maint: add more control flags to mbsalign

* gl/lib/mbsalign.h: Add MBA_UNIBYTE_ONLY (to allow
faster processing).  Also add MBA_NO_LEFT_PAD, MBA_NO_RIGHT_PAD
to give greater control of padding, useful with the first
or last fields on a line.
* gl/lib/mbsalign.c (mbsalign): Implement the new flags.
* gl/tests/test-mbsalign.c (main): Test combinations
of the new flags.

1 files changed, 22 insertions, 9 deletions

diff --git a/gl/lib/mbsalign.h b/gl/lib/mbsalign.h
index e9340f926..25d529e48 100644
--- a/gl/lib/mbsalign.h
+++ b/gl/lib/mbsalign.h
@@ -21,20 +21,33 @@ typedef enum { MBS_ALIGN_LEFT, MBS_ALIGN_RIGHT, MBS_ALIGN_CENTER } mbs_align_t;
 enum {
   /* Use unibyte mode for invalid multibyte strings
      or when heap memory is exhausted.  */
-  MBA_UNIBYTE_FALLBACK = 0x0001
+  MBA_UNIBYTE_FALLBACK = 0x0001,
+
+  /* As an optimization, don't do multibyte processing
+     when we know no multibyte characters are present.  */
+  MBA_UNIBYTE_ONLY = 0x0002,
+
+  /* Don't add leading padding.  */
+  MBA_NO_LEFT_PAD = 0x0004,
+
+  /* Don't add trailing padding.  */
+  MBA_NO_RIGHT_PAD = 0x0008
 
 #if 0 /* Other possible options.  */
-  /* Skip invalid multibyte chars rather than failing  */
-  MBA_IGNORE_INVALID   = 0x0002,
+  /* Skip invalid multibyte chars rather than failing.  */
+  MBA_IGNORE_INVALID
+
+  /* Align multibyte strings using "figure space" (\u2007).  */
+  MBA_USE_FIGURE_SPACE
 
-  /* Align multibyte strings using "figure space" (\u2007)  */
-  MBA_USE_FIGURE_SPACE = 0x0004,
+  /* Don't truncate.  */
+  MBA_NO_TRUNCATE
 
-  /* Don't add any padding  */
-  MBA_TRUNCATE_ONLY    = 0x0008,
+  /* Ensure no leading whitepsace.  */
+  MBA_LSTRIP
 
-  /* Don't truncate  */
-  MBA_PAD_ONLY         = 0x0010,
+  /* Ensure no trailing whitepsace.  */
+  MBA_RSTRIP
 #endif
 };