bit-test.rar_The Test

#include <glib.h> #if defined(__GNUC__) && (__GNUC__ >= 4) # define TEST_BUILTINS 1 #else # define TEST_BUILTINS 0 #endif #if TEST_BUILTINS static gint builtin_bit_nth_lsf1 (gulong mask, gint nth_bit) { if (nth_bit >= 0) { if (G_LIKELY (nth_bit < GLIB_SIZEOF_LONG * 8 - 1)) mask &= -(1UL<<(nth_bit+1)); else mask = 0; } return __builtin_ffsl(mask) - 1; } static gint builtin_bit_nth_lsf2 (gulong mask, gint nth_bit) { if (nth_bit >= 0) { if (G_LIKELY (nth_bit < GLIB_SIZEOF_LONG * 8 - 1)) mask &= -(1UL<<(nth_bit+1)); else mask = 0; } return mask ? __builtin_ctzl(mask) : -1; } static gint builtin_bit_nth_msf (gulong mask, gint nth_bit) { if (nth_bit >= 0 && nth_bit < GLIB_SIZEOF_LONG * 8) mask &= (1UL<<nth_bit)-1; return mask ? GLIB_SIZEOF_LONG * 8 - 1 - __builtin_clzl(mask) : -1; } static guint builtin_bit_storage (gulong number) { return number ? GLIB_SIZEOF_LONG * 8 - __builtin_clzl(number) : 1; } #endif static gint naive_bit_nth_lsf (gulong mask, gint nth_bit) { if (G_UNLIKELY (nth_bit < -1)) nth_bit = -1; while (nth_bit < ((GLIB_SIZEOF_LONG * 8) - 1)) { nth_bit++; if (mask & (1UL << nth_bit)) return nth_bit; } return -1; } static gint naive_bit_nth_msf (gulong mask, gint nth_bit) { if (nth_bit < 0 || G_UNLIKELY (nth_bit > GLIB_SIZEOF_LONG * 8)) nth_bit = GLIB_SIZEOF_LONG * 8; while (nth_bit > 0) { nth_bit--; if (mask & (1UL << nth_bit)) return nth_bit; } return -1; } static guint naive_bit_storage (gulong number) { register guint n_bits = 0; do { n_bits++; number >>= 1; } while (number); return n_bits; } #define TEST(f1, f2, i) \ if (f1 (i) != f2 (i)) { \ g_error (G_STRINGIFY (f1) " (%lu) = %d; " \ G_STRINGIFY (f2) " (%lu) = %d; ", \ i, f1 (i), \ i, f2 (i)); \ return 1; \ } #define TEST2(f1, f2, i, n) \ if (f1 (i, n) != f2 (i, n)) { \ g_error (G_STRINGIFY (f1) " (%lu, %d) = %d; " \ G_STRINGIFY (f2) " (%lu, %d) = %d; ", \ i, n, f1 (i, n), \ i, n, f2 (i, n)); \ return 1; \ } int main (void) { gulong i; gint nth_bit; /* we loop like this: 0, -1, 1, -2, 2, -3, 3, ... */ for (i = 0; (glong)i < 1500 ; i = -(i+((glong)i>=0))) { #if TEST_BUILTINS TEST (naive_bit_storage, builtin_bit_storage, i); #endif TEST (naive_bit_storage, g_bit_storage, i); for (nth_bit = -3; nth_bit <= 2 + GLIB_SIZEOF_LONG * 8; nth_bit++) { #if TEST_BUILTINS TEST2 (naive_bit_nth_lsf, builtin_bit_nth_lsf1, i, nth_bit); TEST2 (naive_bit_nth_lsf, builtin_bit_nth_lsf2, i, nth_bit); #endif TEST2 (naive_bit_nth_lsf, g_bit_nth_lsf, i, nth_bit); #if TEST_BUILTINS TEST2 (naive_bit_nth_msf, builtin_bit_nth_msf, i, nth_bit); #endif TEST2 (naive_bit_nth_msf, g_bit_nth_msf, i, nth_bit); } } return 0; }