#define BUILD_ASSERT_OR_ZERO(cond) \
(sizeof(char [1 - 2*!(cond)]) - 1)
-#if defined(__GNUC__) && (__GNUC__ >= 3)
-# if GIT_GNUC_PREREQ(3, 1)
+#if GIT_GNUC_PREREQ(3, 1)
/* &arr[0] degrades to a pointer: a different type from an array */
# define BARF_UNLESS_AN_ARRAY(arr) \
BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
__typeof__(&(arr)[0])))
-# else
-# define BARF_UNLESS_AN_ARRAY(arr) 0
-# endif
+#else
+# define BARF_UNLESS_AN_ARRAY(arr) 0
#endif
/*
* ARRAY_SIZE - get the number of elements in a visible array
#define unsigned_add_overflows(a, b) \
((b) > maximum_unsigned_value_of_type(a) - (a))
+/*
+ * Returns true if the multiplication of "a" and "b" will
+ * overflow. The types of "a" and "b" must match and must be unsigned.
+ * Note that this macro evaluates "a" twice!
+ */
+#define unsigned_mult_overflows(a, b) \
+ ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
+
#ifdef __GNUC__
#define TYPEOF(x) (__typeof__(x))
#else
return 0;
}
+/*
+ * Like skip_prefix, but promises never to read past "len" bytes of the input
+ * buffer, and returns the remaining number of bytes in "out" via "outlen".
+ */
+static inline int skip_prefix_mem(const char *buf, size_t len,
+ const char *prefix,
+ const char **out, size_t *outlen)
+{
+ size_t prefix_len = strlen(prefix);
+ if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
+ *out = buf + prefix_len;
+ *outlen = len - prefix_len;
+ return 1;
+ }
+ return 0;
+}
+
/*
* If buf ends with suffix, return 1 and subtract the length of the suffix
* from *len. Otherwise, return 0 and leave *len untouched.
typedef void (*try_to_free_t)(size_t);
extern try_to_free_t set_try_to_free_routine(try_to_free_t);
+static inline size_t st_add(size_t a, size_t b)
+{
+ if (unsigned_add_overflows(a, b))
+ die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
+ (uintmax_t)a, (uintmax_t)b);
+ return a + b;
+}
+#define st_add3(a,b,c) st_add((a),st_add((b),(c)))
+#define st_add4(a,b,c,d) st_add((a),st_add3((b),(c),(d)))
+
+static inline size_t st_mult(size_t a, size_t b)
+{
+ if (unsigned_mult_overflows(a, b))
+ die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
+ (uintmax_t)a, (uintmax_t)b);
+ return a * b;
+}
+
+static inline size_t st_sub(size_t a, size_t b)
+{
+ if (a < b)
+ die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
+ (uintmax_t)a, (uintmax_t)b);
+ return a - b;
+}
+
#ifdef HAVE_ALLOCA_H
# include <alloca.h>
# define xalloca(size) (alloca(size))
extern void *xrealloc(void *ptr, size_t size);
extern void *xcalloc(size_t nmemb, size_t size);
extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
+extern void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
extern ssize_t xread(int fd, void *buf, size_t len);
extern ssize_t xwrite(int fd, const void *buf, size_t len);
extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);