classparse

C based Java classfile parser. Simple and easy.

Getting Started

Using classparse is easy, refer to the building section on guide how to install. Basic usage is covered in the examples section.

Installation and Building

To build and install the library globally:

make TARGET=linux       # Build for Linux
sudo make install       # Install header and shared library

Build Targets

Command	Description
make or make dev	Development build (sanitizers, debug symbols, profiling)
make prod	Production build (optimized with -O3 and LTO)

Platform Selection

Append TARGET=<platform> to any build command:

Target	Description	Output Extension
TARGET=linux	Linux shared library	.so
TARGET=win32	Windows DLL	.dll
TARGET=wasm	WebAssembly module	.wasm

Examples:

make dev TARGET=wasm    # Dev build for WebAssembly
make prod TARGET=win32  # Optimized Windows build

Standalone mode

Enable by defining the STANDALONE macro or setting STANDALONE=1 in Makefile

Classparse supports standalone mode, which will use minimal amount of functions from the standard C library. This is optimal for things like custom operating systems or any non-libc compliant systems. Heres a list of extern'd functions, which needs to be present:

1. void *malloc(size_t size), void free(void *ptr) - required for memory allocations
2. int strcmp(const char *s1, const char *s2)
3. char *strcpy(char *dest, const char *src)
4. char *strchr(const char *s, int c), char *strrchr(const char *s, int c)
5. size_t strlen(const char *ptr)
6. void *memcpy(void *dest, const void *src)

We tried to strip it down as much as possible, but some of these are just necessity :)

Build Configuration

Development Mode (make dev)

• Compiler: -std=gnu11
• Flags: -g -Wall -Wextra -fsanitize=address -fno-omit-frame-pointer -pg
• No optimizations

Production Mode (make prod)

• Compiler: -std=gnu11
• Flags: -O3 -flto -Wall -Wextra
• Full optimizations enabled

Examples

Examples can be found inside the examples/ directory, you can compile all of them using the make command. Please note that it's recommended to run make and make install in the root directory to assure that the linkage of the library will succceed! These are some of the most commonly used functions:

1. ClassFile *ReadFromStream(FILE *stream); will read the given classfile from C-style stream.
2. void FreeClassFile(ClassFile *cf); should be always used to free the resources allocated by reading.
3. Method *GetMethodByName(ClassFile *cf, const char *name); etc. can be used as utilities to make your life easier.

The rest of them can be found in the classparse.h

Contributing

The library is pretty easy to understand, so if you have any recommendations, feel free to submit your changes as PR, I will gladly merge them!

License

Licensed under the MIT License.