diff options
Diffstat (limited to 'misc/hsearch_r.c')
| -rw-r--r-- | misc/hsearch_r.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/misc/hsearch_r.c b/misc/hsearch_r.c index 81c27d8..af55212 100644 --- a/misc/hsearch_r.c +++ b/misc/hsearch_r.c @@ -19,7 +19,7 @@ #include <errno.h> #include <malloc.h> #include <string.h> - +#include <stdint.h> #include <search.h> /* [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986 @@ -46,15 +46,12 @@ static int isprime (unsigned int number) { /* no even number will be passed */ - unsigned int div = 3; - - while (div * div < number && number % div != 0) - div += 2; - - return number % div != 0; + for (unsigned int div = 3; div <= number / div; div += 2) + if (number % div == 0) + return 0; + return 1; } - /* Before using the hash table we must allocate memory for it. Test for an existing table are done. We allocate one element more as the found prime number says. This is done for more effective @@ -81,10 +78,19 @@ hcreate_r (nel, htab) use will not work. */ if (nel < 3) nel = 3; - /* Change nel to the first prime number not smaller as nel. */ - nel |= 1; /* make odd */ - while (!isprime (nel)) - nel += 2; + + /* Change nel to the first prime number in the range [nel, UINT_MAX - 2], + The '- 2' means 'nel += 2' cannot overflow. */ + for (nel |= 1; ; nel += 2) + { + if (UINT_MAX - 2 < nel) + { + __set_errno (ENOMEM); + return 0; + } + if (isprime (nel)) + break; + } htab->size = nel; htab->filled = 0; |