PATCH: typeset -L/R/Z padding with multibyte characters

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

Here's a small one of the remaining multibyte tasks:  fix the typeset
padding flags to use multibyte characters.  This uses the character
count, not the character's screen widths.

Index: Doc/Zsh/builtins.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/builtins.yo,v
retrieving revision 1.88
diff -u -r1.88 builtins.yo
--- Doc/Zsh/builtins.yo	10 Nov 2006 09:59:27 -0000	1.88
+++ Doc/Zsh/builtins.yo	13 Dec 2006 22:24:57 -0000
@@ -1405,6 +1405,15 @@
 the first assignment.  In the case of numeric parameters, the length of the
 complete value assigned to the parameter is used to determine the width,
 not the value that would be output.
+
+The width is the count of characters, which may be multibyte characters
+if the tt(MULTIBYTE) option is in effect.  Note that the screen
+width of the character is not taken into account; if this is required,
+use padding with parameter expansion flags
+tt(${+LPAR()ml)var(...)tt(RPAR())var(...)tt(}) as described in
+`Parameter Expansion Flags' in
+ifzman(zmanref(zshexpn))ifnzman(noderef(Parameter Expansion)).
+
 When the parameter is expanded, it is filled on the right with
 blanks or truncated if necessary to fit the field.
 Note truncation can lead to unexpected results with numeric parameters.
Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.69
diff -u -r1.69 subst.c
--- Src/subst.c	3 Dec 2006 21:07:18 -0000	1.69
+++ Src/subst.c	13 Dec 2006 22:24:58 -0000
@@ -761,8 +761,8 @@
 /*
  * Pad the string str, returning a result from the heap (or str itself,
  * if it didn't need padding).  If str is too large, it will be truncated.
- * Calculations are in terms of width if MULTIBYTE is in effect, else
- * characters.
+ * Calculations are in terms of width if MULTIBYTE is in effect and
+ * multi_width is non-zero, else characters.
  *
  * prenum and postnum are the width to which the string needs padding
  * on the left and right.
@@ -2211,7 +2211,7 @@
 		val = getstrvalue(v);
 		fwidth = v->pm->width ? v->pm->width : (int)strlen(val);
 		switch (v->pm->node.flags & (PM_LEFT | PM_RIGHT_B | PM_RIGHT_Z)) {
-		    char *t;
+		    char *t, *tend;
 		    unsigned int t0;
 
 		case PM_LEFT:
@@ -2223,21 +2223,39 @@
 		    else
 			while (iblank(*t))
 			    t++;
-		    val = (char *) hcalloc(fwidth + 1);
-		    val[fwidth] = '\0';
-		    if ((t0 = strlen(t)) > fwidth)
-			t0 = fwidth;
-		    memset(val, ' ', fwidth);
-		    strncpy(val, t, t0);
+		    MB_METACHARINIT();
+		    for (tend = t, t0 = 0; t0 < fwidth && *tend; t0++)
+			tend += MB_METACHARLEN(tend);
+		    /*
+		     * t0 is the number of characters from t used,
+		     * hence (fwidth - t0) is the number of padding
+		     * characters.  fwidth is a misnomer: we use
+		     * character counts, not character widths.
+		     *
+		     * (tend - t) is the number of bytes we need
+		     * to get fwidth characters or the entire string;
+		     * the characters may be multiple bytes.
+		     */
+		    fwidth -= t0; /* padding chars remaining */
+		    t0 = tend - t; /* bytes to copy from string */
+		    val = (char *) hcalloc(t0 + fwidth + 1);
+		    memcpy(val, t, t0);
+		    if (fwidth)
+			memset(val + t0, ' ', fwidth);
+		    val[t0 + fwidth] = '\0';
+		    copied = 1;
 		    break;
 		case PM_RIGHT_B:
 		case PM_RIGHT_Z:
 		case PM_RIGHT_Z | PM_RIGHT_B:
 		    {
 			int zero = 1;
+			/* Calculate length in possibly multibyte chars */
+			int charlen = MB_METASTRLEN(val);
 
-			if (strlen(val) < fwidth) {
+			if (charlen < fwidth) {
 			    char *valprefend = val;
+			    int preflen;
 			    if (v->pm->node.flags & PM_RIGHT_Z) {
 				/*
 				 * This is a documented feature: when deciding
@@ -2277,33 +2295,31 @@
 				} else if (!idigit(*t))
 				    zero = 0;
 			    }
-			    t = (char *) hcalloc(fwidth + 1);
-			    memset(t, (((v->pm->node.flags & PM_RIGHT_B) || !zero) ?
-				       ' ' : '0'), fwidth);
-			    /*
-			     * How can the following trigger?  We
-			     * haven't altered val or fwidth since
-			     * the last time we tested this.
-			     */
-			    if ((t0 = strlen(val)) > fwidth)
-				t0 = fwidth;
+			    /* number of characters needed for padding */
+			    fwidth -= charlen;
+			    /* bytes from original string */
+			    t0 = strlen(val);
+			    t = (char *) hcalloc(fwidth + t0 + 1);
+			    /* prefix guaranteed to be single byte chars */
+			    preflen = valprefend - val;
+			    memset(t + preflen, 
+				   (((v->pm->node.flags & PM_RIGHT_B)
+				     || !zero) ?       ' ' : '0'), fwidth);
 			    /*
 			     * Copy - or 0x or base# before any padding
 			     * zeroes.
 			     */
-			    if (zero && val != valprefend) {
-				int preflen = valprefend - val;
+			    if (preflen)
 				memcpy(t, val, preflen);
-				strcpy(t + (fwidth - t0) + preflen,
-				       valprefend);
-			    } else
-				strcpy(t + (fwidth - t0), val);
+			    memcpy(t + preflen + fwidth,
+				   valprefend, t0 - preflen);
+			    t[fwidth + t0] = '\0';
 			    val = t;
+			    copied = 1;
 			} else {
-			    t = (char *) hcalloc(fwidth + 1);
-			    t[fwidth] = '\0';
-			    strncpy(t, val + strlen(val) - fwidth, fwidth);
-			    val = t;
+			    /* Need to skip (charlen - fwidth) chars */
+			    for (t0 = charlen - fwidth; t0; t0--)
+				val += MB_METACHARLEN(val);
 			}
 		    }
 		    break;

-- 
Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/