akbasic/tests/symtab.c

/**
 * @file symtab.c
 * @brief Tests the fixed-capacity open-addressed symbol table.
 */

#include <stdio.h>
#include <string.h>

#include <akbasic/error.h>
#include <akbasic/symtab.h>

#include "testutil.h"

static akbasic_SymbolTable TABLE;

int main(void)
{
    void *value = NULL;
    int64_t ivalue = 0;
    char key[32];
    char longkey[AKBASIC_SYMTAB_MAX_KEY + 2];
    int marker_a = 1;
    int marker_b = 2;
    int i = 0;

    TEST_REQUIRE_OK(akbasic_error_register());
    TEST_REQUIRE_OK(akbasic_symtab_init(&TABLE, 16));

    /* Round-trip both payloads. */
    TEST_REQUIRE_OK(akbasic_symtab_set(&TABLE, "A#", &marker_a, 42));
    TEST_REQUIRE_OK(akbasic_symtab_get(&TABLE, "A#", &value, &ivalue));
    TEST_REQUIRE(value == &marker_a, "wrong pointer payload");
    TEST_REQUIRE_INT(ivalue, 42);

    /* Replacing an existing key must not grow the table. */
    TEST_REQUIRE_OK(akbasic_symtab_set(&TABLE, "A#", &marker_b, 43));
    TEST_REQUIRE_OK(akbasic_symtab_get(&TABLE, "A#", &value, &ivalue));
    TEST_REQUIRE(value == &marker_b, "replacement did not take");
    TEST_REQUIRE_INT(ivalue, 43);
    TEST_REQUIRE_INT(TABLE.count, 1);

    /* A miss is AKERR_KEY, not a crash and not a silent NULL. */
    TEST_REQUIRE_STATUS(akbasic_symtab_get(&TABLE, "B$", &value, &ivalue), AKERR_KEY);

    /*
     * Collisions. Sixteen distinct keys in a sixteen-slot table guarantees the
     * probe sequence is exercised, and the last insert has exactly one slot to
     * find.
     */
    TEST_REQUIRE_OK(akbasic_symtab_clear(&TABLE));
    for ( i = 0; i < 16; i++ ) {
	snprintf(key, sizeof(key), "V%d#", i);
	TEST_REQUIRE_OK(akbasic_symtab_set(&TABLE, key, NULL, i));
    }
    for ( i = 0; i < 16; i++ ) {
	snprintf(key, sizeof(key), "V%d#", i);
	TEST_REQUIRE_OK(akbasic_symtab_get(&TABLE, key, NULL, &ivalue));
	TEST_REQUIRE_INT(ivalue, i);
    }

    /* Seventeenth key into a sixteen-slot table: full, and it says so. */
    TEST_REQUIRE_STATUS(akbasic_symtab_set(&TABLE, "OVERFLOW#", NULL, 0), AKBASIC_ERR_BOUNDS);

    /* Clear keeps the capacity but drops the contents. */
    TEST_REQUIRE_OK(akbasic_symtab_clear(&TABLE));
    TEST_REQUIRE_INT(TABLE.count, 0);
    TEST_REQUIRE_INT(TABLE.capacity, 16);
    TEST_REQUIRE_STATUS(akbasic_symtab_get(&TABLE, "V0#", NULL, NULL), AKERR_KEY);

    /*
     * Boundary keys. Mutation testing found that nothing exercised a key at the
     * length limit, so every `AKBASIC_SYMTAB_MAX_KEY - 1` in the copy and its
     * NUL terminator could be perturbed to `+ 1` or `- 0` and survive. A key one
     * character under the limit must round-trip exactly; one *at* the limit must
     * be refused rather than silently truncated.
     */
    TEST_REQUIRE_OK(akbasic_symtab_clear(&TABLE));
    memset(longkey, 'K', AKBASIC_SYMTAB_MAX_KEY - 1);
    longkey[AKBASIC_SYMTAB_MAX_KEY - 1] = '\0';
    TEST_REQUIRE_OK(akbasic_symtab_set(&TABLE, longkey, &marker_a, 7));
    TEST_REQUIRE_OK(akbasic_symtab_get(&TABLE, longkey, &value, &ivalue));
    TEST_REQUIRE(value == &marker_a, "a maximum-length key must round-trip");
    TEST_REQUIRE_INT(ivalue, 7);
    TEST_REQUIRE_INT(strlen(TABLE.slots[0].key) + strlen(TABLE.slots[1].key) +
		     strlen(TABLE.slots[2].key) + strlen(TABLE.slots[3].key) +
		     strlen(TABLE.slots[4].key) + strlen(TABLE.slots[5].key) +
		     strlen(TABLE.slots[6].key) + strlen(TABLE.slots[7].key) +
		     strlen(TABLE.slots[8].key) + strlen(TABLE.slots[9].key) +
		     strlen(TABLE.slots[10].key) + strlen(TABLE.slots[11].key) +
		     strlen(TABLE.slots[12].key) + strlen(TABLE.slots[13].key) +
		     strlen(TABLE.slots[14].key) + strlen(TABLE.slots[15].key),
		     AKBASIC_SYMTAB_MAX_KEY - 1);

    memset(longkey, 'K', AKBASIC_SYMTAB_MAX_KEY);
    longkey[AKBASIC_SYMTAB_MAX_KEY] = '\0';
    TEST_REQUIRE_STATUS(akbasic_symtab_set(&TABLE, longkey, NULL, 0), AKBASIC_ERR_BOUNDS);
    TEST_REQUIRE_STATUS(akbasic_symtab_get(&TABLE, longkey, NULL, NULL), AKERR_KEY);

    /*
     * A freshly initialised table is empty and its slots are clear. Mutation
     * found that deleting the memset or the count reset in init() survived,
     * because every other assertion here goes through set() first.
     */
    TEST_REQUIRE_OK(akbasic_symtab_init(&TABLE, 16));
    TEST_REQUIRE_INT(TABLE.count, 0);
    for ( i = 0; i < 16; i++ ) {
	TEST_REQUIRE(!TABLE.slots[i].used, "slot %d should be unused after init", i);
	TEST_REQUIRE(TABLE.slots[i].key[0] == '\0', "slot %d key should be clear", i);
	TEST_REQUIRE(TABLE.slots[i].value == NULL, "slot %d value should be NULL", i);
	TEST_REQUIRE_INT(TABLE.slots[i].ivalue, 0);
    }

    /*
     * Probing must start where the hash says. Mutation found that seeding the
     * probe index or the loop counter to 1, or dropping the hash call entirely,
     * survived -- a table that ignores its hash still works, just slowly. Assert
     * placement instead: with capacity 1 there is exactly one slot, so a second
     * distinct key has nowhere to go.
     */
    TEST_REQUIRE_OK(akbasic_symtab_init(&TABLE, 1));
    TEST_REQUIRE_OK(akbasic_symtab_set(&TABLE, "ONLY#", NULL, 1));
    TEST_REQUIRE(TABLE.slots[0].used, "the single slot must be the one used");
    TEST_REQUIRE_STATUS(akbasic_symtab_set(&TABLE, "OTHER#", NULL, 2), AKBASIC_ERR_BOUNDS);
    TEST_REQUIRE_OK(akbasic_symtab_get(&TABLE, "ONLY#", NULL, &ivalue));
    TEST_REQUIRE_INT(ivalue, 1);

    /* Argument validation. */
    TEST_REQUIRE_STATUS(akbasic_symtab_init(NULL, 16), AKERR_NULLPOINTER);
    TEST_REQUIRE_STATUS(akbasic_symtab_init(&TABLE, 0), AKBASIC_ERR_BOUNDS);
    TEST_REQUIRE_STATUS(akbasic_symtab_init(&TABLE, AKBASIC_SYMTAB_MAX_SLOTS + 1),
			AKBASIC_ERR_BOUNDS);

    return akbasic_test_failures;
}