#include "cve.h"

#define ROW_SWEEP_ALG(op)                                                     \
    /* Iterate `(block_size_i, ncol)` submatrix blocks. */                    \
    for (i = 0; i < nrow; i += block_size_i) {                                \
        /* Set `A` and `C` to block beginning. */                             \
        A = A_block;                                                          \
        C = C_block;                                                          \
        /* Get current block's row size. */                                   \
        block_size_i = nrow - i;                                              \
        if (block_size_i > block_size) {                                      \
            block_size_i = block_size;                                        \
        }                                                                     \
        /* Perform element wise operation for block. */                       \
        for (; A < A_end; A += nrow, C += nrow) {                             \
            for (j = 0; j < block_size_i; ++j) {                              \
                C[j] = (A[j]) op (v[j]);                                      \
            }                                                                 \
        }                                                                     \
        /* Step one block forth. */                                           \
        A_block += block_size_i;                                              \
        C_block += block_size_i;                                              \
        v += block_size_i;                                                    \
    }

/* C[, j] = A[, j] op v for each j = 1 to ncol with op as one of +, -, *, / */
void rowSweep(const double *A, const int nrow, const int ncol,
              const char* op,
              const double *v, // vector of length nrow
              double *C) {
    int i, j, block_size, block_size_i;
    const double *A_block = A;
    double *C_block = C;
    const double *A_end = A + nrow * ncol;

    if (nrow > CVE_MEM_CHUNK_SMALL) { // small because 3 vectors in cache
        block_size = CVE_MEM_CHUNK_SMALL;
    } else {
        block_size = nrow;
    }

    if (*op == '+') {
        ROW_SWEEP_ALG(+)
    } else if (*op == '-') {
        ROW_SWEEP_ALG(-)
    } else if (*op == '*') {
        ROW_SWEEP_ALG(*)
    } else if (*op == '/') {
        ROW_SWEEP_ALG(/)
    }
}