]> git.cameronkatri.com Git - mandoc.git/blobdiff - html.c
Have mandoc-db accumulate manual page descriptions (`Nd' in -mdoc parlance)
[mandoc.git] / html.c
diff --git a/html.c b/html.c
index f096720f4c032ece3db7ba9f272a5ff403800d4d..812a1847338295b11886df3465dc557b0ee915d1 100644 (file)
--- a/html.c
+++ b/html.c
@@ -1,6 +1,7 @@
-/*     $Id: html.c,v 1.74 2009/10/30 18:53:08 kristaps Exp $ */
+/*     $Id: html.c,v 1.132 2011/04/09 15:29:40 kristaps Exp $ */
 /*
- * Copyright (c) 2008, 2009 Kristaps Dzonsons <kristaps@kth.se>
+ * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2011 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <sys/types.h>
 
 #include <assert.h>
 #include <ctype.h>
-#include <stdio.h>
 #include <stdarg.h>
+#include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
+#include "mandoc.h"
 #include "out.h"
-#include "chars.h"
 #include "html.h"
 #include "main.h"
 
-#define        UNCONST(a)      ((void *)(uintptr_t)(const void *)(a))
-
-#define        DOCTYPE         "-//W3C//DTD HTML 4.01//EN"
-#define        DTD             "http://www.w3.org/TR/html4/strict.dtd"
-
 struct htmldata {
        const char       *name;
        int               flags;
 #define        HTML_CLRLINE     (1 << 0)
 #define        HTML_NOSTACK     (1 << 1)
+#define        HTML_AUTOCLOSE   (1 << 2) /* Tag has auto-closure. */
 };
 
 static const struct htmldata htmltags[TAG_MAX] = {
        {"html",        HTML_CLRLINE}, /* TAG_HTML */
        {"head",        HTML_CLRLINE}, /* TAG_HEAD */
        {"body",        HTML_CLRLINE}, /* TAG_BODY */
-       {"meta",        HTML_CLRLINE | HTML_NOSTACK}, /* TAG_META */
+       {"meta",        HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_META */
        {"title",       HTML_CLRLINE}, /* TAG_TITLE */
        {"div",         HTML_CLRLINE}, /* TAG_DIV */
        {"h1",          0}, /* TAG_H1 */
        {"h2",          0}, /* TAG_H2 */
-       {"p",           HTML_CLRLINE}, /* TAG_P */
        {"span",        0}, /* TAG_SPAN */
-       {"link",        HTML_CLRLINE | HTML_NOSTACK}, /* TAG_LINK */
-       {"br",          HTML_CLRLINE | HTML_NOSTACK}, /* TAG_LINK */
+       {"link",        HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_LINK */
+       {"br",          HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_BR */
        {"a",           0}, /* TAG_A */
        {"table",       HTML_CLRLINE}, /* TAG_TABLE */
-       {"col",         HTML_CLRLINE | HTML_NOSTACK}, /* TAG_COL */
+       {"tbody",       HTML_CLRLINE}, /* TAG_TBODY */
+       {"col",         HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_COL */
        {"tr",          HTML_CLRLINE}, /* TAG_TR */
        {"td",          HTML_CLRLINE}, /* TAG_TD */
        {"li",          HTML_CLRLINE}, /* TAG_LI */
        {"ul",          HTML_CLRLINE}, /* TAG_UL */
        {"ol",          HTML_CLRLINE}, /* TAG_OL */
-       {"base",        HTML_CLRLINE | HTML_NOSTACK}, /* TAG_BASE */
+       {"dl",          HTML_CLRLINE}, /* TAG_DL */
+       {"dt",          HTML_CLRLINE}, /* TAG_DT */
+       {"dd",          HTML_CLRLINE}, /* TAG_DD */
+       {"blockquote",  HTML_CLRLINE}, /* TAG_BLOCKQUOTE */
+       {"p",           HTML_CLRLINE | HTML_NOSTACK | HTML_AUTOCLOSE}, /* TAG_P */
+       {"pre",         HTML_CLRLINE }, /* TAG_PRE */
+       {"b",           0 }, /* TAG_B */
+       {"i",           0 }, /* TAG_I */
+       {"code",        0 }, /* TAG_CODE */
+       {"small",       0 }, /* TAG_SMALL */
 };
 
-static const char       *const htmlattrs[ATTR_MAX] = {
-       "http-equiv",
-       "content",
-       "name",
-       "rel",
-       "href",
-       "type",
-       "media",
-       "class",
-       "style",
-       "width",
-       "valign",
-       "target",
-       "id",
-       "summary",
+static const char      *const htmlattrs[ATTR_MAX] = {
+       "http-equiv", /* ATTR_HTTPEQUIV */
+       "content", /* ATTR_CONTENT */
+       "name", /* ATTR_NAME */
+       "rel", /* ATTR_REL */
+       "href", /* ATTR_HREF */
+       "type", /* ATTR_TYPE */
+       "media", /* ATTR_MEDIA */
+       "class", /* ATTR_CLASS */
+       "style", /* ATTR_STYLE */
+       "width", /* ATTR_WIDTH */
+       "id", /* ATTR_ID */
+       "summary", /* ATTR_SUMMARY */
+       "align", /* ATTR_ALIGN */
+       "colspan", /* ATTR_COLSPAN */
 };
 
-#ifdef __linux__
-extern int               getsubopt(char **, char * const *, char **);
-#endif
-
-void *
-html_alloc(char *outopts)
+static void              print_num(struct html *, const char *, size_t);
+static void              print_spec(struct html *, const char *, size_t);
+static void              print_res(struct html *, const char *, size_t);
+static void              print_ctag(struct html *, enum htmltag);
+static void              print_doctype(struct html *);
+static void              print_xmltype(struct html *);
+static int               print_encode(struct html *, const char *, int);
+static void              print_metaf(struct html *, enum mandoc_esc);
+static void              print_attr(struct html *, 
+                               const char *, const char *);
+static void             *ml_alloc(char *, enum htmltype);
+
+
+static void *
+ml_alloc(char *outopts, enum htmltype type)
 {
        struct html     *h;
        const char      *toks[4];
@@ -99,14 +118,10 @@ html_alloc(char *outopts)
        toks[2] = "includes";
        toks[3] = NULL;
 
-       h = calloc(1, sizeof(struct html));
-       if (NULL == h) {
-               fprintf(stderr, "memory exhausted\n");
-               exit(EXIT_FAILURE);
-       }
+       h = mandoc_calloc(1, sizeof(struct html));
 
+       h->type = type;
        h->tags.head = NULL;
-       h->ords.head = NULL;
        h->symtab = chars_init(CHARS_HTML);
 
        while (outopts && *outopts)
@@ -127,21 +142,30 @@ html_alloc(char *outopts)
        return(h);
 }
 
+void *
+html_alloc(char *outopts)
+{
+
+       return(ml_alloc(outopts, HTML_HTML_4_01_STRICT));
+}
+
+
+void *
+xhtml_alloc(char *outopts)
+{
+
+       return(ml_alloc(outopts, HTML_XHTML_1_0_STRICT));
+}
+
 
 void
 html_free(void *p)
 {
        struct tag      *tag;
-       struct ord      *ord;
        struct html     *h;
 
        h = (struct html *)p;
 
-       while ((ord = h->ords.head) != NULL) { 
-               h->ords.head = ord->next;
-               free(ord);
-       }
-
        while ((tag = h->tags.head) != NULL) {
                h->tags.head = tag->next;       
                free(tag);
@@ -184,163 +208,175 @@ print_gen_head(struct html *h)
        }
 }
 
+/* ARGSUSED */
+static void
+print_num(struct html *h, const char *p, size_t len)
+{
+       const char      *rhs;
+
+       rhs = chars_num2char(p, len);
+       if (rhs)
+               putchar((int)*rhs);
+}
 
 static void
-print_spec(struct html *h, const char *p, int len)
+print_spec(struct html *h, const char *p, size_t len)
 {
+       int              cp;
        const char      *rhs;
-       int              i;
        size_t           sz;
 
-       rhs = chars_a2ascii(h->symtab, p, (size_t)len, &sz);
-
-       if (NULL == rhs) 
+       if ((cp = chars_spec2cp(h->symtab, p, len)) > 0) {
+               printf("&#%d;", cp);
+               return;
+       } else if (-1 == cp && 1 == len) {
+               fwrite(p, 1, len, stdout);
                return;
-       for (i = 0; i < (int)sz; i++) 
-               putchar(rhs[i]);
+       } else if (-1 == cp)
+               return;
+
+       if (NULL != (rhs = chars_spec2str(h->symtab, p, len, &sz)))
+               fwrite(rhs, 1, sz, stdout);
 }
 
 
 static void
-print_res(struct html *h, const char *p, int len)
+print_res(struct html *h, const char *p, size_t len)
 {
+       int              cp;
        const char      *rhs;
-       int              i;
        size_t           sz;
 
-       rhs = chars_a2res(h->symtab, p, (size_t)len, &sz);
-
-       if (NULL == rhs)
+       if ((cp = chars_res2cp(h->symtab, p, len)) > 0) {
+               printf("&#%d;", cp);
+               return;
+       } else if (-1 == cp)
                return;
-       for (i = 0; i < (int)sz; i++) 
-               putchar(rhs[i]);
+
+       if (NULL != (rhs = chars_res2str(h->symtab, p, len, &sz)))
+               fwrite(rhs, 1, sz, stdout);
 }
 
 
 static void
-print_escape(struct html *h, const char **p)
+print_metaf(struct html *h, enum mandoc_esc deco)
 {
-       int              j, type;
-       const char      *wp;
+       enum htmlfont    font;
 
-       wp = *p;
-       type = 1;
+       switch (deco) {
+       case (ESCAPE_FONTPREV):
+               font = h->metal;
+               break;
+       case (ESCAPE_FONTITALIC):
+               font = HTMLFONT_ITALIC;
+               break;
+       case (ESCAPE_FONTBOLD):
+               font = HTMLFONT_BOLD;
+               break;
+       case (ESCAPE_FONTROMAN):
+               font = HTMLFONT_NONE;
+               break;
+       default:
+               abort();
+               /* NOTREACHED */
+       }
 
-       if (0 == *(++wp)) {
-               *p = wp;
-               return;
+       if (h->metaf) {
+               print_tagq(h, h->metaf);
+               h->metaf = NULL;
        }
 
-       if ('(' == *wp) {
-               wp++;
-               if (0 == *wp || 0 == *(wp + 1)) {
-                       *p = 0 == *wp ? wp : wp + 1;
-                       return;
-               }
+       h->metal = h->metac;
+       h->metac = font;
 
-               print_spec(h, wp, 2);
-               *p = ++wp;
-               return;
+       if (HTMLFONT_NONE != font)
+               h->metaf = HTMLFONT_BOLD == font ?
+                       print_otag(h, TAG_B, 0, NULL) :
+                       print_otag(h, TAG_I, 0, NULL);
+}
 
-       } else if ('*' == *wp) {
-               if (0 == *(++wp)) {
-                       *p = wp;
-                       return;
-               }
 
-               switch (*wp) {
-               case ('('):
-                       wp++;
-                       if (0 == *wp || 0 == *(wp + 1)) {
-                               *p = 0 == *wp ? wp : wp + 1;
-                               return;
-                       }
+static int
+print_encode(struct html *h, const char *p, int norecurse)
+{
+       size_t           sz;
+       int              len, nospace;
+       const char      *seq;
+       enum mandoc_esc  esc;
+       static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
 
-                       print_res(h, wp, 2);
-                       *p = ++wp;
-                       return;
-               case ('['):
-                       type = 0;
+       nospace = 0;
+
+       while ('\0' != *p) {
+               sz = strcspn(p, rejs);
+
+               fwrite(p, 1, sz, stdout);
+               p += (int)sz;
+
+               if ('\0' == *p)
                        break;
+
+               switch (*p++) {
+               case ('<'):
+                       printf("&lt;");
+                       continue;
+               case ('>'):
+                       printf("&gt;");
+                       continue;
+               case ('&'):
+                       printf("&amp;");
+                       continue;
+               case (ASCII_HYPH):
+                       putchar('-');
+                       continue;
                default:
-                       print_res(h, wp, 1);
-                       *p = wp;
-                       return;
-               }
-       
-       } else if ('f' == *wp) {
-               if (0 == *(++wp)) {
-                       *p = wp;
-                       return;
+                       break;
                }
 
-               switch (*wp) {
-               case ('B'):
-                       /* TODO */
+               esc = mandoc_escape(&p, &seq, &len);
+               if (ESCAPE_ERROR == esc)
+                       break;
+
+               switch (esc) {
+               case (ESCAPE_NUMBERED):
+                       print_num(h, seq, len);
+                       break;
+               case (ESCAPE_PREDEF):
+                       print_res(h, seq, len);
                        break;
-               case ('I'):
-                       /* TODO */
+               case (ESCAPE_SPECIAL):
+                       print_spec(h, seq, len);
                        break;
-               case ('P'):
+               case (ESCAPE_FONTPREV):
                        /* FALLTHROUGH */
-               case ('R'):
-                       /* TODO */
+               case (ESCAPE_FONTBOLD):
+                       /* FALLTHROUGH */
+               case (ESCAPE_FONTITALIC):
+                       /* FALLTHROUGH */
+               case (ESCAPE_FONTROMAN):
+                       if (norecurse)
+                               break;
+                       print_metaf(h, esc);
+                       break;
+               case (ESCAPE_NOSPACE):
+                       if ('\0' == *p)
+                               nospace = 1;
                        break;
                default:
                        break;
                }
-
-               *p = wp;
-               return;
-
-       } else if ('[' != *wp) {
-               print_spec(h, wp, 1);
-               *p = wp;
-               return;
-       }
-
-       wp++;
-       for (j = 0; *wp && ']' != *wp; wp++, j++)
-               /* Loop... */ ;
-
-       if (0 == *wp) {
-               *p = wp;
-               return;
        }
 
-       if (type)
-               print_spec(h, wp - j, j);
-       else
-               print_res(h, wp - j, j);
-
-       *p = wp;
+       return(nospace);
 }
 
 
 static void
-print_encode(struct html *h, const char *p)
+print_attr(struct html *h, const char *key, const char *val)
 {
-
-       for (; *p; p++) {
-               if ('\\' == *p) {
-                       print_escape(h, &p);
-                       continue;
-               }
-               switch (*p) {
-               case ('<'):
-                       printf("&lt;");
-                       break;
-               case ('>'):
-                       printf("&gt;");
-                       break;
-               case ('&'):
-                       printf("&amp;");
-                       break;
-               default:
-                       putchar(*p);
-                       break;
-               }
-       }
+       printf(" %s=\"", key);
+       (void)print_encode(h, val, 1);
+       putchar('\"');
 }
 
 
@@ -351,12 +387,10 @@ print_otag(struct html *h, enum htmltag tag,
        int              i;
        struct tag      *t;
 
+       /* Push this tags onto the stack of open scopes. */
+
        if ( ! (HTML_NOSTACK & htmltags[tag].flags)) {
-               t = malloc(sizeof(struct tag));
-               if (NULL == t) {
-                       fprintf(stderr, "memory exhausted\n");
-                       exit(EXIT_FAILURE);
-               }
+               t = mandoc_malloc(sizeof(struct tag));
                t->tag = tag;
                t->next = h->tags.head;
                h->tags.head = t;
@@ -364,29 +398,57 @@ print_otag(struct html *h, enum htmltag tag,
                t = NULL;
 
        if ( ! (HTML_NOSPACE & h->flags))
-               if ( ! (HTML_CLRLINE & htmltags[tag].flags))
-                       printf(" ");
+               if ( ! (HTML_CLRLINE & htmltags[tag].flags)) {
+                       /* Manage keeps! */
+                       if ( ! (HTML_KEEP & h->flags)) {
+                               if (HTML_PREKEEP & h->flags)
+                                       h->flags |= HTML_KEEP;
+                               putchar(' ');
+                       } else
+                               printf("&#160;");
+               }
+
+       if ( ! (h->flags & HTML_NONOSPACE))
+               h->flags &= ~HTML_NOSPACE;
+       else
+               h->flags |= HTML_NOSPACE;
+
+       /* Print out the tag name and attributes. */
 
        printf("<%s", htmltags[tag].name);
-       for (i = 0; i < sz; i++) {
-               printf(" %s=\"", htmlattrs[p[i].key]);
-               assert(p->val);
-               print_encode(h, p[i].val);
-               printf("\"");
+       for (i = 0; i < sz; i++)
+               print_attr(h, htmlattrs[p[i].key], p[i].val);
+
+       /* Add non-overridable attributes. */
+
+       if (TAG_HTML == tag && HTML_XHTML_1_0_STRICT == h->type) {
+               print_attr(h, "xmlns", "http://www.w3.org/1999/xhtml");
+               print_attr(h, "xml:lang", "en");
+               print_attr(h, "lang", "en");
        }
-       printf(">");
+
+       /* Accomodate for XML "well-formed" singleton escaping. */
+
+       if (HTML_AUTOCLOSE & htmltags[tag].flags)
+               switch (h->type) {
+               case (HTML_XHTML_1_0_STRICT):
+                       putchar('/');
+                       break;
+               default:
+                       break;
+               }
+
+       putchar('>');
 
        h->flags |= HTML_NOSPACE;
-       if (HTML_CLRLINE & htmltags[tag].flags)
-               h->flags |= HTML_NEWLINE;
-       else
-               h->flags &= ~HTML_NEWLINE;
+
+       if ((HTML_AUTOCLOSE | HTML_CLRLINE) & htmltags[tag].flags)
+               putchar('\n');
 
        return(t);
 }
 
 
-/* ARGSUSED */
 static void
 print_ctag(struct html *h, enum htmltag tag)
 {
@@ -394,73 +456,84 @@ print_ctag(struct html *h, enum htmltag tag)
        printf("</%s>", htmltags[tag].name);
        if (HTML_CLRLINE & htmltags[tag].flags) {
                h->flags |= HTML_NOSPACE;
-               h->flags |= HTML_NEWLINE;
-               printf("\n");
-       } else
-               h->flags &= ~HTML_NEWLINE;
+               putchar('\n');
+       } 
 }
 
 
-/* ARGSUSED */
 void
-print_gen_doctype(struct html *h)
+print_gen_decls(struct html *h)
 {
-       
-       printf("<!DOCTYPE HTML PUBLIC \"%s\" \"%s\">", DOCTYPE, DTD);
+
+       print_xmltype(h);
+       print_doctype(h);
+}
+
+
+static void
+print_xmltype(struct html *h)
+{
+
+       if (HTML_XHTML_1_0_STRICT == h->type)
+               puts("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
 }
 
 
+static void
+print_doctype(struct html *h)
+{
+       const char      *doctype;
+       const char      *dtd;
+       const char      *name;
+
+       switch (h->type) {
+       case (HTML_HTML_4_01_STRICT):
+               name = "HTML";
+               doctype = "-//W3C//DTD HTML 4.01//EN";
+               dtd = "http://www.w3.org/TR/html4/strict.dtd";
+               break;
+       default:
+               name = "html";
+               doctype = "-//W3C//DTD XHTML 1.0 Strict//EN";
+               dtd = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";
+               break;
+       }
+
+       printf("<!DOCTYPE %s PUBLIC \"%s\" \"%s\">\n", 
+                       name, doctype, dtd);
+}
+
 void
-print_text(struct html *h, const char *p)
+print_text(struct html *h, const char *word)
 {
 
-       if (*p && 0 == *(p + 1))
-               switch (*p) {
-               case('.'):
-                       /* FALLTHROUGH */
-               case(','):
-                       /* FALLTHROUGH */
-               case(';'):
-                       /* FALLTHROUGH */
-               case(':'):
-                       /* FALLTHROUGH */
-               case('?'):
-                       /* FALLTHROUGH */
-               case('!'):
-                       /* FALLTHROUGH */
-               case(')'):
-                       /* FALLTHROUGH */
-               case(']'):
-                       /* FALLTHROUGH */
-               case('}'):
-                       if ( ! (HTML_IGNDELIM & h->flags))
-                               h->flags |= HTML_NOSPACE;
-                       break;
-               default:
-                       break;
-               }
+       if ( ! (HTML_NOSPACE & h->flags)) {
+               /* Manage keeps! */
+               if ( ! (HTML_KEEP & h->flags)) {
+                       if (HTML_PREKEEP & h->flags)
+                               h->flags |= HTML_KEEP;
+                       putchar(' ');
+               } else
+                       printf("&#160;");
+       }
 
-       if ( ! (h->flags & HTML_NOSPACE))
-               printf(" ");
+       assert(NULL == h->metaf);
+       if (HTMLFONT_NONE != h->metac)
+               h->metaf = HTMLFONT_BOLD == h->metac ?
+                       print_otag(h, TAG_B, 0, NULL) :
+                       print_otag(h, TAG_I, 0, NULL);
 
-       h->flags &= ~HTML_NOSPACE;
-       h->flags &= ~HTML_NEWLINE;
+       assert(word);
+       if ( ! print_encode(h, word, 0))
+               if ( ! (h->flags & HTML_NONOSPACE))
+                       h->flags &= ~HTML_NOSPACE;
 
-       if (p)
-               print_encode(h, p);
+       if (h->metaf) {
+               print_tagq(h, h->metaf);
+               h->metaf = NULL;
+       }
 
-       if (*p && 0 == *(p + 1))
-               switch (*p) {
-               case('('):
-                       /* FALLTHROUGH */
-               case('['):
-                       /* FALLTHROUGH */
-               case('{'):
-                       h->flags |= HTML_NOSPACE;
-                       break;
-               default:
-                       break;
-               }
+       h->flags &= ~HTML_IGNDELIM;
 }
 
 
@@ -470,6 +543,14 @@ print_tagq(struct html *h, const struct tag *until)
        struct tag      *tag;
 
        while ((tag = h->tags.head) != NULL) {
+               /* 
+                * Remember to close out and nullify the current
+                * meta-font and table, if applicable.
+                */
+               if (tag == h->metaf)
+                       h->metaf = NULL;
+               if (tag == h->tblt)
+                       h->tblt = NULL;
                print_ctag(h, tag->tag);
                h->tags.head = tag->next;
                free(tag);
@@ -487,6 +568,14 @@ print_stagq(struct html *h, const struct tag *suntil)
        while ((tag = h->tags.head) != NULL) {
                if (suntil && tag == suntil)
                        return;
+               /* 
+                * Remember to close out and nullify the current
+                * meta-font and table, if applicable.
+                */
+               if (tag == h->metaf)
+                       h->metaf = NULL;
+               if (tag == h->tblt)
+                       h->tblt = NULL;
                print_ctag(h, tag->tag);
                h->tags.head = tag->next;
                free(tag);
@@ -643,11 +732,11 @@ bufcat_su(struct html *h, const char *p, const struct roffsu *su)
                break;
        }
 
-       if (su->pt)
-               buffmt(h, "%s: %f%s;", p, v, u);
-       else
-               /* LINTED */
-               buffmt(h, "%s: %d%s;", p, (int)v, u);
+       /* 
+        * XXX: the CSS spec isn't clear as to which types accept
+        * integer or real numbers, so we just make them all decimals.
+        */
+       buffmt(h, "%s: %.2f%s;", p, v, u);
 }
 
 
@@ -656,20 +745,24 @@ html_idcat(char *dst, const char *src, int sz)
 {
        int              ssz;
 
-       assert(sz);
+       assert(sz > 2);
 
        /* Cf. <http://www.w3.org/TR/html4/types.html#h-6.2>. */
 
-       for ( ; *dst != '\0' && sz; dst++, sz--)
-               /* Jump to end. */ ;
-
-       assert(sz > 2);
-
        /* We can't start with a number (bah). */
 
-       *dst++ = 'x';
-       *dst = '\0';
-       sz--;
+       if ('#' == *dst) {
+               dst++;
+               sz--;
+       }
+       if ('\0' == *dst) {
+               *dst++ = 'x';
+               *dst = '\0';
+               sz--;
+       }
+
+       for ( ; *dst != '\0' && sz; dst++, sz--)
+               /* Jump to end. */ ;
 
        for ( ; *src != '\0' && sz > 1; src++) {
                ssz = snprintf(dst, (size_t)sz, "%.2x", *src);