njn | 3e88418 | 2003-04-15 13:03:23 +0000 | [diff] [blame] | 1 | #include <string.h> |
| 2 | #include <stdio.h> |
| 3 | |
| 4 | char b[50]; |
| 5 | |
| 6 | void reset_b(void) |
| 7 | { |
| 8 | int i; |
| 9 | |
| 10 | for (i = 0; i < 50; i++) |
| 11 | b[i] = '_'; |
| 12 | b[49] = '\0'; |
| 13 | } |
| 14 | |
| 15 | void reset_b2(void) |
| 16 | { |
| 17 | reset_b(); |
| 18 | strcpy(b, "ABCDEFG"); |
| 19 | } |
| 20 | |
| 21 | int main(void) |
| 22 | { |
| 23 | char x[100]; |
| 24 | char a[] = "abcdefghijklmnopqrstuvwxyz"; |
| 25 | int i; |
| 26 | |
| 27 | /* testing memcpy/strcpy overlap */ |
| 28 | |
| 29 | for (i = 0; i < 50; i++) { |
| 30 | x[i] = i+1; // don't put any zeroes in there |
| 31 | } |
| 32 | for (i = 50; i < 100; i++) { |
| 33 | // because of the errors, the strcpy's will overrun, so put some |
| 34 | // zeroes in the second half to stop them eventually |
| 35 | x[i] = 0; |
| 36 | |
| 37 | } |
| 38 | |
| 39 | memcpy(x+20, x, 20); // ok |
| 40 | memcpy(x+20, x, 21); // overlap |
| 41 | memcpy(x, x+20, 20); // ok |
| 42 | memcpy(x, x+20, 21); // overlap |
| 43 | |
| 44 | strncpy(x+20, x, 20); // ok |
| 45 | strncpy(x+20, x, 21); // overlap |
| 46 | strncpy(x, x+20, 20); // ok |
| 47 | strncpy(x, x+20, 21); // overlap |
| 48 | |
| 49 | x[39] = '\0'; |
| 50 | strcpy(x, x+20); // ok |
| 51 | |
| 52 | x[39] = 39; |
| 53 | x[40] = '\0'; |
| 54 | strcpy(x, x+20); // overlap |
| 55 | |
| 56 | x[19] = '\0'; |
| 57 | strcpy(x+20, x); // ok |
| 58 | |
| 59 | /* |
| 60 | x[19] = 19; |
| 61 | x[20] = '\0'; |
| 62 | strcpy(x+20, x); // overlap, but runs forever (or until it seg faults) |
| 63 | */ |
| 64 | |
| 65 | /* testing strcpy, strncpy() */ |
| 66 | |
| 67 | reset_b(); |
| 68 | printf("`%s'\n", b); |
| 69 | |
| 70 | strcpy(b, a); |
| 71 | printf("`%s'\n", b); |
| 72 | |
| 73 | reset_b(); |
| 74 | strncpy(b, a, 25); |
| 75 | printf("`%s'\n", b); |
| 76 | |
| 77 | reset_b(); |
| 78 | strncpy(b, a, 26); |
| 79 | printf("`%s'\n", b); |
| 80 | |
| 81 | reset_b(); |
| 82 | strncpy(b, a, 27); |
| 83 | printf("`%s'\n", b); |
| 84 | |
| 85 | printf("\n"); |
| 86 | |
| 87 | /* testing strncat() */ |
| 88 | |
| 89 | reset_b2(); |
| 90 | printf("`%s'\n", b); |
| 91 | |
| 92 | reset_b2(); |
| 93 | strcat(b, a); |
| 94 | printf("`%s'\n", b); |
| 95 | |
| 96 | reset_b2(); |
| 97 | strncat(b, a, 25); |
| 98 | printf("`%s'\n", b); |
| 99 | |
| 100 | reset_b2(); |
| 101 | strncat(b, a, 26); |
| 102 | printf("`%s'\n", b); |
| 103 | |
| 104 | reset_b2(); |
| 105 | strncat(b, a, 27); |
| 106 | printf("`%s'\n", b); |
| 107 | |
| 108 | /* Nb: can't actually get strcat warning -- if any overlap occurs, it will |
| 109 | always run forever, I think... */ |
| 110 | |
| 111 | strncat(a+20, a, 21); |
| 112 | strncat(a, a+20, 21); |
| 113 | |
| 114 | return 0; |
| 115 | } |