diff --git a/doltool/doltool.py b/doltool/doltool.py
new file mode 100644
index 0000000..cfd2c89
--- /dev/null
+++ b/doltool/doltool.py
@@ -0,0 +1,254 @@
+from pathlib import Path
+import logging
+import re
+
+
+__version__ = "0.0.3"
+__author__ = "algoflash"
+__license__ = "MIT"
+__status__ = "developpement"
+
+
+class InvalidIniFileEntryError(Exception): pass
+class InvalidImgOffsetError(Exception): pass
+class InvalidVirtualAddressError(Exception): pass
+
+
+# Get non-overlapping intervals from interval by removing intervals_to_remove
+# intervals_to_remove has to be sorted by left val
+# return [[a,b], ...] or None
+def remove_intervals_from_interval(interval:list, intervals_to_remove:list):
+    interval = interval[:]
+    result_intervals = []
+    for interval_to_remove in intervals_to_remove:
+        if interval_to_remove[2] < interval[1]: continue # end before
+        if interval_to_remove[1] > interval[2]: break # begin after
+
+        if interval_to_remove[1] <= interval[1]: # begin before
+            if interval_to_remove[2] >= interval[2]: # total overlap
+                return None
+            interval[1] = interval_to_remove[2] # begin truncate
+        elif interval_to_remove[2] >= interval[2]: # end truncate
+            interval[2] = interval_to_remove[1]
+            break
+        else: # middle truncate
+            result_intervals.append( ["empty", interval[1], interval_to_remove[1]] )
+            interval[1] = interval_to_remove[2]
+
+    return result_intervals + [interval]
+
+
+class Dol:
+    HEADER_LEN = 0x100
+    __path = None
+    __header = None
+    __data = None
+    # List of 18 tuples [(offset, address, length, is_used), ] that describe all sections of the dol
+    __sections_info = None
+    # (address, length)
+    __bss_info = None
+    __entry_point = None
+    def __init__(self, path:Path):
+        self.__path = path
+        data = path.read_bytes()
+        self.__header = data[:Dol.HEADER_LEN]
+        self.__data = data[Dol.HEADER_LEN:]
+
+        self.__bss_info = ( int.from_bytes(data[0xd8:0xdc], "big"), int.from_bytes(data[0xdc:0xe0], "big") )
+        self.__entry_point = int.from_bytes(data[0xe0:0xe4], "big")
+
+        self.__sections_info = []
+        for i in range(18):
+            offset = int.from_bytes(data[i*4:i*4+4], "big")
+            address = int.from_bytes(data[0x48+i*4:0x48+i*4+4], "big")
+            length = int.from_bytes(data[0x90+i*4:0x90+i*4+4], "big")
+            is_used = (offset != 0) and (address != 0) and (length != 0)
+            self.__sections_info.append( (offset, address, length, is_used) )
+    # print a table with each sections
+    def __str__(self):
+        res = f"Entry point: {self.__entry_point:08x}\n\n"
+        res += "Section | Offset   | Address  | Length   | Used\n" + "-"*48 + "\n"
+        i = 0
+        for section in self.__sections_info:
+            res+= "text"+str(i) if i < 7 else "data"+str(i)
+            if i < 10: res += " "
+            res += f"  | {section[0]:08x} | {section[1]:08x} | {section[2]:08x} | {str(section[3])}\n"
+            i += 1
+        res += f"\nbss: address:{self.__bss_info[0]:08x} length:{self.__bss_info[1]:08x}"
+        return res
+    """
+    # search_raw: bytecode
+    # we could also identify text segments to improve search
+    def search_raw(self, bytecode:bytes):
+        if len(bytecode) == 0:
+            raise Exception("Error - No bytecode.")
+        offsets = []
+        for i in range(len(self.__data) - len(bytecode) + 1):
+            if self.__data[i:i+len(bytecode)] == bytecode:
+                offsets.append(self.resolve_img2virtual(i + Dol.HEADER_LEN))
+        return offsets if len(offsets) > 0 else None
+    """
+    # Resolve a dol absolute offset to a virtual memory address
+    def resolve_img2virtual(self, offset:int):
+        memory_address = None
+        for section_info in self.__sections_info:
+            if section_info[0] == 0: continue
+            if offset >= section_info[0] and offset < section_info[0] + section_info[2]:
+                return section_info[1] + offset - section_info[0]
+        raise InvalidImgOffsetError(f"Not found: {offset:08x}")
+    # Resolve a virtual memory address to a dol absolute offset
+    def resolve_virtual2img(self, address:int):
+        for section_info in self.__sections_info:
+            if section_info[0] == 0: continue
+            if address >= section_info[1] and address < section_info[1] + section_info[2]:
+                return section_info[0] + address - section_info[1]
+        raise InvalidVirtualAddressError(f"Not found in dol initial segments: {address:08x}")
+    def stats(self):
+        print(self)
+
+        # https://www.gc-forever.com/yagcd/chap4.html#sec4
+        # system:      0x80000000 -> 0x80003100
+        # available:   0x80003100 -> 0x81200000
+        # apploader:   0x81200000 -> 0x81300000
+        # Bootrom/IPL: 0x81300000 -> 0x81800000
+
+        # Now we have to generate a memory map with splited bss and empty spaces
+        # [ [section_name, beg_addr, end_addr, length], ... ]
+        result_intervals = [
+            ["system", 0x80000000, 0x80003100, 0x3100],
+            ["apploader", 0x81200000, 0x81300000, 0x100000],
+            ["Bootrom/IPL", 0x81300000, 0x81800000, 0x500000]]
+
+        i = 0
+        for section in self.__sections_info[:7]:
+            if section[3]:
+                result_intervals.append( [f".text{i}", section[1], section[1] + section[2], section[2]] )
+                i += 1
+
+        i = 0
+        for section in self.__sections_info[7:18]:
+            if section[3]:
+                result_intervals.append( [f".data{i}", section[1], section[1] + section[2], section[2]] )
+                i += 1
+
+        result_intervals.sort(key=lambda x: x[1])
+        i = 0
+        for bss_interval in remove_intervals_from_interval([None, self.__bss_info[0], self.__bss_info[0] + self.__bss_info[1]], result_intervals):
+            result_intervals.append( [f".bss{i}", bss_interval[1], bss_interval[2], bss_interval[2] - bss_interval[1]] )
+            i += 1
+
+        # We search now available program space
+        result_intervals.sort(key=lambda x: x[1])
+        empty_intervals = remove_intervals_from_interval(["empty", 0x80003100, 0x81200000], result_intervals)
+        for empty_interval in empty_intervals:
+            result_intervals += [[empty_interval[0], empty_interval[1], empty_interval[2], empty_interval[2] - empty_interval[1]]]
+
+        result_intervals.sort(key=lambda x: x[1])
+        str_buffer = "\nSection      | beg_addr | end_addr | length   |\n" + "-"*48 + "\n"
+        for interval in result_intervals:
+            str_buffer += f"{interval[0].ljust(12)} | {interval[1]:08x} | {interval[2]:08x} | {interval[3]:08x} | \n"
+
+        print(str_buffer)
+    def extract(self, filename:str, section_index:int):
+        if section_index > 17:
+            raise Exception("Error - Section index has to be in 0 - 17")
+
+        begin_offset = self.__sections_info[section_index][0] - self.HEADER_LEN
+        end_offset = begin_offset + self.__sections_info[section_index][2]
+
+        section_type = "text" if section_index < 7 else "data"
+        Path(f"{filename}_{section_type}{section_index}").write_bytes(self.__data[begin_offset:end_offset])
+    # [ [virtual_address:int, value:bytes], ... ]
+    def patch_action_replay(self, virtualaddress_bytes_list:list):
+        self.__data = bytearray(self.__data)
+        for virtualaddress_bytes in virtualaddress_bytes_list:
+            offset = self.resolve_virtual2img(virtualaddress_bytes[0])
+            print(f"Patching {virtualaddress_bytes[0]:08x} at dol offset {offset:08x} with value {virtualaddress_bytes[1].hex()}")
+            self.__data[offset: offset + len(virtualaddress_bytes[1])] = virtualaddress_bytes[1]
+
+
+# Parse an ini file and return a list of [ [virtual_address:int, value:bytes], ... ]
+# All ARCodes present in the ini will be enabled without taking care of [ActionReplay_Enabled] section
+# raise an Exception if lines are in invalid format:
+# * empty lines are removed
+# * lines beginning with $ are concidered as comments and are removed
+# * lines beginning with [ are concidered as comments and are removed
+# * others lines have to be in format: "0AXXXXXX XXXXXXXX" with (A=2 or A=4) and X in [0-9a-fA-F]
+def parse_action_replay_ini(path:Path):
+    action_replay_lines = path.read_text().splitlines()
+    pattern = re.compile("^(02|04)([0-9a-zA-Z]{6}) ([0-9a-zA-Z]{8})$")
+    result_list = []
+
+    for action_replay_line in action_replay_lines:
+        if len(action_replay_line) == 0:
+            continue
+        if action_replay_line[0] in ["$", "["]:
+            continue
+        res = pattern.fullmatch(action_replay_line)
+
+        if res is None:
+            raise InvalidIniFileEntryError(f"Error - Arcode has to be in format: '0AXXXXXX XXXXXXXX' with (A=2 or A=4) and X in [0-9a-fA-F] line \"{action_replay_line}\".")
+
+        virtual_address = int("80"+res[2], base=16)
+        bytes_value = None
+        if res[1] == "04":
+            bytes_value = int(res[3], 16).to_bytes(4, "big")
+        elif res[1] == "02":
+            bytes_value = (int(res[3][:4], 16) + 1) * int(res[3][4:], 16).to_bytes(2, "big")
+        else:
+            raise InvalidIniFileEntryError("Error - Arcode has to be in format: '0AXXXXXX XXXXXXXX' with (A=2 or A=4) and X in [0-9a-fA-F] line \"{action_replay_line}\".")
+        result_list.append( (virtual_address, bytes_value) )
+    return result_list
+
+
+def get_argparser():
+    import argparse
+    parser = argparse.ArgumentParser(description='dol file format utilities - [GameCube] v' + __version__)
+    parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
+    parser.add_argument('-v', '--verbose', action='store_true', help='verbose mode')
+    #parser.add_argument('-a', '--align', type=int, help='-a=10: alignment of files in the GCM ISO (default value is 4)', default=4)
+    parser.add_argument('input_path', metavar='INPUT', help='')
+    parser.add_argument('arg2', metavar='arg2', help='', default=None)
+
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument('-s', '--stats', action='store_true', help="-s boot.dol: Get stats about entry point, sections, bss and unused virtual address space.")
+    group.add_argument('-e', '--extract', action='store_true', help="-e boot.dol section_index: Extract a section. index must be between 0 and 17")
+    group.add_argument('-par', '--patch-action-replay', action='store_true', help="-p boot.dol action_replay.ini: Patch initialised data inside the dol with an ini file containing a list of [write] directives. Handle only ARCodes beginning with 04.")
+    return parser
+
+
+if __name__ == '__main__':
+    logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.INFO)
+    args = get_argparser().parse_args()
+
+    p_input = Path(args.input_path)
+
+    if args.verbose:
+        logging.getLogger().setLevel(logging.DEBUG)
+
+    if not p_input.is_file():
+        raise Exception("Error - Invalid dol file path.")
+
+    dol = Dol(p_input)
+
+    if args.stats:
+        dol.stats()
+    elif args.extract:
+        logging.info("### Extract section")
+        if args.arg2 is None:
+            raise Exception("Error - Section index has to be specified.")
+        index = int(args.arg2)
+
+        section_type = "text" if index < 7 else "data"
+        logging.info(f"Extracting section {index} in file {p_input.name}_{section_type}{index}...")
+        dol.extract(p_input.name, index)
+    elif args.patch_action_replay:
+        logging.info("### Patch dol using Action Replay ini file")
+        if args.arg2 is None:
+            raise Exception("Error - Action Replay ini file has to be specified.")
+        action_replay_ini_path = Path(args.arg2)
+        if not action_replay_ini_path.is_file():
+            raise Exception("Error - Invalid action replay ini file path.")
+
+        logging.info(f"Patching dol {p_input} using .ini file {action_replay_ini_path}...")
+        dol.patch_action_replay(parse_action_replay_ini(action_replay_ini_path))