Add a simple macro calculating the size needed to store the string
representation of an integer type (both signed and unsigned) together
with the terminating NUL-character.
Suggested-by: Michael Conrad <mcon...@intellitree.com>
Signed-off-by: Bartosz Golaszewski <bartekg...@gmail.com>
---
include/libbb.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/include/libbb.h b/include/libbb.h
index 64e8490..826804a 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -298,6 +298,23 @@ struct BUG_off_t_size_is_misdetected {
#define BIT(nr) (1UL << (nr))
+/*
+ * Calculate the buffer size needed to hold the string representation of the
+ * given integer type.
+ *
+ * We're using 2.4 sizeof-to-buffer-size ratio and add one byte to round the
+ * result up, one byte for the terminating NUL-character and another one for
+ * the potential '-' character for signed types. This results in the following
+ * buffer lengths for common integer types.
+ *
+ * sizeof(type) calculated bufsize actual bufsize needed
+ * 1 5 5
+ * 2 7 7
+ * 4 12 12
+ * 8 22 21
+ */
+#define INT_BUF_MAX(type) (sizeof(type) * 24 / 10 + 3)
+
/* Macros for min/max. */
#ifndef MIN
#define MIN(a,b) (((a)<(b))?(a):(b))
--
2.1.4
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