#!/usr/bin/python2
"""
generate_ufuncs.py

Generate Ufunc definition source files for scipy.special.  Produces
files '_ufuncs.c' and '_ufuncs_cxx.c' by first producing Cython.

This will generate both calls to PyUFunc_FromFuncAndData and the
required ufunc inner loops.

The syntax in the ufunc signature list is

    <line>:           <ufunc_name> '--' <kernels> '--' <headers>
    <kernels>:        <function> [',' <function>]*
    <function>:       <name> ':' <input> '*' <output>
                        '->' <retval> '*' <ignored_retval>
    <input>:          <typecode>*
    <output>:         <typecode>*
    <retval>:         <typecode>?
    <ignored_retval>: <typecode>?
    <headers>:        <header_name> [',' <header_name>]*

The input parameter types are denoted by single character type
codes, according to

   'f': 'float'
   'd': 'double'
   'g': 'long double'
   'F': 'float complex'
   'D': 'double complex'
   'G': 'long double complex'
   'i': 'int'
   'l': 'long'
   'v': 'void'

If multiple kernel functions are given for a single ufunc, the one
which is used is determined by the standard ufunc mechanism. Kernel
functions that are listed first are also matched first against the
ufunc input types, so functions listed earlier take precedence.

In addition, versions with casted variables, such as d->f,D->F and
i->d are automatically generated.

There should be either a single header that contains all of the kernel
functions listed, or there should be one header for each kernel
function. Cython pxd files are allowed in addition to .h files.

Cython functions may use fused types, but the names in the list
should be the specialized ones, such as 'somefunc[float]'.

Floating-point exceptions inside these Ufuncs are converted to
special function errors --- which are separately controlled by the
user, and off by default, as they are usually not especially useful
for the user.

"""

from __future__ import division, print_function, absolute_import

#---------------------------------------------------------------------------------
# Ufunc listing
#---------------------------------------------------------------------------------

#
#

# Ufuncs without C++
UFUNCS = """
_lambertw -- lambertw_scalar: Dld->D                       -- lambertw.pxd
logit -- logitf: f->f, logit: d->d, logitl: g->g           -- _logit.h
expit -- expitf: f->f, expit: d->d, expitl: g->g           -- _logit.h
bdtrc -- bdtrc: iid->d, bdtrc_unsafe: ddd->d               -- cephes.h, _legacy.pxd
bdtr -- bdtr: iid->d, bdtr_unsafe: ddd->d                  -- cephes.h, _legacy.pxd
bdtri -- bdtri: iid->d, bdtri_unsafe: ddd->d               -- cephes.h, _legacy.pxd
binom -- binom: dd->d                                      -- orthogonal_eval.pxd
btdtr -- btdtr: ddd->d                                     -- cephes.h
btdtri -- incbi: ddd->d                                    -- cephes.h
fdtrc -- fdtrc: ddd->d                                     -- cephes.h
fdtr -- fdtr: ddd->d                                       -- cephes.h
fdtri -- fdtri: ddd->d                                     -- cephes.h
gdtrc -- gdtrc: ddd->d                                     -- cephes.h
gdtr -- gdtr: ddd->d                                       -- cephes.h
hyp2f1 -- hyp2f1: dddd->d, chyp2f1_wrap: dddD->D           -- cephes.h, specfun_wrappers.h
hyp1f1 -- hyp1f1_wrap: ddd->d, chyp1f1_wrap: ddD->D        -- specfun_wrappers.h
hyperu -- hypU_wrap: ddd->d                                -- specfun_wrappers.h
hyp2f0 -- hyp2f0: dddi*d->d, hyp2f0_unsafe: dddd*d->d      -- cephes.h, _legacy.pxd
hyp1f2 -- onef2: dddd*d->d                                 -- cephes.h
hyp3f0 -- threef0: dddd*d->d                               -- cephes.h
betainc -- incbet: ddd->d                                  -- cephes.h
betaincinv -- incbi: ddd->d                                -- cephes.h
nbdtrc -- nbdtrc: iid->d, nbdtrc_unsafe: ddd->d            -- cephes.h, _legacy.pxd
nbdtr -- nbdtr: iid->d, nbdtr_unsafe: ddd->d               -- cephes.h, _legacy.pxd
nbdtri -- nbdtri: iid->d, nbdtri_unsafe: ddd->d            -- cephes.h, _legacy.pxd
beta -- beta: dd->d                                        -- cephes.h
betaln -- lbeta: dd->d                                     -- cephes.h
cbrt -- cbrt: d->d                                         -- cephes.h
chdtrc -- chdtrc: dd->d                                    -- cephes.h
chdtr -- chdtr: dd->d                                      -- cephes.h
chdtri -- chdtri: dd->d                                    -- cephes.h
ellipeinc -- ellie: dd->d                                  -- cephes.h
ellipkinc -- ellik: dd->d                                  -- cephes.h
ellipe -- ellpe: d->d                                      -- cephes.h
ellipkm1 -- ellpk: d->d                                    -- cephes.h
eval_jacobi --      eval_jacobi[double]: dddd->d,     eval_jacobi[double complex]: dddD->D,     eval_jacobi_l: lddd->d -- orthogonal_eval.pxd
eval_sh_jacobi --   eval_sh_jacobi[double]: dddd->d,  eval_sh_jacobi[double complex]: dddD->D,  eval_sh_jacobi_l: lddd->d -- orthogonal_eval.pxd
eval_gegenbauer --  eval_gegenbauer[double]: ddd->d,  eval_gegenbauer[double complex]: ddD->D,  eval_gegenbauer_l: ldd->d -- orthogonal_eval.pxd
eval_chebyt --      eval_chebyt[double]: dd->d,       eval_chebyt[double complex]: dD->D,       eval_chebyt_l: ld->d -- orthogonal_eval.pxd
eval_chebyu --      eval_chebyu[double]: dd->d,       eval_chebyu[double complex]: dD->D,       eval_chebyu_l: ld->d -- orthogonal_eval.pxd
eval_chebyc --      eval_chebyc[double]: dd->d,       eval_chebyc[double complex]: dD->D,       eval_chebyc_l: ld->d -- orthogonal_eval.pxd
eval_chebys --      eval_chebys[double]: dd->d,       eval_chebys[double complex]: dD->D,       eval_chebys_l: ld->d -- orthogonal_eval.pxd
eval_sh_chebyt --   eval_sh_chebyt[double]: dd->d,    eval_sh_chebyt[double complex]: dD->D,    eval_sh_chebyt_l:ld->d -- orthogonal_eval.pxd
eval_sh_chebyu --   eval_sh_chebyu[double]: dd->d,    eval_sh_chebyu[double complex]: dD->D,    eval_sh_chebyu_l:ld->d -- orthogonal_eval.pxd
eval_legendre --    eval_legendre[double]: dd->d,     eval_legendre[double complex]: dD->D,     eval_legendre_l: ld->d -- orthogonal_eval.pxd
eval_sh_legendre -- eval_sh_legendre[double]: dd->d,  eval_sh_legendre[double complex]: dD->D,  eval_sh_legendre_l:ld->d -- orthogonal_eval.pxd
eval_genlaguerre -- eval_genlaguerre[double]: ddd->d, eval_genlaguerre[double complex]: ddD->D, eval_genlaguerre_l:ldd->d -- orthogonal_eval.pxd
eval_laguerre --    eval_laguerre[double]: dd->d,     eval_laguerre[double complex]: dD->D,     eval_laguerre_l:ld->d -- orthogonal_eval.pxd
eval_hermite  -- eval_hermite: ld->d                       -- orthogonal_eval.pxd
eval_hermitenorm -- eval_hermitenorm: ld->d                -- orthogonal_eval.pxd
exp10 -- exp10: d->d                                       -- cephes.h
exp2 -- exp2: d->d                                         -- cephes.h
gamma -- Gamma: d->d, cgamma_wrap: D->D                    -- cephes.h, specfun_wrappers.h
gammaln -- lgam: d->d, clngamma_wrap: D->D                 -- cephes.h, specfun_wrappers.h
gammasgn -- gammasgn: d->d                                 -- c_misc/misc.h
i0 -- i0: d->d                                             -- cephes.h
i0e -- i0e: d->d                                           -- cephes.h
i1 -- i1: d->d                                             -- cephes.h
i1e -- i1e: d->d                                           -- cephes.h
gammaincc -- igamc: dd->d                                  -- cephes.h
gammainc -- igam: dd->d                                    -- cephes.h
gammaincinv -- gammaincinv: dd->d                          -- cephes.h
gammainccinv -- igami: dd->d                               -- cephes.h
iv -- iv: dd->d, cbesi_wrap: dD->D                         -- cephes.h, amos_wrappers.h
ive -- cbesi_wrap_e_real: dd->d, cbesi_wrap_e: dD->D       -- amos_wrappers.h
ellipj -- ellpj: dd*dddd->*i                               -- cephes.h
expn -- expn: id->d, expn_unsafe: dd->d                    -- cephes.h, _legacy.pxd
exp1 -- exp1_wrap: d->d, cexp1_wrap: D->D                  -- specfun_wrappers.h
expi -- expi_wrap: d->d, cexpi_wrap: D->D                  -- specfun_wrappers.h
kn -- kn: id->d, kn_unsafe: dd->d                          -- cephes.h, _legacy.pxd
pdtrc -- pdtrc: id->d, pdtrc_unsafe: dd->d                 -- cephes.h, _legacy.pxd
pdtr -- pdtr: id->d, pdtr_unsafe: dd->d                    -- cephes.h, _legacy.pxd
pdtri -- pdtri: id->d, pdtri_unsafe: dd->d                 -- cephes.h, _legacy.pxd
yn -- yn: id->d, yn_unsafe: dd->d                          -- cephes.h, _legacy.pxd
smirnov -- smirnov: id->d, smirnov_unsafe: dd->d           -- cephes.h, _legacy.pxd
smirnovi -- smirnovi: id->d, smirnovi_unsafe: dd->d        -- cephes.h, _legacy.pxd
airy -- airy: d*dddd->*i, cairy_wrap: D*DDDD->*i           -- cephes.h, amos_wrappers.h
itairy -- itairy_wrap: d*dddd->*i                          -- specfun_wrappers.h
airye -- cairy_wrap_e_real: d*dddd->*i, cairy_wrap_e: D*DDDD->*i -- amos_wrappers.h
fresnel -- fresnl: d*dd->*i, cfresnl_wrap: D*DD->*i        -- cephes.h, specfun_wrappers.h
shichi -- shichi: d*dd->*i                                 -- cephes.h
sici -- sici: d*dd->*i                                     -- cephes.h
itj0y0 -- it1j0y0_wrap: d*dd->*i                           -- specfun_wrappers.h
it2j0y0 -- it2j0y0_wrap: d*dd->*i                          -- specfun_wrappers.h
iti0k0 -- it1i0k0_wrap: d*dd->*i                           -- specfun_wrappers.h
it2i0k0 -- it2i0k0_wrap: d*dd->*i                          -- specfun_wrappers.h
j0 -- j0: d->d                                             -- cephes.h
y0 -- y0: d->d                                             -- cephes.h
j1 -- j1: d->d                                             -- cephes.h
y1 -- y1: d->d                                             -- cephes.h
jv -- jv: dd->d, cbesj_wrap: dD->D                         -- cephes.h, amos_wrappers.h
jve -- cbesj_wrap_e_real: dd->d, cbesj_wrap_e: dD->D       -- amos_wrappers.h
yv -- yv: dd->d, cbesy_wrap: dD->D                         -- cephes.h, amos_wrappers.h
yve -- cbesy_wrap_e_real: dd->d, cbesy_wrap_e: dD->D       -- amos_wrappers.h
k0 -- k0: d->d                                             -- cephes.h
k0e -- k0e: d->d                                           -- cephes.h
k1 -- k1: d->d                                             -- cephes.h
k1e -- k1e: d->d                                           -- cephes.h
kv -- cbesk_wrap_real: dd->d, cbesk_wrap: dD->D            -- amos_wrappers.h
kve -- cbesk_wrap_e_real: dd->d, cbesk_wrap_e: dD->D       -- amos_wrappers.h
hankel1 -- cbesh_wrap1: dD->D                              -- amos_wrappers.h
hankel1e -- cbesh_wrap1_e: dD->D                           -- amos_wrappers.h
hankel2 -- cbesh_wrap2: dD->D                              -- amos_wrappers.h
hankel2e -- cbesh_wrap2_e: dD->D                           -- amos_wrappers.h
ndtr -- ndtr: d->d                                         -- cephes.h
log_ndtr -- log_ndtr: d->d                                 -- cephes.h
ndtri -- ndtri: d->d                                       -- cephes.h
psi -- psi: d->d, cpsi_wrap: D->D                          -- cephes.h, specfun_wrappers.h
rgamma -- rgamma: d->d, crgamma_wrap: D->D                 -- cephes.h, specfun_wrappers.h
round -- round: d->d                                       -- cephes.h
sindg -- sindg: d->d                                       -- cephes.h
cosdg -- cosdg: d->d                                       -- cephes.h
radian -- radian: ddd->d                                   -- cephes.h
tandg -- tandg: d->d                                       -- cephes.h
cotdg -- cotdg: d->d                                       -- cephes.h
log1p -- log1p: d->d                                       -- cephes.h
expm1 -- expm1: d->d                                       -- cephes.h
cosm1 -- cosm1: d->d                                       -- cephes.h
spence -- spence: d->d                                     -- cephes.h
zetac -- zetac: d->d                                       -- cephes.h
struve -- struve_wrap: dd->d                               -- specfun_wrappers.h
modstruve -- modstruve_wrap: dd->d                         -- specfun_wrappers.h
itstruve0 -- itstruve0_wrap: d->d                          -- specfun_wrappers.h
it2struve0 -- it2struve0_wrap: d->d                        -- specfun_wrappers.h
itmodstruve0 -- itmodstruve0_wrap: d->d                    -- specfun_wrappers.h
kelvin -- kelvin_wrap: d*DDDD->*i                          -- specfun_wrappers.h
ber -- ber_wrap: d->d                                      -- specfun_wrappers.h
bei -- bei_wrap: d->d                                      -- specfun_wrappers.h
ker -- ker_wrap: d->d                                      -- specfun_wrappers.h
kei -- kei_wrap: d->d                                      -- specfun_wrappers.h
berp -- berp_wrap: d->d                                    -- specfun_wrappers.h
beip -- beip_wrap: d->d                                    -- specfun_wrappers.h
kerp -- kerp_wrap: d->d                                    -- specfun_wrappers.h
keip -- keip_wrap: d->d                                    -- specfun_wrappers.h
zeta -- zeta: dd->d                                        -- cephes.h
kolmogorov -- kolmogorov: d->d                             -- cephes.h
kolmogi -- kolmogi: d->d                                   -- cephes.h
besselpoly -- besselpoly: ddd->d                           -- c_misc/misc.h
btdtria -- cdfbet3_wrap: ddd->d                            -- cdf_wrappers.h
btdtrib -- cdfbet4_wrap: ddd->d                            -- cdf_wrappers.h
bdtrik -- cdfbin2_wrap: ddd->d                             -- cdf_wrappers.h
bdtrin -- cdfbin3_wrap: ddd->d                             -- cdf_wrappers.h
chdtriv -- cdfchi3_wrap: dd->d                             -- cdf_wrappers.h
chndtr -- cdfchn1_wrap: ddd->d                             -- cdf_wrappers.h
chndtrix -- cdfchn2_wrap: ddd->d                           -- cdf_wrappers.h
chndtridf -- cdfchn3_wrap: ddd->d                          -- cdf_wrappers.h
chndtrinc -- cdfchn4_wrap: ddd->d                          -- cdf_wrappers.h
fdtridfd -- cdff4_wrap: ddd->d                             -- cdf_wrappers.h
ncfdtr -- cdffnc1_wrap: dddd->d                            -- cdf_wrappers.h
ncfdtri -- cdffnc2_wrap: dddd->d                           -- cdf_wrappers.h
ncfdtridfn -- cdffnc3_wrap: dddd->d                        -- cdf_wrappers.h
ncfdtridfd -- cdffnc4_wrap: dddd->d                        -- cdf_wrappers.h
ncfdtrinc -- cdffnc5_wrap: dddd->d                         -- cdf_wrappers.h
gdtrix -- cdfgam2_wrap: ddd->d                             -- cdf_wrappers.h
gdtrib -- cdfgam3_wrap: ddd->d                             -- cdf_wrappers.h
gdtria -- cdfgam4_wrap: ddd->d                             -- cdf_wrappers.h
nbdtrik -- cdfnbn2_wrap: ddd->d                            -- cdf_wrappers.h
nbdtrin -- cdfnbn3_wrap: ddd->d                            -- cdf_wrappers.h
nrdtrimn -- cdfnor3_wrap: ddd->d                           -- cdf_wrappers.h
nrdtrisd -- cdfnor4_wrap: ddd->d                           -- cdf_wrappers.h
pdtrik -- cdfpoi2_wrap: dd->d                              -- cdf_wrappers.h
stdtr -- cdft1_wrap: dd->d                                 -- cdf_wrappers.h
stdtrit -- cdft2_wrap: dd->d                               -- cdf_wrappers.h
stdtridf -- cdft3_wrap: dd->d                              -- cdf_wrappers.h
nctdtr -- cdftnc1_wrap: ddd->d                             -- cdf_wrappers.h
nctdtrit -- cdftnc2_wrap: ddd->d                           -- cdf_wrappers.h
nctdtridf -- cdftnc3_wrap: ddd->d                          -- cdf_wrappers.h
nctdtrinc -- cdftnc4_wrap: ddd->d                          -- cdf_wrappers.h
tklmbda -- tukeylambdacdf: dd->d                           -- cdf_wrappers.h
mathieu_a -- cem_cva_wrap: dd->d                           -- specfun_wrappers.h
mathieu_b -- sem_cva_wrap: dd->d                           -- specfun_wrappers.h
mathieu_cem -- cem_wrap: ddd*dd->*i                        -- specfun_wrappers.h
mathieu_sem -- sem_wrap: ddd*dd->*i                        -- specfun_wrappers.h
mathieu_modcem1 -- mcm1_wrap: ddd*dd->*i                   -- specfun_wrappers.h
mathieu_modcem2 -- mcm2_wrap: ddd*dd->*i                   -- specfun_wrappers.h
mathieu_modsem1 -- msm1_wrap: ddd*dd->*i                   -- specfun_wrappers.h
mathieu_modsem2 -- msm2_wrap: ddd*dd->*i                   -- specfun_wrappers.h
lpmv -- pmv_wrap: ddd->d                                   -- specfun_wrappers.h
pbwa -- pbwa_wrap: dd*dd->*i                               -- specfun_wrappers.h
pbdv -- pbdv_wrap: dd*dd->*i                               -- specfun_wrappers.h
pbvv -- pbvv_wrap: dd*dd->*i                               -- specfun_wrappers.h
pro_cv -- prolate_segv_wrap: ddd->d                        -- specfun_wrappers.h
obl_cv -- oblate_segv_wrap: ddd->d                         -- specfun_wrappers.h
pro_ang1_cv -- prolate_aswfa_wrap: ddddd*dd->*i            -- specfun_wrappers.h
pro_rad1_cv -- prolate_radial1_wrap: ddddd*dd->*i          -- specfun_wrappers.h
pro_rad2_cv -- prolate_radial2_wrap: ddddd*dd->*i          -- specfun_wrappers.h
obl_ang1_cv -- oblate_aswfa_wrap: ddddd*dd->*i             -- specfun_wrappers.h
obl_rad1_cv -- oblate_radial1_wrap: ddddd*dd->*i           -- specfun_wrappers.h
obl_rad2_cv -- oblate_radial2_wrap: ddddd*dd->*i           -- specfun_wrappers.h
pro_ang1 -- prolate_aswfa_nocv_wrap: dddd*d->d             -- specfun_wrappers.h
pro_rad1 -- prolate_radial1_nocv_wrap: dddd*d->d           -- specfun_wrappers.h
pro_rad2 -- prolate_radial2_nocv_wrap: dddd*d->d           -- specfun_wrappers.h
obl_ang1 -- oblate_aswfa_nocv_wrap: dddd*d->d              -- specfun_wrappers.h
obl_rad1 -- oblate_radial1_nocv_wrap: dddd*d->d            -- specfun_wrappers.h
obl_rad2 -- oblate_radial2_nocv_wrap: dddd*d->d            -- specfun_wrappers.h
modfresnelp -- modified_fresnel_plus_wrap: d*DD->*i        -- specfun_wrappers.h
modfresnelm -- modified_fresnel_minus_wrap: d*DD->*i       -- specfun_wrappers.h
"""

# Ufuncs with C++
UFUNCS_CXX = """
wofz -- faddeeva_w: D->D                                    -- _faddeeva.h
erfc -- erfc: d->d, faddeeva_erfc: D->D                     -- cephes.h, _faddeeva.h
erf -- erf: d->d, faddeeva_erf: D->D                        -- cephes.h, _faddeeva.h
dawsn -- faddeeva_dawsn: d->d, faddeeva_dawsn_complex: D->D -- _faddeeva.h
erfcx -- faddeeva_erfcx: d->d, faddeeva_erfcx_complex: D->D -- _faddeeva.h
erfi -- faddeeva_erfi: d->d, faddeeva_erfi_complex: D->D    -- _faddeeva.h
"""

#---------------------------------------------------------------------------------
# Extra code
#---------------------------------------------------------------------------------

EXTRA_CODE_COMMON = """
#
# Error handling system
#

cimport sf_error

cdef extern from "numpy/ufuncobject.h":
    int PyUFunc_getfperr() nogil

cdef public int wrap_PyUFunc_getfperr() nogil:
    \"\"\"
    Call PyUFunc_getfperr in a context where PyUFunc_API array is initialized;
    this avoids messing with the UNIQUE_SYMBOL #defines
    \"\"\"
    return PyUFunc_getfperr()

def _errprint(inflag=None):
    \"\"\"
    errprint(flag=None)

    Sets or returns the error printing flag for special functions.

    Parameters
    ----------
    flag : bool, optional
        Whether warnings concerning evaluation of special functions in
        scipy.special are shown. If omitted, no change is made to the
        current setting.

    Returns
    -------
    old_flag
        Previous value of the error flag

    \"\"\"
    if inflag is not None:
        return sf_error.set_print(int(bool(inflag)))
    else:
        return sf_error.get_print()

"""

EXTRA_CODE = EXTRA_CODE_COMMON + """
#
# Aliases
#

jn = jv
"""

EXTRA_CODE_CXX = EXTRA_CODE_COMMON + """
"""



#---------------------------------------------------------------------------------
# Code generation
#---------------------------------------------------------------------------------

import os
import subprocess
import optparse
import re
import textwrap

add_newdocs = __import__('add_newdocs')

CY_TYPES = {
    'f': 'float',
    'd': 'double',
    'g': 'long double',
    'F': 'float complex',
    'D': 'double complex',
    'G': 'long double complex',
    'i': 'int',
    'l': 'long',
    'v': 'void',
}

C_TYPES = {
    'f': 'npy_float',
    'd': 'npy_double',
    'g': 'npy_longdouble',
    'F': 'npy_cfloat',
    'D': 'npy_cdouble',
    'G': 'npy_clongdouble',
    'i': 'npy_int',
    'l': 'npy_long',
    'v': 'void',
}

TYPE_NAMES = {
    'f': 'NPY_FLOAT',
    'd': 'NPY_DOUBLE',
    'g': 'NPY_LONGDOUBLE',
    'F': 'NPY_CFLOAT',
    'D': 'NPY_CDOUBLE',
    'G': 'NPY_CLONGDOUBLE',
    'i': 'NPY_INT',
    'l': 'NPY_LONG',
}

def cast_order(c):
    return ['ilfdgFDG'.index(x) for x in c]

# These downcasts will cause the function to return NaNs, unless the
# values happen to coincide exactly.
DANGEROUS_DOWNCAST = set([
    ('F', 'i'), ('F', 'l'), ('F', 'f'), ('F', 'd'), ('F', 'g'),
    ('D', 'i'), ('D', 'l'), ('D', 'f'), ('D', 'd'), ('D', 'g'),
    ('G', 'i'), ('G', 'l'), ('G', 'f'), ('G', 'd'), ('G', 'g'),
    ('f', 'i'), ('f', 'l'),
    ('d', 'i'), ('d', 'l'),
    ('g', 'i'), ('g', 'l'),
    ('l', 'i'),
])

NAN_VALUE = {
    'f': 'NPY_NAN',
    'd': 'NPY_NAN',
    'g': 'NPY_NAN',
    'F': 'NPY_NAN',
    'D': 'NPY_NAN',
    'G': 'NPY_NAN',
    'i': '0xbad0bad0',
    'l': '0xbad0bad0',
}

def generate_loop(func_inputs, func_outputs, func_retval,
                  ufunc_inputs, ufunc_outputs):
    """
    Generate a UFunc loop function that calls a function given as its
    data parameter with the specified input and output arguments and
    return value.

    This function can be passed to PyUFunc_FromFuncAndData.

    Parameters
    ----------
    func_inputs, func_outputs, func_retval : str
        Signature of the function to call, given as type codes of the
        input, output and return value arguments. These 1-character
        codes are given according to the CY_TYPES and TYPE_NAMES
        lists above.

        The corresponding C function signature to be called is:

            retval func(intype1 iv1, intype2 iv2, ..., outtype1 *ov1, ...);

        If len(ufunc_outputs) == len(func_outputs)+1, the return value
        is treated as the first output argument. Otherwise, the return
        value is ignored.

    ufunc_inputs, ufunc_outputs : str
        Ufunc input and output signature.

        This does not have to exactly match the function signature,
        as long as the type casts work out on the C level.

    Returns
    -------
    loop_name
        Name of the generated loop function.
    loop_body
        Generated C code for the loop.

    """
    if len(func_inputs) != len(ufunc_inputs):
        raise ValueError("Function and ufunc have different number of inputs")

    if len(func_outputs) != len(ufunc_outputs) and not (
            func_retval != "v" and len(func_outputs)+1 == len(ufunc_outputs)):
        raise ValueError("Function retval and ufunc outputs don't match")

    name = "loop_%s_%s_%s_As_%s_%s" % (
        func_retval, func_inputs, func_outputs, ufunc_inputs, ufunc_outputs
        )
    body = "cdef void %s(char **args, np.npy_intp *dims, np.npy_intp *steps, void *data) nogil:\n" % name
    body += "    cdef np.npy_intp i, n = dims[0]\n"
    body += "    cdef void *func = (<void**>data)[0]\n"
    body += "    cdef char *func_name = <char*>(<void**>data)[1]\n"

    pointers = []
    for j in range(len(ufunc_inputs)):
        pointers.append("*ip%d = args[%d]" % (j, j))
    for j in range(len(ufunc_outputs)):
        pointers.append("*op%d = args[%d]" % (j, j + len(ufunc_inputs)))
    body += "    cdef char %s\n" % ", ".join(pointers)

    ftypes = []
    fvars = []
    outtypecodes = []
    for j in range(len(func_inputs)):
        ftypes.append(CY_TYPES[func_inputs[j]])
        fvars.append("<%s>(<%s*>ip%d)[0]" % (
            CY_TYPES[func_inputs[j]],
            CY_TYPES[ufunc_inputs[j]], j))

    if len(func_outputs)+1 == len(ufunc_outputs):
        func_joff = 1
        outtypecodes.append(func_retval)
        body += "    cdef %s ov0\n" % (CY_TYPES[func_retval],)
    else:
        func_joff = 0

    for j, outtype in enumerate(func_outputs):
        body += "    cdef %s ov%d\n" % (CY_TYPES[outtype], j+func_joff)
        ftypes.append("%s *" % CY_TYPES[outtype])
        fvars.append("&ov%d" % (j+func_joff))
        outtypecodes.append(outtype)

    body += "    for i in range(n):\n"
    if len(func_outputs)+1 == len(ufunc_outputs):
        rv = "ov0 = "
    else:
        rv = ""

    funcall = "        %s(<%s(*)(%s) nogil>func)(%s)\n" % (
        rv, CY_TYPES[func_retval], ", ".join(ftypes), ", ".join(fvars))

    # Cast-check inputs and call function
    input_checks = []
    for j in range(len(func_inputs)):
        if (ufunc_inputs[j], func_inputs[j]) in DANGEROUS_DOWNCAST:
            chk = "<%s>(<%s*>ip%d)[0] == (<%s*>ip%d)[0]" % (
                CY_TYPES[func_inputs[j]], CY_TYPES[ufunc_inputs[j]], j,
                CY_TYPES[ufunc_inputs[j]], j)
            input_checks.append(chk)

    if input_checks:
        body += "        if %s:\n" % (" and ".join(input_checks))
        body += "    " + funcall
        body += "        else:\n"
        body += "            sf_error.error(func_name, sf_error.DOMAIN, \"invalid input argument\")\n"
        for j, outtype in enumerate(outtypecodes):
            body += "            ov%d = <%s>%s\n" % (
                j, CY_TYPES[outtype], NAN_VALUE[outtype])
    else:
        body += funcall

    # Assign and cast-check output values
    for j, (outtype, fouttype) in enumerate(zip(ufunc_outputs, outtypecodes)):
        if (fouttype, outtype) in DANGEROUS_DOWNCAST:
            body += "        if ov%d == <%s>ov%d:\n" % (j, CY_TYPES[outtype], j)
            body += "            (<%s *>op%d)[0] = <%s>ov%d\n" % (
                CY_TYPES[outtype], j, CY_TYPES[outtype], j)
            body += "        else:\n"
            body += "            sf_error.error(func_name, sf_error.DOMAIN, \"invalid output\")\n"
            body += "            (<%s *>op%d)[0] = <%s>%s\n" % (
                CY_TYPES[outtype], j, CY_TYPES[outtype], NAN_VALUE[outtype])
        else:
            body += "        (<%s *>op%d)[0] = <%s>ov%d\n" % (
                CY_TYPES[outtype], j, CY_TYPES[outtype], j)
    for j in range(len(ufunc_inputs)):
        body += "        ip%d += steps[%d]\n" % (j, j)
    for j in range(len(ufunc_outputs)):
        body += "        op%d += steps[%d]\n" % (j, j + len(ufunc_inputs))

    body += "    sf_error.check_fpe(func_name)\n"

    return name, body

def iter_variants(inputs, outputs):
    """
    Generate variants of UFunc signatures, by changing variable types,
    within the limitation that the corresponding C types casts still
    work out.

    This does not generate all possibilities, just the ones required
    for the ufunc to work properly with the most common data types.

    Parameters
    ----------
    inputs, outputs : str
        UFunc input and output signature strings

    Yields
    ------
    new_input, new_output : str
        Modified input and output strings.
        Also the original input/output pair is yielded.

    """
    maps = [
        # always use long instead of int (more common type on 64-bit)
        ('i', 'l'),
    ]

    # float32-preserving signatures
    maps = maps + [(a + 'dD', b + 'fF') for a, b in maps]

    # do the replacements
    for src, dst in maps:
        new_inputs = inputs
        new_outputs = outputs
        for a, b in zip(src, dst):
            new_inputs = new_inputs.replace(a, b)
            new_outputs = new_outputs.replace(a, b)
        yield new_inputs, new_outputs

class Ufunc(object):
    """
    Ufunc signature, restricted format suitable for special functions.

    Parameters
    ----------
    name
        Name of the ufunc to create
    signature
        String of form 'func: fff*ff->f, func2: ddd->*i' describing
        the C-level functions and types of their input arguments
        and return values.

        The syntax is 'function_name: inputparams*outputparams->output_retval*ignored_retval'

    """
    def __init__(self, name, signatures):
        self.name = name
        self.signatures = self._parse_signatures(signatures)
        self.doc = add_newdocs.get("scipy.special." + name)
        if self.doc is None:
            raise ValueError("No docstring for ufunc %r" % name)
        self.doc = textwrap.dedent(self.doc).strip()

    def _parse_signatures(self, sigs):
        return [self._parse_signature(x) for x in sigs.split(",")
                if x.strip()]

    def _parse_signature(self, sig):
        m = re.match("\s*(.*):\s*([fdgFDGil]*)\s*\\*\s*([fdgFDGil]*)\s*->\s*([*fdgFDGil]*)\s*$", sig)
        if m:
            func, inarg, outarg, ret = [x.strip() for x in m.groups()]
            if ret.count('*') > 1:
                raise ValueError("%s: Invalid signature: %r" % (self.name, sig))
            return (func, inarg, outarg, ret)
        m = re.match("\s*(.*):\s*([fdgFDGil]*)\s*->\s*([fdgFDGil]?)\s*$", sig)
        if m:
            func, inarg, ret = [x.strip() for x in m.groups()]
            return (func, inarg, "", ret)
        raise ValueError("%s: Invalid signature: %r" % (self.name, sig))

    def _get_signatures_and_loops(self, all_loops):
        inarg_num = None
        outarg_num = None

        seen = set()
        variants = []

        def add_variant(func_name, inarg, outarg, ret, inp, outp):
            if inp in seen:
                return
            seen.add(inp)

            sig = (func_name, inp, outp)
            if "v" in outp:
                raise ValueError("%s: void signature %r" % (self.name, sig))
            if len(inp) != inarg_num or len(outp) != outarg_num:
                raise ValueError("%s: signature %r does not have %d/%d input/output args" % (
                    self.name, sig,
                    inarg_num, outarg_num))

            loop_name, loop = generate_loop(inarg, outarg, ret, inp, outp)
            all_loops[loop_name] = loop
            variants.append((func_name, loop_name, inp, outp))

        # First add base variants
        for func_name, inarg, outarg, ret in self.signatures:
            outp = re.sub(r'\*.*', '', ret) + outarg
            ret = ret.replace('*', '')
            if inarg_num is None:
                inarg_num = len(inarg)
                outarg_num = len(outp)

            inp, outp = list(iter_variants(inarg, outp))[0]
            add_variant(func_name, inarg, outarg, ret, inp, outp)

        # Then the supplementary ones
        for func_name, inarg, outarg, ret in self.signatures:
            outp = re.sub(r'\*.*', '', ret) + outarg
            ret = ret.replace('*', '')
            for inp, outp in iter_variants(inarg, outp):
                add_variant(func_name, inarg, outarg, ret, inp, outp)

        # Then sort variants to input argument cast order
        # -- the sort is stable, so functions earlier in the signature list
        #    are still preferred
        variants.sort(key=lambda v: cast_order(v[2]))

        return variants, inarg_num, outarg_num

    def cython_func_name(self, c_name, specialized=False, prefix="_func_"):
        # support fused types
        m = re.match(r'^(.*?)(\[.*\])$', c_name)
        if m:
            c_base_name, fused_part = m.groups()
        else:
            c_base_name, fused_part = c_name, ""
        if specialized:
            return "%s%s%s" % (prefix, c_base_name, fused_part.replace(' ', '_'))
        else:
            return "%s%s" % (prefix, c_base_name,)

    def get_prototypes(self):
        prototypes = []
        for func_name, inarg, outarg, ret in self.signatures:
            ret = ret.replace('*', '')
            c_args = ([C_TYPES[x] for x in inarg]
                      + [C_TYPES[x] + ' *' for x in outarg])
            cy_args = ([CY_TYPES[x] for x in inarg]
                       + [CY_TYPES[x] + ' *' for x in outarg])
            c_proto = "%s (*)(%s)" % (C_TYPES[ret], ", ".join(c_args))
            cy_proto = "%s (*)(%s) nogil" % (CY_TYPES[ret], ", ".join(cy_args))
            prototypes.append((func_name, c_proto, cy_proto))
        return prototypes

    def generate(self, all_loops):
        toplevel = ""

        variants, inarg_num, outarg_num = self._get_signatures_and_loops(all_loops)

        loops = []
        datas = []
        types = []

        for func_name, loop_name, inputs, outputs in variants:
            for x in inputs:
                types.append(TYPE_NAMES[x])
            for x in outputs:
                types.append(TYPE_NAMES[x])
            loops.append(loop_name)
            datas.append(func_name)

        toplevel += "cdef np.PyUFuncGenericFunction ufunc_%s_loops[%d]\n" % (self.name, len(loops))
        toplevel += "cdef void *ufunc_%s_ptr[%d]\n" % (self.name, 2*len(datas))
        toplevel += "cdef void *ufunc_%s_data[%d]\n" % (self.name, len(datas))
        toplevel += "cdef char ufunc_%s_types[%d]\n" % (self.name, len(types))
        toplevel += 'cdef char *ufunc_%s_doc = (\n    "%s")\n' % (
            self.name,
            self.doc.replace('"', '\\"').replace('\n', '\\n\"\n    "')
            )

        for j, function in enumerate(loops):
            toplevel += "ufunc_%s_loops[%d] = <np.PyUFuncGenericFunction>%s\n" % (self.name, j, function)
        for j, type in enumerate(types):
            toplevel += "ufunc_%s_types[%d] = <char>%s\n" % (self.name, j, type)
        for j, data in enumerate(datas):
            toplevel += "ufunc_%s_ptr[2*%d] = <void*>%s\n" % (self.name, j,
                                                              self.cython_func_name(data, specialized=True))
            toplevel += "ufunc_%s_ptr[2*%d+1] = <void*>(<char*>\"%s\")\n" % (self.name, j,
                                                                             self.name)
        for j, data in enumerate(datas):
            toplevel += "ufunc_%s_data[%d] = &ufunc_%s_ptr[2*%d]\n" % (
                self.name, j, self.name, j)

        toplevel += ('@ = np.PyUFunc_FromFuncAndData(ufunc_@_loops, '
                     'ufunc_@_data, ufunc_@_types, %d, %d, %d, 0, '
                     '"@", ufunc_@_doc, 0)\n' % (len(types)/(inarg_num+outarg_num),
                                                 inarg_num, outarg_num)
                     ).replace('@', self.name)

        return toplevel

def generate(filename, ufunc_str, extra_code):
    proto_h_filename = os.path.splitext(filename)[0] + '_defs.h'
    proto_h_basename = os.path.basename(proto_h_filename)

    ufuncs = []
    headers = {}

    lines = ufunc_str.splitlines()
    lines.sort()

    for line in lines:
        line = line.strip()
        if not line:
            continue
        m = re.match("^([a-z0-9_]+)\s*--\s*(.*?)\s*(--.*)?$", line)
        if not m:
            raise ValueError("Unparseable line %r" % line)
        ufuncs.append(Ufunc(m.group(1), m.group(2)))
        if m.group(3):
            headers[ufuncs[-1].name] = [x.strip() for x in m.group(3)[2:].split(",")]

    toplevel = ""
    defs = ""
    defs_h = []
    all_loops = {}

    ufuncs.sort(key=lambda u: u.name)
    for ufunc in ufuncs:
        t = ufunc.generate(all_loops)
        toplevel += t + "\n"

        cfuncs = ufunc.get_prototypes()

        hdrs = headers.get(ufunc.name, ['cephes.h'])
        if len(hdrs) == 1:
            hdrs = [hdrs[0]] * len(cfuncs)
        elif len(hdrs) != len(cfuncs):
            raise ValueError("%s: wrong number of headers" % ufunc.name)

        for (c_name, c_proto, cy_proto), header in zip(cfuncs, hdrs):
            if header.endswith('.pxd'):
                defs += "from %s cimport %s as %s\n" % (header[:-4],
                                                        ufunc.cython_func_name(c_name,
                                                                               prefix=""),
                                                        ufunc.cython_func_name(c_name))

                # check function signature at compile time
                var_name = c_name.replace('[', '_').replace(']', '_').replace(' ', '_')
                proto_name = '_proto_%s_t' % var_name
                defs += "ctypedef %s\n" % (cy_proto.replace('(*)', proto_name))
                defs += "cdef %s *%s_var = &%s\n" % (
                    proto_name, proto_name, ufunc.cython_func_name(c_name, specialized=True))
            else:
                # redeclare the function, so that the assumed
                # signature is checked at compile time
                new_name = "%s \"%s\"" % (ufunc.cython_func_name(c_name), c_name)
                defs += "cdef extern from \"%s\":\n" % proto_h_filename
                defs += "    cdef %s\n" % (cy_proto.replace('(*)', new_name))
                defs_h.append("#include \"%s\"" % header)
                defs_h.append("%s;" % (c_proto.replace('(*)', c_name)))

    toplevel = "\n".join(list(all_loops.values()) + [defs, toplevel])

    f = open(filename, 'wb')
    f.write("""\
# This file is automatically generated by generate_ufuncs.py.
# Do not edit manually!

cdef extern from "_complexstuff.h":
    # numpy/npy_math.h doesn't have correct extern "C" declarations,
    # so we must include a wrapped version first
    pass

cdef extern from "numpy/npy_math.h":
    double NPY_NAN

cimport numpy as np
from numpy cimport (
    npy_float, npy_double, npy_longdouble,
    npy_cfloat, npy_cdouble, npy_clongdouble,
    npy_int, npy_long,
    NPY_FLOAT, NPY_DOUBLE, NPY_LONGDOUBLE,
    NPY_CFLOAT, NPY_CDOUBLE, NPY_CLONGDOUBLE,
    NPY_INT, NPY_LONG)

ctypedef double complex double_complex

cimport libc

np.import_array()
np.import_ufunc()

""")

    f.write(toplevel)

    f.write(extra_code)

    f.close()

    defs_h = unique(defs_h)
    f = open(proto_h_filename, 'wb')
    f.write("#ifndef UFUNCS_PROTO_H\n#define UFUNCS_PROTO_H 1\n")
    f.write("\n".join(defs_h))
    f.write("\n#endif\n")
    f.close()

def unique(lst):
    """
    Return a list without repeated entries (first occurrence is kept),
    preserving order.
    """
    seen = set()
    new_lst = []
    for item in lst:
        if item in seen:
            continue
        seen.add(item)
        new_lst.append(item)
    return new_lst

def main():
    p = optparse.OptionParser(usage=__doc__.strip())
    options, args = p.parse_args()
    if len(args) != 0:
        p.error('invalid number of arguments')

    generate("_ufuncs.pyx", UFUNCS, EXTRA_CODE)
    generate("_ufuncs_cxx.pyx", UFUNCS_CXX, EXTRA_CODE_CXX)

    subprocess.call(['cython', '_ufuncs.pyx'])
    subprocess.call(['cython', '--cplus', '-o', '_ufuncs_cxx.cxx',
                     '_ufuncs_cxx.pyx'])

    # Strip comments
    for fn in ['_ufuncs.c', '_ufuncs_cxx.cxx']:
        f = open(fn, 'r')
        text = f.read()
        f.close()

        r = re.compile(r'/\*(.*?)\*/', re.S)

        text = r.sub('', text)
        f = open(fn, 'w')
        f.write(text)
        f.close()

if __name__ == "__main__":
    main()
