libcdecl: reduce snprintf reliance for error reporting.

[cdecl99.git] / src / error.c

diff --git a/src/error.c b/src/error.c
index cf4411e0e89b8da7dfbe82fcbda7ddf0c18c871b..758f58e63c50d4159195b08189c10cd6467e06c2 100644 (file)
--- a/src/error.c
+++ b/src/error.c
@@ -134,6 +134,35 @@ void cdecl__errmsg(unsigned msg)
        set_err(msg, &state->err);
 }
 
+/*
+ * In the NLS-disabled case, all format strings are of the form
+ *
+ *   "blah blah %s"
+ *
+ * so we exploit this to implement a simple snprintf workalike using the
+ * libcdecl output helpers directly.
+ *
+ * In the NLS-enabled case, we have to use snprintf as format strings may
+ * be translated.  GNU libintl ensures a suitable version is available.
+ */
+static size_t
+fmt_err(struct err_state *state, const char *fmt, const char *arg)
+{
+#if ENABLE_NLS
+       snprintf(state->str, state->nstr, fmt, arg);
+       return strlen(fmt) + strlen(arg);
+#else
+       struct output_state dst = { state->str, state->nstr };
+       size_t rc;
+
+       rc = cdecl__strlcpy(dst.dst, fmt, dst.dstlen);
+       cdecl__advance(&dst, rc-2);
+       cdecl__emit(&dst, arg);
+
+       return dst.accum;
+#endif
+}
+
 /*
  * Sets the library error to code; fmt is a printf-style string that may use
  * up to one %s directive, to refer to arg.
@@ -141,16 +170,18 @@ void cdecl__errmsg(unsigned msg)
 void cdecl__err(unsigned code, const char *fmt, const char *arg)
 {
        struct err_state *state;
-       int rc, try = 0;
+       unsigned try = 0;
+       size_t rc;
 
        state = get_err_state();
        if (!state)
                return;
 
 retry:
-       rc = snprintf(state->str, state->nstr, fmt, arg);
-       if (rc > 0 && rc >= state->nstr) {
+       rc = fmt_err(state, fmt, arg);
+       if (rc >= state->nstr) {
                assert(try++ == 0 && rc < SIZE_MAX / 4);
+
                state = alloc_err_state(state, (size_t)(rc+1u) * 3 / 2);
                if (!state)
                        return;