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# There is no shebang because this is not to be run as a program.
#
# Electronic memo protocol utility functions.
#
# Written by Andrew Yu <https://www.andrewyu.org/>.
#
# This work is in the public domain. See the NOCOPYRIGHT file for
# details.
#
import ememo_errors
import re
re_named_address = re.compile(b"(.*) <(.*)\\@(.*)>")
re_unnamed_address = re.compile(b"^[<](.*)\\@(.*)[>]$")
def parse_address(s): # Returns name, user, host.
attempt_named_address = re_named_address.match(s)
if attempt_named_address:
return (
attempt_named_address.group(1),
attempt_named_address.group(2),
attempt_named_address.group(3),
)
attempt_unnamed_address = re_unnamed_address.match(s)
if attempt_unnamed_address:
return (
None,
attempt_unnamed_address.group(1),
attempt_unnamed_address.group(2),
)
return None # No results, invalid address.
def parse_header_line(line):
if b": " not in line:
raise ememo_errors.E_HEADER_FORMAT
return line.split(b": ", 1)
def assemble_headers(headers, use_carriage_returns_too=False):
buffer = b""
for k, v in headers.items():
buffer += k + b": " + v + b"\n"
buffer += b"\n"
return buffer
def parse_header_and_leave_rest(mail_buffer):
header_lines = []
buffer = b""
last_char = 0
last_char = b""
i = 0
while i < len(mail_buffer):
char = mail_buffer[i].to_bytes(1, "big")
if char == b"\n" and last_char != b"\n":
header_lines.append(buffer)
buffer = b""
elif char == b"\n" and last_char == b"\n":
buffer = b""
i += 1
break
elif char != b"\r":
buffer += char
last_char = char
i += 1
buffer = mail_buffer[i:]
headers = {}
for header_line in header_lines:
key, value = parse_header_line(header_line)
headers[key] = value
return headers, buffer
def extract_attachments(buffer):
attachments = {}
current_size_specifier_buffer = b""
current_filename_buffer = b""
current_data_buffer = b""
reading_mode = 0 # 0size, 1filename, 2data
i = 0
while i < len(buffer):
char = buffer[i].to_bytes(1, "big")
if reading_mode == 0 and char not in [b" ", b"\n"]:
current_size_specifier_buffer += char
elif reading_mode == 1 and char != b"\n":
current_filename_buffer += char
elif reading_mode == 0 and char == b" ":
reading_mode = 1
elif reading_mode == 0 and char == b"\n" and not current_size_specifier_buffer:
pass
elif reading_mode == 0 and char == b"\n" and current_size_specifier_buffer:
if b"" in attachments.keys():
raise ememo_errors.E_MULTIPLE_UNNAMED_ATTACHMENTS
if current_size_specifier_buffer[-1] == b"\r":
current_size_specifier_buffer = current_size_specifier_buffer[0:-1]
try:
current_size_specifier = int(current_size_specifier_buffer)
except ValueError:
raise ememo_errors.E_SIZE_NOT_NUMBER
reading_mode = 2
current_data_buffer += buffer[i + 1 : i + 1 + current_size_specifier]
i += current_size_specifier
attachments[b""] = current_data_buffer
current_filename_buffer = b""
current_data_buffer = b""
current_size_specifier_buffer = b""
reading_mode = 0
elif reading_mode == 1 and char == b"\n":
if current_filename_buffer[-1] == b"\r":
current_filename_buffer = current_filename_buffer[0:-1]
try:
current_size_specifier = int(current_size_specifier_buffer)
except ValueError:
raise ememo_errors.E_SIZE_NOT_NUMBER
reading_mode = 2
print(buffer, i + 1, i + 1 + current_size_specifier)
current_data_buffer += buffer[i + 1 : i + 1 + current_size_specifier]
i += current_size_specifier
attachments[current_filename_buffer] = current_data_buffer
current_filename_buffer = b""
current_data_buffer = b""
current_size_specifier_buffer = b""
reading_mode = 0
else:
raise ememo_errors.ServerFatal(
"reading mode shouldn't be 2 when char-scanning"
)
i += 1
return headers, attachments
|
