struct-vis/table.h

#define TABLE_KEY_SIZE 64
#define TABLE_NUM_LANES 32
static inline unsigned int APHash(const char* str, unsigned int length) {
   unsigned int hash = 0xAAAAAAAA;
   unsigned int i    = 0;

   for (i = 0; i < length; ++str, ++i)
   {
      hash ^= ((i & 1) == 0) ? (  (hash <<  7) ^ (*str) * (hash >> 3)) :
                               (~((hash << 11) + ((*str) ^ (hash >> 5))));
   }

   return hash;
}

static inline uint32_t fastModuloReductionDanielLemire(uint32_t v, uint32_t c) {
    return (((uint64_t)v) * ((uint64_t)c)) >> 32;
}

static inline uint32_t hash(const char* key, uint32_t keyLength, uint32_t capacity) {
    uint32_t value = APHash(key, keyLength);

    return fastModuloReductionDanielLemire(value, capacity);
}

typedef struct TableEntry {
    struct TableEntry* next;

    const char key[TABLE_KEY_SIZE];
    ssize_t size;
    ssize_t align;
} TableEntry;

typedef struct Table {
    TableEntry **entries;
} Table;

static inline TableEntry* lookup(Table *table, const char key[TABLE_KEY_SIZE]) {
    TableEntry *entry = table->entries[hash(key, TABLE_KEY_SIZE, TABLE_NUM_LANES)];

    for (; entry != NULL; entry = entry->next) {
        if (memcmp(entry->key, key, TABLE_KEY_SIZE) == 0) {
            return entry;
        }
    }

    return NULL;
}

static inline void insert(Table *table, const char key[TABLE_KEY_SIZE], ssize_t size, ssize_t align) {
    TableEntry *entry = lookup(table, key);

    if (!entry) { // no entry with that key exists
        entry = (TableEntry*) calloc(sizeof(TableEntry), 1);
        strWrite((char*)entry->key, key, TABLE_KEY_SIZE);
        entry->size = size;
        entry->align = align;

        unsigned int hashValue = hash(key, TABLE_KEY_SIZE, TABLE_NUM_LANES);
        entry->next = table->entries[hashValue];
        table->entries[hashValue] = entry;

    } else { // entry already exists, replace its value
        entry->size = size;
        entry->align = align;
    }
}

static inline void insertPadZeroes(Table* table, const char* keyToPad, ssize_t size, ssize_t align) {
    char scratch[64] = { 0 };
    for (int i = 0; i < TABLE_KEY_SIZE; i++) {
        if (keyToPad[i] == '\0') break;
        scratch[i] = keyToPad[i];
    }

    insert(table, scratch, size, align);
}

static inline void traversePrint(Table *table) {
    for (unsigned int i = 0; i < TABLE_NUM_LANES; i++) {
        TableEntry *entry = table->entries[i];

        while (entry != NULL) {
            printf("entry key: %-64s, size: %lu, align: %lu\n", entry->key, entry->size, entry->align);
            entry = entry->next;
        }
    }
}

static inline Table* initTable() {
    Table *table = malloc(sizeof(Table));
    table->entries = (TableEntry**) calloc(sizeof(TableEntry*), TABLE_NUM_LANES);

    // alignof === sizeof for primitive data types, C99 doesn't have 'alignof'
    insertPadZeroes(table, "char",                   sizeof(char),                   sizeof(char));
    insertPadZeroes(table, "signed char",            sizeof(signed char),            sizeof(signed char));
    insertPadZeroes(table, "unsigned char",          sizeof(unsigned char),          sizeof(unsigned char));
    insertPadZeroes(table, "short",                  sizeof(short),                  sizeof(short));
    insertPadZeroes(table, "short int",              sizeof(short int),              sizeof(short int));
    insertPadZeroes(table, "signed short",           sizeof(signed short),           sizeof(signed short));
    insertPadZeroes(table, "signed short int",       sizeof(signed short int),       sizeof(signed short int));
    insertPadZeroes(table, "unsigned short",         sizeof(unsigned short),         sizeof(unsigned short));
    insertPadZeroes(table, "unsigned short int",     sizeof(unsigned short int),     sizeof(unsigned short int));
    insertPadZeroes(table, "int",                    sizeof(int),                    sizeof(int));
    insertPadZeroes(table, "signed",                 sizeof(signed),                 sizeof(signed));
    insertPadZeroes(table, "signed int",             sizeof(signed int),             sizeof(signed int));
    insertPadZeroes(table, "unsigned",               sizeof(unsigned),               sizeof(unsigned));
    insertPadZeroes(table, "unsigned int",           sizeof(unsigned int),           sizeof(unsigned int));
    insertPadZeroes(table, "long",                   sizeof(long),                   sizeof(long));
    insertPadZeroes(table, "long int",               sizeof(long int),               sizeof(long int));
    insertPadZeroes(table, "signed long",            sizeof(signed long),            sizeof(signed long));
    insertPadZeroes(table, "signed long int",        sizeof(signed long int),        sizeof(signed long int));
    insertPadZeroes(table, "unsigned long",          sizeof(unsigned long),          sizeof(unsigned long));
    insertPadZeroes(table, "unsigned long int",      sizeof(unsigned long int),      sizeof(unsigned long int));
    insertPadZeroes(table, "long long",              sizeof(long long),              sizeof(long long));
    insertPadZeroes(table, "long long int",          sizeof(long long int),          sizeof(long long int));
    insertPadZeroes(table, "signed long long",       sizeof(signed long long),       sizeof(signed long long));
    insertPadZeroes(table, "signed long long int",   sizeof(signed long long int),   sizeof(signed long long int));
    insertPadZeroes(table, "unsigned long long",     sizeof(unsigned long long),     sizeof(unsigned long long));
    insertPadZeroes(table, "unsigned long long int", sizeof(unsigned long long int), sizeof(unsigned long long int));
    insertPadZeroes(table, "float",                  sizeof(float),                  sizeof(float));
    insertPadZeroes(table, "double",                 sizeof(double),                 sizeof(double));
    insertPadZeroes(table, "long double",            sizeof(long double),            sizeof(long double));

    insertPadZeroes(table, "size_t",                 sizeof(size_t),                 sizeof(size_t));
    insertPadZeroes(table, "ssize_t",                sizeof(ssize_t),                sizeof(ssize_t));
    insertPadZeroes(table, "bool",                   sizeof(bool),                   sizeof(bool));
    insertPadZeroes(table, "_Bool",                  sizeof(_Bool),                  sizeof(_Bool));

    return table;
}

static Table *typeTable;