You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: atan.rs
    path of file: ./repos/fontdue/src/platform/float
    
    the code of the file until where you have to start completion: /*
 * origin: FreeBSD /usr/src/lib/msun/src/s_atanf.c
 *
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 *
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */
/// The arctangent function.
pub fn atan(mut x: f32) -> f32 {
    const ATAN_HI: [f32; 4] = [
        4.6364760399e-01, /* atan(0.5)hi 0x3eed6338 */
        7.853981256
    
pub fn atan(mut x: f32) -> f32 {
    const ATAN_HI: [f32; 4] = [
        4.6364760399e-01, /* atan(0.5)hi 0x3eed6338 */
        7.8539812565e-01, /* atan(1.0)hi 0x3f490fda */
        9.8279368877e-01, /* atan(1.5)hi 0x3f7b985e */
        1.5707962513e+00, /* atan(inf)hi 0x3fc90fda */
    ];

    const ATAN_LO: [f32; 4] = [
        5.0121582440e-09, /* atan(0.5)lo 0x31ac3769 */
        3.7748947079e-08, /* atan(1.0)lo 0x33222168 */
        3.4473217170e-08, /* atan(1.5)lo 0x33140fb4 */
        7.5497894159e-08, /* atan(inf)lo 0x33a22168 */
    ];

    const A_T: [f32; 5] =
        [3.3333328366e-01, -1.9999158382e-01, 1.4253635705e-01, -1.0648017377e-01, 6.1687607318e-02];
    let x1p_120 = f32::from_bits(0x03800000); // 0x1p-120 === 2 ^ (-120)

    let z: f32;

    let mut ix = x.to_bits();
    let sign = (ix >> 31) != 0;
    ix &= 0x7fffffff;

    if ix >= 0x4c800000 {
        /* if |x| >= 2**26 */
        if x.is_nan() {
            return x;
        }
        z = ATAN_HI[3] + x1p_120;
        return if sign {
            -z
        } else {
            z
        };
    }
    let id = if ix < 0x3ee00000 {
        /* |x| < 0.4375 */
        if ix < 0x39800000 {
            return x;
        }
        -1
    } else {
        x = super::abs(x);
        if ix < 0x3f980000 {
            /* |x| < 1.1875 */
            if ix < 0x3f300000 {
                /*  7/16 <= |x| < 11/16 */
                x = (2. * x - 1.) / (2. + x);
                0
            } else {
                /* 11/16 <= |x| < 19/16 */
                x = (x - 1.) / (x + 1.);
                1
            }
        } else if ix < 0x401c0000 {
            /* |x| < 2.4375 */
            x = (x - 1.5) / (1. + 1.5 * x);
            2
        } else {
            /* 2.4375 <= |x| < 2**26 */
            x = -1. / x;
            3
        }
    };
    /* end of argument reduction */
    z = x * x;
    let w = z * z;
    /* break sum from i=0 to 10 aT[i]z**(i+1) into odd and even poly */
    let s1 = z * (A_T[0] + w * (A_T[2] + w * A_T[4]));
    let s2 = w * (A_T[1] + w * A_T[3]);
    if id < 0 {
        return x - x * (s1 + s2);
    }
    let id = id as usize;
    let z = ATAN_HI[id] - ((x * (s1 + s2) - ATAN_LO[id]) - x);
    if sign {
        -z
    } else {
        z
    }
}