libcdecl: Avoid snprintf for integer conversions.

[cdecl99.git] / src / output.c

diff --git a/src/output.c b/src/output.c
index 8c2cd0b6b1b4e9b9fe2d2934f6538d95abdb4be4..047fc64ed087138d0d0ceb305485a54d88b0c89d 100644 (file)
--- a/src/output.c
+++ b/src/output.c
@@ -1,27 +1,122 @@
+/*
+ *  Helper functions for outputting text.
+ *  Copyright © 2011, 2021, 2023 Nick Bowler
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <config.h>
 #include <stdio.h>
-#include "output.h"
+#include <assert.h>
 
-size_t cdecl__advance_(char **buf, size_t *n, size_t amount)
+#include "cdecl.h"
+#include "cdecl-internal.h"
+
+#include "parse.h"
+#include "specstr.h"
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+size_t cdecl__advance(struct output_state *dst, size_t amount)
 {
-       if (amount >= *n) {
-               *n   = 0;
-               *buf = 0;
-       } else {
-               *buf += amount;
-               *n   -= amount;
-       }
+       size_t x = MIN(amount, dst->dstlen);
+
+       dst->dst    += x;
+       dst->dstlen -= x;
+       dst->accum  += amount;
 
        return amount;
 }
 
-size_t cdecl__advance(char **buf, size_t *n, size_t amount)
+size_t cdecl__strlcpy(char *dst, const char *src, size_t dstlen)
 {
-       size_t ret, rc;
+       if (dst)
+               snprintf(dst, dstlen, "%s", src);
+       return strlen(src);
+}
 
-       if (!amount)
-               return 0;
+size_t cdecl__emit(struct output_state *dst, const char *src)
+{
+       size_t rc = cdecl__strlcpy(dst->dst, src, dst->dstlen);
+       return cdecl__advance(dst, rc);
+}
+
+/*
+ * 31 decimal digits is enough for values up to 2^102 - 1.
+ * 63 decimal digits is enough for values up to 2^209 - 1.
+ *
+ * We can't portably write numbers this large in preprocessor conditionals,
+ * but since the maximum values of unsigned integer types are always one
+ * less than a power of two, we can use a sequence of small shifts to infer
+ * the bounds.
+ *
+ * All known implementations have 64-bit uintmax_t.  Leave some headroom
+ * to support a possible future implementatons with 128-bit uintmax_t.
+ */
+enum {
+#if (UINTMAX_MAX >> 27 >> 27 >> 26 >> 26) == 0
+       MAX_UINT_DIGITS = 31
+#elif (UINTMAX_MAX >> 27 >> 26 >> 26 >> 26 >> 26 >> 26 >> 26 >> 26) == 0
+       MAX_UINT_DIGITS = 63
+#else
+#      error UINTMAX_MAX is too large, please report a bug.
+#endif
+};
+
+size_t cdecl__emit_uint(struct output_state *dst, uintmax_t val)
+{
+       char buf[MAX_UINT_DIGITS + 1], *p = &buf[sizeof buf];
+
+       *(--p) = 0;
+       while (val > 0) {
+               *(--p) = '0' + val % 10;
+               val /= 10;
+       }
+
+       return cdecl__emit(dst, p);
+}
+
+static void explain_spec(struct output_state *dst, struct cdecl_declspec *s)
+{
+       size_t rc;
+
+       rc = cdecl__emit(dst, spec_string(s->type));
+       if (s->ident) {
+               cdecl__emit(dst, " " + !rc);
+               cdecl__emit(dst, s->ident);
+       }
+}
+
+/*
+ * Render a list of declaration specifiers.  Only the declaration specifiers
+ * listed in mask, which is the bitwise OR of the desired specifier kinds, are
+ * printed.
+ */
+const char *cdecl__emit_specs(struct output_state *dst,
+                              struct cdecl_declspec *s,
+                              unsigned mask)
+{
+       const char *sep = " ";
+       int empty = 1;
+
+       for (; s; s = s->next) {
+               if (!(s->type & mask))
+                       continue;
+
+               cdecl__emit(dst, sep + empty);
+               explain_spec(dst, s);
+               empty = 0;
+       }
 
-       ret = cdecl__advance_(buf, n, amount);
-       rc = snprintf(*buf, *n, " ");
-       return ret + cdecl__advance_(buf, n, rc);
+       return sep + empty;
 }