utils.c

//
//  utils.c
//
//  Created by Owatch on 29/12/2016.
//

#include "utils.h"

#pragma mark Private Function Declarations


#pragma mark Function Declarations: Allocative Operations

/* Allocates and returns a vector of length 'length'*/
Vector *newVector(size_t length) {
    if (length <= 0) return NULL;
    Vector *vector = malloc(sizeof(Vector));
    Number *array = malloc(length * sizeof(Number));
    if (vector == NULL || array == NULL) return NULL;
    vector->array = array;
    vector->length = length;
    return vector;
}

/* Allocates and returns a copy of an existing vector */
Vector *copyVector(Vector *vector) {
    if (vector == NULL) return NULL;
    Vector *copy = malloc(sizeof(Vector));
    Number *array = malloc(vector->length * sizeof(Number));
    if (copy == NULL || array == NULL) return NULL;
    copy->length = vector->length;
    copy->array = memcpy(array,vector->array,vector->length * sizeof(Number));
    return copy;
}

/* Allocates and returns a vector containing all odd elements */
Vector *getOdds(Vector *vector) {
    size_t n = vector->length/2 - (vector->length % 2);
    Vector *odds = newVector(n);
    int k = 1;
    for (int i = 0; i < n; i++) {
        odds->array[i] = newNumber(vector->array[k].r, vector->array[k].c);
        k += 2;
    }
    return odds;
}

/* Allocates and returns a vector containing all even elements */
Vector *getEvens(Vector *vector) {
    size_t n = vector->length/2;
    Vector *evens = newVector(n);
    int k = 0;
    for (int i = 0; i < n; i++) {
        evens->array[i] = vector->array[k];
        k += 2;
    }
    return evens;
}

#pragma mark Function Declarations: Instance Operations

/* Returns true if a number is zero, else false */
int isZero(Number number) {
    return (number.r == 0 && number.c == 0);
}

/* Copies the contents of the vector 'a' to vector 'b' at the given index. Returns the pointer to vector 'b' */
Vector *vectorWithVector(Vector *b, Vector *a, unsigned long index) {
    if (a == NULL || b == NULL) return NULL;
    int copySize = a->length;
    if (a->length + index > b->length) {
        copySize = b->length - index;
    }
    memcpy(b->array + index, a->array, copySize * sizeof(Number));
    return b;
}

/* Copies the first vector into the second vector at the given index */
Vector *copyInto(Vector *b, Vector *a, int index) {
    int max = (index + a->length) < b->length ? (index + a->length) : b->length;
    for (int i = index; i < max; i++) {
        b->array[i] = a->array[i - index];
    }
    return b;
}

/* Sets all numbers in a vector to zero, returns pointer */
Vector *zeroVector(Vector *vector) {
    for (int i = 0; i < vector->length; i++) {
        vector->array[i] = newNumber(0,0);
    }
    return vector;
}

/* Prints a Vector instance */
void printVector(Vector *vector) {
    if (vector == NULL) return;
    putchar('[');
    for (int i = 0; i < vector->length; i++) {
        printNumber(vector->array[i]);
        if (i < vector->length - 1) printf(", ");
    }
    putchar(']');
    putchar('\n');
}

/* Free's a Vector instance */
void freeVector(Vector *vector) {
    free(vector->array);
    free(vector);
}

#pragma mark Function Declarations: Numeric Operations

/* Returns an initialized Number instance */
Number newNumber(double_t r, double_t c) {
    return (Number){.r = r, .c = c};
}

/* Returns the sum of numbers 'a' and 'b' */
Number sum(Number a, Number b) {
    return (Number){a.r + b.r, a.c + b.c};
}

/* Returns the difference of numbers 'a' and 'b' (a-b) */
Number diff(Number a, Number b) {
    return (Number){a.r - b.r, a.c - b.c};
}

/* Returns the product between numbers 'a' and 'b' */
Number product(Number a, Number b) {
    return (Number){a.r * b.r - a.c * b.c, a.r * b.c + b.r * a.c};
}

/* Returns a negated number */
Number negative(Number number) {
    return (Number){-number.r, -number.c};
}

/* Prints a number */
void printNumber(Number number) {
    putchar('(');
    if (number.r && number.c) {
        printf("%.3f %c %.3fi",number.r, (number.c < 0 ? '-' : '+'), fabs(number.c));

    } else if (!number.r && !number.c) {
        printf("%.3f",0.0);

    } else if (number.r) {
        printf("%.3f",number.r);

    } else if (number.c) {
        printf("%.3fi",number.c);

    }
    putchar(')');
}