@@@ tvec doc wip

[mLib] / utils / gprintf.c

diff --git a/utils/gprintf.c b/utils/gprintf.c
index f527186373599d53b271ff4a12fa666610052996..602698cdbbd096d1a4f1fedfd0df4d466060038b 100644 (file)
--- a/utils/gprintf.c
+++ b/utils/gprintf.c
@@ -373,7 +373,7 @@ int vgprintf(const struct gprintf_ops *ops, void *out,
        break;
       default:
        fprintf(stderr,
-               "FATAL dstr_vputf: unknown format specifier `%c'\n", p[-1]);
+               "FATAL vgprintf: unknown format specifier `%c'\n", p[-1]);
        abort();
     }
 
@@ -416,9 +416,13 @@ int vgprintf(const struct gprintf_ops *ops, void *out,
 
     if (fs->fmt == fmt_unset) {
       switch (fs->ch) {
-       case 0: break;
-       case '%': ops->putch(out, '%'); break;
-       default: abort();
+       case 0:
+         break;
+       case '%':
+         if (ops->putch(out, '%')) return (-1);
+         tot++; break;
+       default:
+         abort();
       }
       continue;
     }
@@ -497,7 +501,7 @@ int vgprintf(const struct gprintf_ops *ops, void *out,
 #else
 #  define MSG "<no float support>"
        if (ops->putm(out, MSG, sizeof(MSG) - 1)) return (-1);
-       continue;
+       tot += sizeof(MSG) - 1; continue;
 #  undef MSG
 #endif
       case 's':
@@ -563,6 +567,54 @@ int gprintf(const struct gprintf_ops *ops, void *out, const char *p, ...)
   return (n);
 }
 
+/*----- Utilities ---------------------------------------------------------*/
+
+/* --- @gprintf_memputf@ --- *
+ *
+ * Arguments:  @char **buf_inout@ = address of output buffer pointer
+ *             @size_t *sz_inout@ = address of buffer size
+ *             @size_t maxsz@ = buffer size needed for this operation
+ *             @const char *p@ = pointer to format string
+ *             @va_list *ap@ = captured format-arguments tail
+ *
+ * Returns:    The formatted length.
+ *
+ * Use:                Generic utility for mostly implementing the @nputf@ output
+ *             function, if you don't have a better option.
+ *
+ *             On entry, @*buf_inout@ should be null or a buffer pointer,
+ *             with @*sz_inout@ either zero or the buffer's size,
+ *             respectively.  On exit, @*buf_input@ and @*sz_inout@ will be
+ *             updated, if necessary, to describe a sufficiently large
+ *             buffer, and the formatted string will have been written to
+ *             the buffer.
+ *
+ *             When the buffer is no longer required, free it using @xfree@.
+ */
+
+size_t gprintf_memputf(char **buf_inout, size_t *sz_inout,
+                   size_t maxsz, const char *p, va_list ap)
+{
+  char *buf = *buf_inout;
+  size_t sz = *sz_inout;
+  int n;
+
+  if (sz <= maxsz) {
+    if (!sz) sz = 32;
+    while (sz <= maxsz) sz *= 2;
+    if (buf) xfree(buf);
+    buf = xmalloc(sz); *buf_inout = buf; *sz_inout = sz;
+  }
+
+#ifdef HAVE_SNPRINTF
+  n = vsnprintf(buf, maxsz + 1, p, ap);
+#else
+  n = vsprintf(buf, p, ap);
+#endif
+  assert(0 <= n && n <= maxsz);
+  return (n);
+}
+
 /*----- Standard printers -------------------------------------------------*/
 
 static int file_putch(void *out, int ch)