[c] hash function for string

First, you generally do not want to use a cryptographic hash for a hash table. An algorithm that's very fast by cryptographic standards is still excruciatingly slow by hash table standards.

Second, you want to ensure that every bit of the input can/will affect the result. One easy way to do that is to rotate the current result by some number of bits, then XOR the current hash code with the current byte. Repeat until you reach the end of the string. Note that you generally do not want the rotation to be an even multiple of the byte size either.

For example, assuming the common case of 8 bit bytes, you might rotate by 5 bits:

int hash(char const *input) { 
    int result = 0x55555555;

    while (*input) { 
        result ^= *input++;
        result = rol(result, 5);
    }
}

Edit: Also note that 10000 slots is rarely a good choice for a hash table size. You usually want one of two things: you either want a prime number as the size (required to ensure correctness with some types of hash resolution) or else a power of 2 (so reducing the value to the correct range can be done with a simple bit-mask).

Examples related to c

conflicting types for 'outchar' Can't compile C program on a Mac after upgrade to Mojave Program to find largest and second largest number in array Prime numbers between 1 to 100 in C Programming Language In c, in bool, true == 1 and false == 0? How I can print to stderr in C? Visual Studio Code includePath "error: assignment to expression with array type error" when I assign a struct field (C) Compiling an application for use in highly radioactive environments How can you print multiple variables inside a string using printf?

Examples related to algorithm

How can I tell if an algorithm is efficient? Find the smallest positive integer that does not occur in a given sequence Efficiently getting all divisors of a given number Peak signal detection in realtime timeseries data What is the optimal algorithm for the game 2048? How can I sort a std::map first by value, then by key? Finding square root without using sqrt function? Fastest way to flatten / un-flatten nested JSON objects Mergesort with Python Find common substring between two strings

Examples related to hash

php mysqli_connect: authentication method unknown to the client [caching_sha2_password] What is Hash and Range Primary Key? How to create a laravel hashed password Hashing a file in Python PHP salt and hash SHA256 for login password Append key/value pair to hash with << in Ruby Are there any SHA-256 javascript implementations that are generally considered trustworthy? How do I generate a SALT in Java for Salted-Hash? What does hash do in python? Hashing with SHA1 Algorithm in C#

Examples related to dictionary

JS map return object python JSON object must be str, bytes or bytearray, not 'dict Python update a key in dict if it doesn't exist How to update the value of a key in a dictionary in Python? How to map an array of objects in React C# Dictionary get item by index Are dictionaries ordered in Python 3.6+? Split / Explode a column of dictionaries into separate columns with pandas Writing a dictionary to a text file? enumerate() for dictionary in python

Examples related to hashtable

How do I encode a JavaScript object as JSON? Hash table runtime complexity (insert, search and delete) Looping through a hash, or using an array in PowerShell Hash function for a string hash function for string iterating through Enumeration of hastable keys throws NoSuchElementException error How do HashTables deal with collisions? Good Hash Function for Strings Iterating over and deleting from Hashtable in Java What happens when a duplicate key is put into a HashMap?