""" vec_test_helpers

This module is for reusable helper functions used by the templates.
"""
import numpy as np

def is_widening(op_code):
    """Check if a particular op_code is a widening type."""
    return op_code[1] == 'w'

def is_unsigned(op_code):
    """Check if a particular op_code is a unsigned type."""
    return op_code[-1] == 'u'

def get_sews(op_code):
    """Given an op_code return a list of valid element widths."""
    return [8, 16] if is_widening(op_code) else [8, 16, 32]

def get_lmuls(op_code):
    """Given an op_code return an iterable if valid lmuls."""
    return [1, 2, 4] if is_widening(op_code) else [1, 2, 4, 8]

def get_dest_type(op_code, sew):
    """Return a destination type for a op_code and element width."""
    type_fmt = "%sint%d_t"
    sign_type  = "u" if is_unsigned(op_code) else ""
    dest_sew = sew * 2 if is_widening(op_code) else sew
    return type_fmt % (sign_type, dest_sew)

def get_src_type(op_code, sew):
    """Return a source type for an op_code and element width."""
    type_fmt = "%sint%d_t"
    sign_type = "u" if is_unsigned(op_code) else ""
    return type_fmt % (sign_type, sew)

def get_ref_opcode(op_code):
    """Return the name of the reference code in the softrvv library."""
    return op_code[:-1] if is_unsigned(op_code) else op_code

def get_imms(op_code):
    """Return a list of valid immediate values for a op code."""
    if op_code in ['vsll', 'vsrl', 'vsra']:
        # Left and right shift immediates must be [0,31]
        return np.linspace(0, 31, 8, dtype=np.int32)
    else:
        # Immediate values must be [-16, 15]
        return np.linspace(-16, 15, 7, dtype=np.int32)