1 #define EXPAND_2_INNER_CASES(i, x, y) INNER_CASE(i, x, y); INNER_CASE(i + 1, x, y);
2 #define EXPAND_4_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i + 2, x, y)
3 #define EXPAND_8_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i + 4, x, y)
4 #define EXPAND_16_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i + 8, x, y)
5 #define EXPAND_32_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i + 16, x, y)
6 #define EXPAND_64_INNER_CASES(i, x, y) EXPAND_32_INNER_CASES(i, x, y) EXPAND_32_INNER_CASES(i + 32, x, y)
7
8 #define EXPAND_2_OUTER_CASES(i, x, y) OUTER_CASE(i, x, y); OUTER_CASE(i + 1, x, y);
9 #define EXPAND_4_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i + 2, x, y)
10 #define EXPAND_8_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i + 4, x, y)
11 #define EXPAND_16_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i + 8, x, y)
12 #define EXPAND_32_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i + 16, x, y)
13 #define EXPAND_64_OUTER_CASES(i, x, y) EXPAND_32_OUTER_CASES(i, x, y) EXPAND_32_OUTER_CASES(i + 32, x, y)
14
15 // Rather than a single monstrous fan-out, this fans out in smaller increments,
16 // but to a similar size.
cfg_nested_switch(int x)17 unsigned cfg_nested_switch(int x) {
18 unsigned y = 0;
19 while (x > 0) {
20 switch (x) {
21 #define INNER_CASE(i, x, y) \
22 case i: { int case_var = 3*x + i; y += case_var - 1; break; }
23 #define OUTER_CASE(i, x, y) \
24 case i: { \
25 int case_var = y >> 8; \
26 switch (case_var) { \
27 EXPAND_64_INNER_CASES(0, x, y); \
28 } \
29 break; \
30 }
31 EXPAND_64_OUTER_CASES(0, x, y);
32 }
33 --x;
34 }
35 return y;
36 }
37