Add str2int() and str2double() helper functions

Don't silently ignore incorrect parameters.

1 files changed, 51 insertions, 0 deletions

diff --git a/include/common.h b/include/common.h
index fec3721..216f01c 100644
--- a/include/common.h
+++ b/include/common.h
@@ -12,4 +12,55 @@
  */
 void bail_out(const char* msg);
 
+/**
+ * Convert the given argument to an integer; set the flag if it fails.
+ * @param arg String to convert to integer (must not be NULL).
+ * @param failure_flag pointer to flag that will be set if conversion failed (may be NULL).
+ * @return integer value of arg
+ */
+int str2int(const char* arg, int *failure_flag);
+
+/**
+ * Convert the given argument to a double; set the flag if it fails.
+ * @param arg String to convert to double (must not be NULL).
+ * @param failure_flag pointer to flag that will be set if conversion failed (may be NULL).
+ * @return integer value of arg
+ */
+double str2double(const char* arg, int *failure_flag);
+
+
+/* the following macros assume that there is a no-return function called usage() */
+
+#define want_int_min(arg, min, msg) ({  \
+        int __val;                      \
+        int __fail;                     \
+        __val = str2int(arg, &__fail);  \
+        if (__fail || __val < min)      \
+                usage(msg);             \
+        __val;})
+
+#define want_double_min(arg, min, msg) ({       \
+        double __val;                           \
+        int __fail;                             \
+        __val = str2double(arg, &__fail);       \
+        if (__fail || __val < min)              \
+                usage(msg);                     \
+        __val;})
+
+#define want_non_negative_int(arg, name) \
+        want_int_min(arg, 0, "option " name " requires a non-negative integer argument")
+
+#define want_positive_int(arg, name) \
+        want_int_min(arg, 1, "option " name " requires a positive integer argument")
+
+#define want_non_negative_double(arg, name) \
+        want_double_min(arg, 0, "option " name " requires a non-negative argument")
+
+#define want_positive_double(arg, name) ({ \
+        double __val = want_double_min(arg, 0, "option " name " requires a positive argument"); \
+        if (!__val) \
+                usage("option " name " requires a positive argument"); \
+        __val; })
+
+
 #endif