(TT.pos!=TT.level), word);
+    TT.pos += count;
+    while (isspace(line[idx])) idx++;
+  }
+}
+
+void fmt_main(void)
+{
+  loopfiles_lines(toys.optargs, fmt_line);
+}