#!/usr/bin/env python3
#
# This file is part of the MicroPython project, http://micropython.org/
#
# The MIT License (MIT)
#
# Copyright (c) 2016-2019 Damien P. George
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

# Python 2/3 compatibility code
from __future__ import print_function
import platform

if platform.python_version_tuple()[0] == "2":
    str_cons = lambda val, enc=None: val
    bytes_cons = lambda val, enc=None: bytearray(val)
    is_str_type = lambda o: type(o) is str
    is_bytes_type = lambda o: type(o) is bytearray
    is_int_type = lambda o: type(o) is int or type(o) is long
else:
    str_cons = str
    bytes_cons = bytes
    is_str_type = lambda o: type(o) is str
    is_bytes_type = lambda o: type(o) is bytes
    is_int_type = lambda o: type(o) is int
# end compatibility code

import sys
import struct
from collections import namedtuple

sys.path.append(sys.path[0] + "/../py")
import makeqstrdata as qstrutil


class FreezeError(Exception):
    def __init__(self, rawcode, msg):
        self.rawcode = rawcode
        self.msg = msg

    def __str__(self):
        return "error while freezing %s: %s" % (self.rawcode.source_file, self.msg)


class Config:
    MPY_VERSION = 5
    MICROPY_LONGINT_IMPL_NONE = 0
    MICROPY_LONGINT_IMPL_LONGLONG = 1
    MICROPY_LONGINT_IMPL_MPZ = 2


config = Config()


class QStrType:
    def __init__(self, str):
        self.str = str
        self.qstr_esc = qstrutil.qstr_escape(self.str)
        self.qstr_id = "MP_QSTR_" + self.qstr_esc


# Initialise global list of qstrs with static qstrs
global_qstrs = [None]  # MP_QSTRnull should never be referenced
for n in qstrutil.static_qstr_list:
    global_qstrs.append(QStrType(n))


class QStrWindow:
    def __init__(self, size):
        self.window = []
        self.size = size

    def push(self, val):
        self.window = [val] + self.window[: self.size - 1]

    def access(self, idx):
        val = self.window[idx]
        self.window = [val] + self.window[:idx] + self.window[idx + 1 :]
        return val


MP_CODE_BYTECODE = 2
MP_CODE_NATIVE_PY = 3
MP_CODE_NATIVE_VIPER = 4
MP_CODE_NATIVE_ASM = 5

MP_NATIVE_ARCH_NONE = 0
MP_NATIVE_ARCH_X86 = 1
MP_NATIVE_ARCH_X64 = 2
MP_NATIVE_ARCH_ARMV6 = 3
MP_NATIVE_ARCH_ARMV6M = 4
MP_NATIVE_ARCH_ARMV7M = 5
MP_NATIVE_ARCH_ARMV7EM = 6
MP_NATIVE_ARCH_ARMV7EMSP = 7
MP_NATIVE_ARCH_ARMV7EMDP = 8
MP_NATIVE_ARCH_XTENSA = 9
MP_NATIVE_ARCH_XTENSAWIN = 10

MP_BC_MASK_EXTRA_BYTE = 0x9E

MP_BC_FORMAT_BYTE = 0
MP_BC_FORMAT_QSTR = 1
MP_BC_FORMAT_VAR_UINT = 2
MP_BC_FORMAT_OFFSET = 3

# extra byte if caching enabled:
MP_BC_LOAD_NAME = 0x11
MP_BC_LOAD_GLOBAL = 0x12
MP_BC_LOAD_ATTR = 0x13
MP_BC_STORE_ATTR = 0x18

# this function mirrors that in py/bc.c
def mp_opcode_format(bytecode, ip, count_var_uint):
    opcode = bytecode[ip]
    ip_start = ip
    f = (0x000003A4 >> (2 * ((opcode) >> 4))) & 3
    if f == MP_BC_FORMAT_QSTR:
        if config.MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE:
            if (
                opcode == MP_BC_LOAD_NAME
                or opcode == MP_BC_LOAD_GLOBAL
                or opcode == MP_BC_LOAD_ATTR
                or opcode == MP_BC_STORE_ATTR
            ):
                ip += 1
        ip += 3
    else:
        extra_byte = (opcode & MP_BC_MASK_EXTRA_BYTE) == 0
        ip += 1
        if f == MP_BC_FORMAT_VAR_UINT:
            if count_var_uint:
                while bytecode[ip] & 0x80 != 0:
                    ip += 1
                ip += 1
        elif f == MP_BC_FORMAT_OFFSET:
            ip += 2
        ip += extra_byte
    return f, ip - ip_start


def read_prelude_sig(read_byte):
    z = read_byte()
    # xSSSSEAA
    S = (z >> 3) & 0xF
    E = (z >> 2) & 0x1
    F = 0
    A = z & 0x3
    K = 0
    D = 0
    n = 0
    while z & 0x80:
        z = read_byte()
        # xFSSKAED
        S |= (z & 0x30) << (2 * n)
        E |= (z & 0x02) << n
        F |= ((z & 0x40) >> 6) << n
        A |= (z & 0x4) << n
        K |= ((z & 0x08) >> 3) << n
        D |= (z & 0x1) << n
        n += 1
    S += 1
    return S, E, F, A, K, D


def read_prelude_size(read_byte):
    I = 0
    C = 0
    n = 0
    while True:
        z = read_byte()
        # xIIIIIIC
        I |= ((z & 0x7E) >> 1) << (6 * n)
        C |= (z & 1) << n
        if not (z & 0x80):
            break
        n += 1
    return I, C


def extract_prelude(bytecode, ip):
    def local_read_byte():
        b = bytecode[ip_ref[0]]
        ip_ref[0] += 1
        return b

    ip_ref = [ip]  # to close over ip in Python 2 and 3
    (
        n_state,
        n_exc_stack,
        scope_flags,
        n_pos_args,
        n_kwonly_args,
        n_def_pos_args,
    ) = read_prelude_sig(local_read_byte)
    n_info, n_cell = read_prelude_size(local_read_byte)
    ip = ip_ref[0]

    ip2 = ip
    ip = ip2 + n_info + n_cell
    # ip now points to first opcode
    # ip2 points to simple_name qstr
    return ip, ip2, (n_state, n_exc_stack, scope_flags, n_pos_args, n_kwonly_args, n_def_pos_args)


class MPFunTable:
    pass


class RawCode(object):
    # a set of all escaped names, to make sure they are unique
    escaped_names = set()

    # convert code kind number to string
    code_kind_str = {
        MP_CODE_BYTECODE: "MP_CODE_BYTECODE",
        MP_CODE_NATIVE_PY: "MP_CODE_NATIVE_PY",
        MP_CODE_NATIVE_VIPER: "MP_CODE_NATIVE_VIPER",
        MP_CODE_NATIVE_ASM: "MP_CODE_NATIVE_ASM",
    }

    def __init__(self, code_kind, bytecode, prelude_offset, qstrs, objs, raw_codes):
        # set core variables
        self.code_kind = code_kind
        self.bytecode = bytecode
        self.prelude_offset = prelude_offset
        self.qstrs = qstrs
        self.objs = objs
        self.raw_codes = raw_codes

        if self.prelude_offset is None:
            # no prelude, assign a dummy simple_name
            self.prelude_offset = 0
            self.simple_name = global_qstrs[1]
        else:
            # extract prelude
            self.ip, self.ip2, self.prelude = extract_prelude(self.bytecode, self.prelude_offset)
            self.simple_name = self._unpack_qstr(self.ip2)
            self.source_file = self._unpack_qstr(self.ip2 + 2)

    def _unpack_qstr(self, ip):
        qst = self.bytecode[ip] | self.bytecode[ip + 1] << 8
        return global_qstrs[qst]

    def dump(self):
        # dump children first
        for rc in self.raw_codes:
            rc.freeze("")
        # TODO

    def freeze_children(self, parent_name):
        self.escaped_name = parent_name + self.simple_name.qstr_esc

        # make sure the escaped name is unique
        i = 2
        while self.escaped_name in RawCode.escaped_names:
            self.escaped_name = parent_name + self.simple_name.qstr_esc + str(i)
            i += 1
        RawCode.escaped_names.add(self.escaped_name)

        # emit children first
        for rc in self.raw_codes:
            rc.freeze(self.escaped_name + "_")

    def freeze_constants(self):
        # generate constant objects
        for i, obj in enumerate(self.objs):
            obj_name = "const_obj_%s_%u" % (self.escaped_name, i)
            if obj is MPFunTable:
                pass
            elif obj is Ellipsis:
                print("#define %s mp_const_ellipsis_obj" % obj_name)
            elif is_str_type(obj) or is_bytes_type(obj):
                if is_str_type(obj):
                    obj = bytes_cons(obj, "utf8")
                    obj_type = "mp_type_str"
                else:
                    obj_type = "mp_type_bytes"
                print(
                    'STATIC const mp_obj_str_t %s = {{&%s}, %u, %u, (const byte*)"%s"};'
                    % (
                        obj_name,
                        obj_type,
                        qstrutil.compute_hash(obj, config.MICROPY_QSTR_BYTES_IN_HASH),
                        len(obj),
                        "".join(("\\x%02x" % b) for b in obj),
                    )
                )
            elif is_int_type(obj):
                if config.MICROPY_LONGINT_IMPL == config.MICROPY_LONGINT_IMPL_NONE:
                    # TODO check if we can actually fit this long-int into a small-int
                    raise FreezeError(self, "target does not support long int")
                elif config.MICROPY_LONGINT_IMPL == config.MICROPY_LONGINT_IMPL_LONGLONG:
                    # TODO
                    raise FreezeError(self, "freezing int to long-long is not implemented")
                elif config.MICROPY_LONGINT_IMPL == config.MICROPY_LONGINT_IMPL_MPZ:
                    neg = 0
                    if obj < 0:
                        obj = -obj
                        neg = 1
                    bits_per_dig = config.MPZ_DIG_SIZE
                    digs = []
                    z = obj
                    while z:
                        digs.append(z & ((1 << bits_per_dig) - 1))
                        z >>= bits_per_dig
                    ndigs = len(digs)
                    digs = ",".join(("%#x" % d) for d in digs)
                    print(
                        "STATIC const mp_obj_int_t %s = {{&mp_type_int}, "
                        "{.neg=%u, .fixed_dig=1, .alloc=%u, .len=%u, .dig=(uint%u_t*)(const uint%u_t[]){%s}}};"
                        % (obj_name, neg, ndigs, ndigs, bits_per_dig, bits_per_dig, digs)
                    )
            elif type(obj) is float:
                print(
                    "#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_B"
                )
                print(
                    "STATIC const mp_obj_float_t %s = {{&mp_type_float}, (mp_float_t)%.16g};"
                    % (obj_name, obj)
                )
                print("#endif")
            elif type(obj) is complex:
                print(
                    "STATIC const mp_obj_complex_t %s = {{&mp_type_complex}, (mp_float_t)%.16g, (mp_float_t)%.16g};"
                    % (obj_name, obj.real, obj.imag)
                )
            else:
                raise FreezeError(self, "freezing of object %r is not implemented" % (obj,))

        # generate constant table, if it has any entries
        const_table_len = len(self.qstrs) + len(self.objs) + len(self.raw_codes)
        if const_table_len:
            print(
                "STATIC const mp_rom_obj_t const_table_data_%s[%u] = {"
                % (self.escaped_name, const_table_len)
            )
            for qst in self.qstrs:
                print("    MP_ROM_QSTR(%s)," % global_qstrs[qst].qstr_id)
            for i in range(len(self.objs)):
                if self.objs[i] is MPFunTable:
                    print("    &mp_fun_table,")
                elif type(self.objs[i]) is float:
                    print(
                        "#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_B"
                    )
                    print("    MP_ROM_PTR(&const_obj_%s_%u)," % (self.escaped_name, i))
                    print("#elif MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C")
                    n = struct.unpack("<I", struct.pack("<f", self.objs[i]))[0]
                    n = ((n & ~0x3) | 2) + 0x80800000
                    print("    (mp_rom_obj_t)(0x%08x)," % (n,))
                    print("#elif MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D")
                    n = struct.unpack("<Q", struct.pack("<d", self.objs[i]))[0]
                    n += 0x8004000000000000
                    print("    (mp_rom_obj_t)(0x%016x)," % (n,))
                    print("#endif")
                else:
                    print("    MP_ROM_PTR(&const_obj_%s_%u)," % (self.escaped_name, i))
            for rc in self.raw_codes:
                print("    MP_ROM_PTR(&raw_code_%s)," % rc.escaped_name)
            print("};")

    def freeze_module(self, qstr_links=(), type_sig=0):
        # generate module
        if self.simple_name.str != "<module>":
            print("STATIC ", end="")
        print("const mp_raw_code_t raw_code_%s = {" % self.escaped_name)
        print("    .kind = %s," % RawCode.code_kind_str[self.code_kind])
        print("    .scope_flags = 0x%02x," % self.prelude[2])
        print("    .n_pos_args = %u," % self.prelude[3])
        print("    .fun_data = fun_data_%s," % self.escaped_name)
        if len(self.qstrs) + len(self.objs) + len(self.raw_codes):
            print("    .const_table = (mp_uint_t*)const_table_data_%s," % self.escaped_name)
        else:
            print("    .const_table = NULL,")
        print("    #if MICROPY_PERSISTENT_CODE_SAVE")
        print("    .fun_data_len = %u," % len(self.bytecode))
        print("    .n_obj = %u," % len(self.objs))
        print("    .n_raw_code = %u," % len(self.raw_codes))
        if self.code_kind == MP_CODE_BYTECODE:
            print("    #if MICROPY_PY_SYS_SETTRACE")
            print("    .prelude = {")
            print("        .n_state = %u," % self.prelude[0])
            print("        .n_exc_stack = %u," % self.prelude[1])
            print("        .scope_flags = %u," % self.prelude[2])
            print("        .n_pos_args = %u," % self.prelude[3])
            print("        .n_kwonly_args = %u," % self.prelude[4])
            print("        .n_def_pos_args = %u," % self.prelude[5])
            print("        .qstr_block_name = %s," % self.simple_name.qstr_id)
            print("        .qstr_source_file = %s," % self.source_file.qstr_id)
            print("        .line_info = fun_data_%s + %u," % (self.escaped_name, 0))  # TODO
            print("        .opcodes = fun_data_%s + %u," % (self.escaped_name, self.ip))
            print("    },")
            print("    .line_of_definition = %u," % 0)  # TODO
            print("    #endif")
        print("    #if MICROPY_EMIT_MACHINE_CODE")
        print("    .prelude_offset = %u," % self.prelude_offset)
        print("    .n_qstr = %u," % len(qstr_links))
        print("    .qstr_link = NULL,")  # TODO
        print("    #endif")
        print("    #endif")
        print("    #if MICROPY_EMIT_MACHINE_CODE")
        print("    .type_sig = %u," % type_sig)
        print("    #endif")
        print("};")


class RawCodeBytecode(RawCode):
    def __init__(self, bytecode, qstrs, objs, raw_codes):
        super(RawCodeBytecode, self).__init__(
            MP_CODE_BYTECODE, bytecode, 0, qstrs, objs, raw_codes
        )

    def freeze(self, parent_name):
        self.freeze_children(parent_name)

        # generate bytecode data
        print()
        print(
            "// frozen bytecode for file %s, scope %s%s"
            % (self.source_file.str, parent_name, self.simple_name.str)
        )
        print("STATIC ", end="")
        if not config.MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE:
            print("const ", end="")
        print("byte fun_data_%s[%u] = {" % (self.escaped_name, len(self.bytecode)))
        print("   ", end="")
        for i in range(self.ip2):
            print(" 0x%02x," % self.bytecode[i], end="")
        print()
        print("   ", self.simple_name.qstr_id, "& 0xff,", self.simple_name.qstr_id, ">> 8,")
        print("   ", self.source_file.qstr_id, "& 0xff,", self.source_file.qstr_id, ">> 8,")
        print("   ", end="")
        for i in range(self.ip2 + 4, self.ip):
            print(" 0x%02x," % self.bytecode[i], end="")
        print()
        ip = self.ip
        while ip < len(self.bytecode):
            f, sz = mp_opcode_format(self.bytecode, ip, True)
            if f == 1:
                qst = self._unpack_qstr(ip + 1).qstr_id
                extra = "" if sz == 3 else " 0x%02x," % self.bytecode[ip + 3]
                print("   ", "0x%02x," % self.bytecode[ip], qst, "& 0xff,", qst, ">> 8,", extra)
            else:
                print("   ", "".join("0x%02x, " % self.bytecode[ip + i] for i in range(sz)))
            ip += sz
        print("};")

        self.freeze_constants()
        self.freeze_module()


class RawCodeNative(RawCode):
    def __init__(
        self,
        code_kind,
        fun_data,
        prelude_offset,
        prelude,
        qstr_links,
        qstrs,
        objs,
        raw_codes,
        type_sig,
    ):
        super(RawCodeNative, self).__init__(
            code_kind, fun_data, prelude_offset, qstrs, objs, raw_codes
        )
        self.prelude = prelude
        self.qstr_links = qstr_links
        self.type_sig = type_sig
        if config.native_arch in (
            MP_NATIVE_ARCH_X86,
            MP_NATIVE_ARCH_X64,
            MP_NATIVE_ARCH_XTENSA,
            MP_NATIVE_ARCH_XTENSAWIN,
        ):
            self.fun_data_attributes = '__attribute__((section(".text,\\"ax\\",@progbits # ")))'
        else:
            self.fun_data_attributes = '__attribute__((section(".text,\\"ax\\",%progbits @ ")))'

        # Allow single-byte alignment by default for x86/x64.
        # ARM needs word alignment, ARM Thumb needs halfword, due to instruction size.
        # Xtensa needs word alignment due to the 32-bit constant table embedded in the code.
        if config.native_arch in (
            MP_NATIVE_ARCH_ARMV6,
            MP_NATIVE_ARCH_XTENSA,
            MP_NATIVE_ARCH_XTENSAWIN,
        ):
            # ARMV6 or Xtensa -- four byte align.
            self.fun_data_attributes += " __attribute__ ((aligned (4)))"
        elif MP_NATIVE_ARCH_ARMV6M <= config.native_arch <= MP_NATIVE_ARCH_ARMV7EMDP:
            # ARMVxxM -- two byte align.
            self.fun_data_attributes += " __attribute__ ((aligned (2)))"

    def _asm_thumb_rewrite_mov(self, pc, val):
        print("    (%u & 0xf0) | (%s >> 12)," % (self.bytecode[pc], val), end="")
        print(" (%u & 0xfb) | (%s >> 9 & 0x04)," % (self.bytecode[pc + 1], val), end="")
        print(" (%s & 0xff)," % (val,), end="")
        print(" (%u & 0x07) | (%s >> 4 & 0x70)," % (self.bytecode[pc + 3], val))

    def _link_qstr(self, pc, kind, qst):
        if kind == 0:
            # Generic 16-bit link
            print("    %s & 0xff, %s >> 8," % (qst, qst))
            return 2
        else:
            # Architecture-specific link
            is_obj = kind == 2
            if is_obj:
                qst = "((uintptr_t)MP_OBJ_NEW_QSTR(%s))" % qst
            if config.native_arch in (
                MP_NATIVE_ARCH_X86,
                MP_NATIVE_ARCH_X64,
                MP_NATIVE_ARCH_XTENSA,
                MP_NATIVE_ARCH_XTENSAWIN,
            ):
                print(
                    "    %s & 0xff, (%s >> 8) & 0xff, (%s >> 16) & 0xff, %s >> 24,"
                    % (qst, qst, qst, qst)
                )
                return 4
            elif MP_NATIVE_ARCH_ARMV6M <= config.native_arch <= MP_NATIVE_ARCH_ARMV7EMDP:
                if is_obj:
                    # qstr object, movw and movt
                    self._asm_thumb_rewrite_mov(pc, qst)
                    self._asm_thumb_rewrite_mov(pc + 4, "(%s >> 16)" % qst)
                    return 8
                else:
                    # qstr number, movw instruction
                    self._asm_thumb_rewrite_mov(pc, qst)
                    return 4
            else:
                assert 0

    def freeze(self, parent_name):
        if self.prelude[2] & ~0x0F:
            raise FreezeError("unable to freeze code with relocations")

        self.freeze_children(parent_name)

        # generate native code data
        print()
        if self.code_kind == MP_CODE_NATIVE_PY:
            print(
                "// frozen native code for file %s, scope %s%s"
                % (self.source_file.str, parent_name, self.simple_name.str)
            )
        elif self.code_kind == MP_CODE_NATIVE_VIPER:
            print("// frozen viper code for scope %s" % (parent_name,))
        else:
            print("// frozen assembler code for scope %s" % (parent_name,))
        print(
            "STATIC const byte fun_data_%s[%u] %s = {"
            % (self.escaped_name, len(self.bytecode), self.fun_data_attributes)
        )

        if self.code_kind == MP_CODE_NATIVE_PY:
            i_top = self.prelude_offset
        else:
            i_top = len(self.bytecode)
        i = 0
        qi = 0
        while i < i_top:
            if qi < len(self.qstr_links) and i == self.qstr_links[qi][0]:
                # link qstr
                qi_off, qi_kind, qi_val = self.qstr_links[qi]
                qst = global_qstrs[qi_val].qstr_id
                i += self._link_qstr(i, qi_kind, qst)
                qi += 1
            else:
                # copy machine code (max 16 bytes)
                i16 = min(i + 16, i_top)
                if qi < len(self.qstr_links):
                    i16 = min(i16, self.qstr_links[qi][0])
                print("   ", end="")
                for ii in range(i, i16):
                    print(" 0x%02x," % self.bytecode[ii], end="")
                print()
                i = i16

        if self.code_kind == MP_CODE_NATIVE_PY:
            print("   ", end="")
            for i in range(self.prelude_offset, self.ip2):
                print(" 0x%02x," % self.bytecode[i], end="")
            print()

            print("   ", self.simple_name.qstr_id, "& 0xff,", self.simple_name.qstr_id, ">> 8,")
            print("   ", self.source_file.qstr_id, "& 0xff,", self.source_file.qstr_id, ">> 8,")

            print("   ", end="")
            for i in range(self.ip2 + 4, self.ip):
                print(" 0x%02x," % self.bytecode[i], end="")
            print()

        print("};")

        self.freeze_constants()
        self.freeze_module(self.qstr_links, self.type_sig)


class BytecodeBuffer:
    def __init__(self, size):
        self.buf = bytearray(size)
        self.idx = 0

    def is_full(self):
        return self.idx == len(self.buf)

    def append(self, b):
        self.buf[self.idx] = b
        self.idx += 1


def read_byte(f, out=None):
    b = bytes_cons(f.read(1))[0]
    if out is not None:
        out.append(b)
    return b


def read_uint(f, out=None):
    i = 0
    while True:
        b = read_byte(f, out)
        i = (i << 7) | (b & 0x7F)
        if b & 0x80 == 0:
            break
    return i


def read_qstr(f, qstr_win):
    ln = read_uint(f)
    if ln == 0:
        # static qstr
        return bytes_cons(f.read(1))[0]
    if ln & 1:
        # qstr in table
        return qstr_win.access(ln >> 1)
    ln >>= 1
    data = str_cons(f.read(ln), "utf8")
    global_qstrs.append(QStrType(data))
    qstr_win.push(len(global_qstrs) - 1)
    return len(global_qstrs) - 1


def read_obj(f):
    obj_type = f.read(1)
    if obj_type == b"e":
        return Ellipsis
    else:
        buf = f.read(read_uint(f))
        if obj_type == b"s":
            return str_cons(buf, "utf8")
        elif obj_type == b"b":
            return bytes_cons(buf)
        elif obj_type == b"i":
            return int(str_cons(buf, "ascii"), 10)
        elif obj_type == b"f":
            return float(str_cons(buf, "ascii"))
        elif obj_type == b"c":
            return complex(str_cons(buf, "ascii"))
        else:
            assert 0


def read_prelude(f, bytecode, qstr_win):
    (
        n_state,
        n_exc_stack,
        scope_flags,
        n_pos_args,
        n_kwonly_args,
        n_def_pos_args,
    ) = read_prelude_sig(lambda: read_byte(f, bytecode))
    n_info, n_cell = read_prelude_size(lambda: read_byte(f, bytecode))
    read_qstr_and_pack(f, bytecode, qstr_win)  # simple_name
    read_qstr_and_pack(f, bytecode, qstr_win)  # source_file
    for _ in range(n_info - 4 + n_cell):
        read_byte(f, bytecode)
    return n_state, n_exc_stack, scope_flags, n_pos_args, n_kwonly_args, n_def_pos_args


def read_qstr_and_pack(f, bytecode, qstr_win):
    qst = read_qstr(f, qstr_win)
    bytecode.append(qst & 0xFF)
    bytecode.append(qst >> 8)


def read_bytecode(file, bytecode, qstr_win):
    while not bytecode.is_full():
        op = read_byte(file, bytecode)
        f, sz = mp_opcode_format(bytecode.buf, bytecode.idx - 1, False)
        sz -= 1
        if f == MP_BC_FORMAT_QSTR:
            read_qstr_and_pack(file, bytecode, qstr_win)
            sz -= 2
        elif f == MP_BC_FORMAT_VAR_UINT:
            while read_byte(file, bytecode) & 0x80:
                pass
        for _ in range(sz):
            read_byte(file, bytecode)


def read_raw_code(f, qstr_win):
    kind_len = read_uint(f)
    kind = (kind_len & 3) + MP_CODE_BYTECODE
    fun_data_len = kind_len >> 2
    fun_data = BytecodeBuffer(fun_data_len)

    if kind == MP_CODE_BYTECODE:
        prelude = read_prelude(f, fun_data, qstr_win)
        read_bytecode(f, fun_data, qstr_win)
    else:
        fun_data.buf[:] = f.read(fun_data_len)

        qstr_links = []
        if kind in (MP_CODE_NATIVE_PY, MP_CODE_NATIVE_VIPER):
            # load qstr link table
            n_qstr_link = read_uint(f)
            for _ in range(n_qstr_link):
                off = read_uint(f)
                qst = read_qstr(f, qstr_win)
                qstr_links.append((off >> 2, off & 3, qst))

        type_sig = 0
        if kind == MP_CODE_NATIVE_PY:
            prelude_offset = read_uint(f)
            _, name_idx, prelude = extract_prelude(fun_data.buf, prelude_offset)
            fun_data.idx = name_idx  # rewind to where qstrs are in prelude
            read_qstr_and_pack(f, fun_data, qstr_win)  # simple_name
            read_qstr_and_pack(f, fun_data, qstr_win)  # source_file
        else:
            prelude_offset = None
            scope_flags = read_uint(f)
            n_pos_args = 0
            if kind == MP_CODE_NATIVE_ASM:
                n_pos_args = read_uint(f)
                type_sig = read_uint(f)
            prelude = (None, None, scope_flags, n_pos_args, 0)

    qstrs = []
    objs = []
    raw_codes = []
    if kind != MP_CODE_NATIVE_ASM:
        # load constant table
        n_obj = read_uint(f)
        n_raw_code = read_uint(f)
        qstrs = [read_qstr(f, qstr_win) for _ in range(prelude[3] + prelude[4])]
        if kind != MP_CODE_BYTECODE:
            objs.append(MPFunTable)
        objs.extend([read_obj(f) for _ in range(n_obj)])
        raw_codes = [read_raw_code(f, qstr_win) for _ in range(n_raw_code)]

    if kind == MP_CODE_BYTECODE:
        return RawCodeBytecode(fun_data.buf, qstrs, objs, raw_codes)
    else:
        return RawCodeNative(
            kind,
            fun_data.buf,
            prelude_offset,
            prelude,
            qstr_links,
            qstrs,
            objs,
            raw_codes,
            type_sig,
        )


def read_mpy(filename):
    with open(filename, "rb") as f:
        header = bytes_cons(f.read(4))
        if header[0] != ord("M"):
            raise Exception("not a valid .mpy file")
        if header[1] != config.MPY_VERSION:
            raise Exception("incompatible .mpy version")
        feature_byte = header[2]
        qw_size = read_uint(f)
        config.MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE = (feature_byte & 1) != 0
        config.MICROPY_PY_BUILTINS_STR_UNICODE = (feature_byte & 2) != 0
        mpy_native_arch = feature_byte >> 2
        if mpy_native_arch != MP_NATIVE_ARCH_NONE:
            if config.native_arch == MP_NATIVE_ARCH_NONE:
                config.native_arch = mpy_native_arch
            elif config.native_arch != mpy_native_arch:
                raise Exception("native architecture mismatch")
        config.mp_small_int_bits = header[3]
        qstr_win = QStrWindow(qw_size)
        rc = read_raw_code(f, qstr_win)
        rc.mpy_source_file = filename
        rc.qstr_win_size = qw_size
        return rc


def dump_mpy(raw_codes):
    for rc in raw_codes:
        rc.dump()


def freeze_mpy(base_qstrs, raw_codes):
    # add to qstrs
    new = {}
    for q in global_qstrs:
        # don't add duplicates
        if q is None or q.qstr_esc in base_qstrs or q.qstr_esc in new:
            continue
        new[q.qstr_esc] = (len(new), q.qstr_esc, q.str)
    new = sorted(new.values(), key=lambda x: x[0])

    print('#include "py/mpconfig.h"')
    print('#include "py/objint.h"')
    print('#include "py/objstr.h"')
    print('#include "py/emitglue.h"')
    print('#include "py/nativeglue.h"')
    print()

    print(
        "#if MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE != %u"
        % config.MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
    )
    print('#error "incompatible MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE"')
    print("#endif")
    print()

    print("#if MICROPY_LONGINT_IMPL != %u" % config.MICROPY_LONGINT_IMPL)
    print('#error "incompatible MICROPY_LONGINT_IMPL"')
    print("#endif")
    print()

    if config.MICROPY_LONGINT_IMPL == config.MICROPY_LONGINT_IMPL_MPZ:
        print("#if MPZ_DIG_SIZE != %u" % config.MPZ_DIG_SIZE)
        print('#error "incompatible MPZ_DIG_SIZE"')
        print("#endif")
        print()

    print("#if MICROPY_PY_BUILTINS_FLOAT")
    print("typedef struct _mp_obj_float_t {")
    print("    mp_obj_base_t base;")
    print("    mp_float_t value;")
    print("} mp_obj_float_t;")
    print("#endif")
    print()

    print("#if MICROPY_PY_BUILTINS_COMPLEX")
    print("typedef struct _mp_obj_complex_t {")
    print("    mp_obj_base_t base;")
    print("    mp_float_t real;")
    print("    mp_float_t imag;")
    print("} mp_obj_complex_t;")
    print("#endif")
    print()

    if len(new) > 0:
        print("enum {")
        for i in range(len(new)):
            if i == 0:
                print("    MP_QSTR_%s = MP_QSTRnumber_of," % new[i][1])
            else:
                print("    MP_QSTR_%s," % new[i][1])
        print("};")

    # As in qstr.c, set so that the first dynamically allocated pool is twice this size; must be <= the len
    qstr_pool_alloc = min(len(new), 10)

    print()
    print("extern const qstr_pool_t mp_qstr_const_pool;")
    print("const qstr_pool_t mp_qstr_frozen_const_pool = {")
    print("    (qstr_pool_t*)&mp_qstr_const_pool, // previous pool")
    print("    MP_QSTRnumber_of, // previous pool size")
    print("    %u, // allocated entries" % qstr_pool_alloc)
    print("    %u, // used entries" % len(new))
    print("    {")
    for _, _, qstr in new:
        print(
            "        %s,"
            % qstrutil.make_bytes(
                config.MICROPY_QSTR_BYTES_IN_LEN, config.MICROPY_QSTR_BYTES_IN_HASH, qstr
            )
        )
    print("    },")
    print("};")

    for rc in raw_codes:
        rc.freeze(rc.source_file.str.replace("/", "_")[:-3] + "_")

    print()
    print("const char mp_frozen_mpy_names[] = {")
    for rc in raw_codes:
        module_name = rc.source_file.str
        print('"%s\\0"' % module_name)
    print('"\\0"};')

    print("const mp_raw_code_t *const mp_frozen_mpy_content[] = {")
    for rc in raw_codes:
        print("    &raw_code_%s," % rc.escaped_name)
    print("};")


def merge_mpy(raw_codes, output_file):
    assert len(raw_codes) <= 31  # so var-uints all fit in 1 byte
    merged_mpy = bytearray()

    if len(raw_codes) == 1:
        with open(raw_codes[0].mpy_source_file, "rb") as f:
            merged_mpy.extend(f.read())
    else:
        header = bytearray(5)
        header[0] = ord("M")
        header[1] = config.MPY_VERSION
        header[2] = (
            config.native_arch << 2
            | config.MICROPY_PY_BUILTINS_STR_UNICODE << 1
            | config.MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
        )
        header[3] = config.mp_small_int_bits
        header[4] = 32  # qstr_win_size
        merged_mpy.extend(header)

        bytecode = bytearray()
        bytecode_len = 6 + len(raw_codes) * 4 + 2
        bytecode.append(bytecode_len << 2)  # kind and length
        bytecode.append(0b00000000)  # signature prelude
        bytecode.append(0b00001000)  # size prelude
        bytecode.extend(b"\x00\x01")  # MP_QSTR_
        bytecode.extend(b"\x00\x01")  # MP_QSTR_
        for idx in range(len(raw_codes)):
            bytecode.append(0x32)  # MP_BC_MAKE_FUNCTION
            bytecode.append(idx)  # index raw code
            bytecode.extend(b"\x34\x00")  # MP_BC_CALL_FUNCTION, 0 args
        bytecode.extend(b"\x51\x63")  # MP_BC_LOAD_NONE, MP_BC_RETURN_VALUE

        bytecode.append(0)  # n_obj
        bytecode.append(len(raw_codes))  # n_raw_code

        merged_mpy.extend(bytecode)

        for rc in raw_codes:
            with open(rc.mpy_source_file, "rb") as f:
                f.read(4)  # skip header
                read_uint(f)  # skip qstr_win_size
                data = f.read()  # read rest of mpy file
                merged_mpy.extend(data)

    if output_file is None:
        sys.stdout.buffer.write(merged_mpy)
    else:
        with open(output_file, "wb") as f:
            f.write(merged_mpy)


def main():
    import argparse

    cmd_parser = argparse.ArgumentParser(description="A tool to work with MicroPython .mpy files.")
    cmd_parser.add_argument("-d", "--dump", action="store_true", help="dump contents of files")
    cmd_parser.add_argument("-f", "--freeze", action="store_true", help="freeze files")
    cmd_parser.add_argument(
        "--merge", action="store_true", help="merge multiple .mpy files into one"
    )
    cmd_parser.add_argument("-q", "--qstr-header", help="qstr header file to freeze against")
    cmd_parser.add_argument(
        "-mlongint-impl",
        choices=["none", "longlong", "mpz"],
        default="mpz",
        help="long-int implementation used by target (default mpz)",
    )
    cmd_parser.add_argument(
        "-mmpz-dig-size",
        metavar="N",
        type=int,
        default=16,
        help="mpz digit size used by target (default 16)",
    )
    cmd_parser.add_argument("-o", "--output", default=None, help="output file")
    cmd_parser.add_argument("files", nargs="+", help="input .mpy files")
    args = cmd_parser.parse_args()

    # set config values relevant to target machine
    config.MICROPY_LONGINT_IMPL = {
        "none": config.MICROPY_LONGINT_IMPL_NONE,
        "longlong": config.MICROPY_LONGINT_IMPL_LONGLONG,
        "mpz": config.MICROPY_LONGINT_IMPL_MPZ,
    }[args.mlongint_impl]
    config.MPZ_DIG_SIZE = args.mmpz_dig_size
    config.native_arch = MP_NATIVE_ARCH_NONE

    # set config values for qstrs, and get the existing base set of qstrs
    if args.qstr_header:
        qcfgs, base_qstrs = qstrutil.parse_input_headers([args.qstr_header])
        config.MICROPY_QSTR_BYTES_IN_LEN = int(qcfgs["BYTES_IN_LEN"])
        config.MICROPY_QSTR_BYTES_IN_HASH = int(qcfgs["BYTES_IN_HASH"])
    else:
        config.MICROPY_QSTR_BYTES_IN_LEN = 1
        config.MICROPY_QSTR_BYTES_IN_HASH = 1
        base_qstrs = {}

    raw_codes = [read_mpy(file) for file in args.files]

    if args.dump:
        dump_mpy(raw_codes)
    elif args.freeze:
        try:
            freeze_mpy(base_qstrs, raw_codes)
        except FreezeError as er:
            print(er, file=sys.stderr)
            sys.exit(1)
    elif args.merge:
        merged_mpy = merge_mpy(raw_codes, args.output)


if __name__ == "__main__":
    main()
