neatcpp 1.2.0

A minimalistic C preprocessor preserving the original C code formatting

Introduction

Neatcpp is a minimalistic C code preprocessor written in Python. The preprocessor is not intended to create source files for the compiler. It is aimed at the creation of C source files with correctly expanded macros for the purposes of static analysis or code coverage analysis.

The neatcpp produces a code with formatting very close to the original code, i.e., the line endings, intendantion and comments are preserved, even in the expanded macro bodies. It is also possible to keep the original preprocessor directives.

Usage

Neatcpp as a Python module

Neatcpp preprocessor object should be created as an instance of the NeatCpp class and controlled through its public object attributes and methods.

The code below shows the basic usage of neatcpp as a Python module. See the samples\module_usage directory for the executable example listed below together with another slightly more advanced sample script.

# Import preprocessor class NeatCpp
from neatcpp import NeatCpp


SAMPLE_CODE = """
#define CUBE(X)     (X) * (X) * (X)
#define A           5
#define B           3

a = CUBE(A);
"""

# Create the preprocessor object.
neatcpp = NeatCpp()

# Process C code defined in a SAMPLE_CODE string.
neatcpp.process_code(SAMPLE_CODE)

# Print full global output. The full output means that everything from the original code
# (including preprocessor directives) is included in the output.
print(neatcpp.output_full)
# Prints:
# #define CUBE(X)     (X) * (X) * (X)
# #define A           5
# #define B           3
#
# a = (5) * (5) * (5);

# Print standard preprocessed output without the processed directives and comments
# not related to the remaining code.
print(neatcpp.output)
# Prints:
# a = (5) * (5) * (5);

print(neatcpp.expand_macros("b = CUBE(B + 1);"))
# Prints:
# b = (3 + 1) * (3 + 1) * (3 + 1);

print(neatcpp.evaluate("CUBE(2 + 2)"))
# Prints:
# 64

print(neatcpp.is_true("CUBE(A - B) < CUBE(A + B)"))
# Prints:
# True

# Reset internal preprocessor output.
neatcpp.reset_output()

# Add include directory to search for included files.
neatcpp.add_include_dirs("path/to/incl/dir")

# Process C code defined in file.
neatcpp.process_files("path/to/src.c")

# Save preprocessor output to the output file.
neatcpp.save_output_to_file("path/to/src_processed.c")

Neatcpp as a standalone script

C source files can be processed from a commmand line with the arguments in a following format:

python neatcpp.py in1.c [in2.c ...] out.c [-s sin1.c [sin2.c ...]] [-i incl1 [incl2 ...]] [-x excl1 [excl2 ...]] [-f] [-v 0-2] [-V] [-h]

Positional arguments:

• in1.c [in2.c ...] - Input source files to be processed.
• out.c - Output source file with processed code from all specified input files.

Optional arguments:

• -s sin1.c [sin2.c ...] - Input source files processed silently , i.e., without generated output, before processing the main input files.
• -i incl1 [incl2 ...] - Included directories to search for the input files or for the included files defined by the #include statements in the input sources.
• -x - Excluded macros or files. #define and #include statements for these identifiers will not be processed.
• -f - Option to enable full output, i.e., to include directives, all comments and whitespaces in the preprocessor output
• -v 0-2 - Set console log verbosity level (0 = logging OFF with errors still shown).
• -V - Show program name and version.
• -h - Show help message and exit.

See the example in the samples\script_usage directory illustrating the command line usage.