script.py

# COPYRIGHT Théo BASTY - 2022

import sys
import time

import pikepdf
import re
from glob import glob

INST_PATTERN = re.compile("^\w+")
COMMENT_PATTERN = re.compile("#.*")

operations = {}
pdf_cache = {}
history = ["#PDFAutomate v1.1 - Beginning of history"]


def inst_open(instruction_line):
    global staging
    filename = re.match("OPEN (.*)", instruction_line).group(1)
    print("Opening " + filename)
    staging = pikepdf.open(filename, allow_overwriting_input=True)
operations["OPEN"] = inst_open


def inst_merge(instruction_line):
    global staging
    filenames = re.match("^MERGE (.*)$", instruction_line).group(1).split(" ")
    print("Merging files:", end='')
    for pattern in filenames:
        for file in glob(pattern):
            src = pikepdf.open(file)
            print(" " + file, end='')
            staging.pages.extend(src.pages)
    print(" - Done!")
operations["MERGE"] = inst_merge


def inst_swap(instruction_line):
    global staging
    pages = re.match("SWAP (\d+) (\d+)", instruction_line)
    p1, p2 = staging.pages[int(pages.group(1)) - 1], staging.pages[int(pages.group(2)) - 1]
    print("Swapping pages " + pages.group(1) + " and " + pages.group(2))
    staging.pages.append(p1)
    p1.emplace(p2)
    p2.emplace(staging.pages[-1])
    del staging.pages[-1]
operations["SWAP"] = inst_swap


def inst_remove(instruction_line):
    global staging
    pages = re.match("REMOVE ([0-9 ]+)", instruction_line).group(1).split(" ")
    pages = list(map(int, pages))
    pages.sort(reverse=True)
    print("Removing pages:", end='')
    for page in pages:
        print(" " + str(page), end='')
        del staging.pages[int(page) - 1]
    print(" - Done!")
operations["REMOVE"] = inst_remove


def inst_write(instruction_line):
    global staging
    filename = re.match("WRITE (.*)", instruction_line).group(1)
    print("Saving buffer as '" + filename + "'")
    staging.save(filename)
operations["WRITE"] = inst_write


def inst_keep(instruction_line):
    global staging
    pages = re.match("KEEP ([0-9 ]+)", instruction_line).group(1).split(" ")
    pages = list(map(int, pages))
    pages.sort(reverse=False)
    dst = pikepdf.new()
    print("Keeping some page in buffer:", end='')
    for page in pages:
        print(" " + str(page), end='')
        dst.pages.append(staging.pages[page - 1])
    staging.close()
    staging = dst
    print(" - Done!")
operations["KEEP"] = inst_keep


def inst_cache(instruction_line):
    global staging
    cache_name = re.match("CACHE (.*)", instruction_line).group(1)
    print("Placing buffer in cache entry '" + cache_name + "'")
    pdf_cache[cache_name] = staging
operations["CACHE"] = inst_cache


def inst_load(instruction_line):
    global staging
    cache_name = re.match("LOAD (.*)", instruction_line).group(1)
    print("Loading cache entry '" + cache_name + "' in buffer")
    staging = pdf_cache[cache_name]
operations["LOAD"] = inst_load


def inst_quit(instruction_line):
    global staging
    print("Good Bye !")
    sys.exit()
operations["QUIT"] = inst_quit


def inst_reset(instruction_line):
    global staging
    print("Resetting the buffer")
    staging = pikepdf.new()
operations["RESET"] = inst_reset


def inst_history(instruction_line):
    global history
    for line_num, instruction in enumerate(history, start=1):
        line_num = len(history) - line_num
        print("{:3d}: {:s}".format(line_num, instruction))
operations["HISTORY"] = inst_history


def inst_savehist(instruction_line):
    global history
    filename = re.match("SAVEHIST (.*)", instruction_line).group(1)
    print("Saving history as '" + filename + "'")
    instfile = open(filename, mode="w")
    for histline in history:
        instruct = INST_PATTERN.match(histline)
        if instruct is None or (instruct.group(0) != "HISTORY" and instruct.group(0) != "SAVEHIST"):
            instfile.write(histline + "\n")
    instfile.close()
operations["SAVEHIST"] = inst_savehist


if __name__ == '__main__':
    if len(sys.argv) >= 2:
        from_stdin = False
        instructions = open(sys.argv[1])
        startingAt = time.time()
    else:
        from_stdin = True
        instructions = sys.stdin

    staging = pikepdf.new()
    if from_stdin:
        print(">", end="")
    for i, line in enumerate(instructions, start=1):
        line = COMMENT_PATTERN.sub("", line).strip()
        if not line:
            print("")
            continue
        regexLine = INST_PATTERN.match(line)
        if regexLine is None:
            print("No instructions found on line " + str(i), file=sys.stderr)
            if not from_stdin:
                break
        inst = regexLine.group(0)
    
        if inst in operations.keys():
            if len(history) > 100:
                history.pop(0)
            history.append(line)
            operations[inst](line)
        else:
            print("Instruction " + str(inst) + " on line " + str(i) + " is not a valid instruction", file=sys.stderr)
            if not from_stdin:
                break

        if from_stdin:
            print(">", end="")

    if not from_stdin:
        print("==========================================")
        print("Instructions ran in " + str(round((time.time() - startingAt) * 1000)) + "ms")