C实现本地资源文件编译时加载

2024-10-17

本文作者原创，首发在本博客；CSDN 上的同名文章已标注为转载并回链到本页：https://blog.csdn.net/qq_30220519/article/details/143028617

目标

本地资源文件编译时加载工具，旨在帮助开发者简化资源管理流程，提高编译效率，确保资源文件在运行时能够快速、可靠地加载。

下载

实现代码

#include <cstdio>
#include <cstring>
#include <string>
#include <unordered_set>
#include <fstream>
#include <memory>
#include <cassert>

const char *inputFileName = nullptr, *outputFileName = nullptr;
const char *varName = nullptr, *prefixes = nullptr;
std::unordered_set<std::string> includeFilePaths;
size_t chunkSize = 4096;

static const char *_requireArg(int argc, char* argv[], int &i) {
    i += 1;
    if(i >= argc)
        return nullptr;
    return argv[i];
}

#define _printError(msg, ...) fprintf(stderr, "Error: " msg "\n", ##__VA_ARGS__)
#define _printWarning(msg, ...) fprintf(stderr, "Warning: " msg "\n", ##__VA_ARGS__)

char digit2Hex(uint8_t digit) {
    assert(digit < 16);

    return digit < 10 ? digit + '0' : (digit - 10) + 'a';
}

int main(int argc, char *argv[]) {
    for(int i = 1 ; i < argc; ++i) {
        const char *curArg = argv[i];

        if(!strcmp(curArg, "-I")) {
            const char *path = _requireArg(argc, argv, i);
            if(!path) {
                _printError("-I requires an include path");
                return -1;
            }

            includeFilePaths.insert(path);
        } else if(!strcmp(curArg, "-o")) {
            const char *path = _requireArg(argc, argv, i);
            if(!path) {
                _printError("-o requires an output path");
                return -1;
            }

            if(outputFileName) {
                _printError("Output file name is already set");
                return -1;
            }

            outputFileName = path;
        } else if(!strcmp(curArg, "-n")) {
            const char *name = _requireArg(argc, argv, i);
            if(!name) {
                _printError("-n requires a variable name");
                return -1;
            }

            if(varName) {
                _printError("Variable name is already set");
                return -1;
            }

            varName = name;
        } else if(!strcmp(curArg, "-s")) {
            const char *chunkSizeStr = _requireArg(argc, argv, i);
            if(!chunkSizeStr) {
                _printError("-s requires a chunk size");
                return -1;
            }

            unsigned long long chunkSizeIn = strtoull(chunkSizeStr, nullptr, 10);
            if(chunkSizeIn > SIZE_MAX) {
                _printError("Chunk size is bigger than the size supported by the machine");
                return -1;
            }

            chunkSize = chunkSizeIn;
		} else if (!strcmp(curArg, "-p")) {
			const char *prefixesStr = _requireArg(argc, argv, i);
			if (!prefixesStr) {
				_printError("-p requires a prefixes string");
				return -1;
			}

			if (prefixes) {
				_printError("Prefixes string is already specified");
				return -1;
			}

			prefixes = prefixesStr;
		} else {
            if(inputFileName) {
                _printError("Input file name is already set");
                return -1;
            }

            inputFileName = curArg;
        }
    }

    if(!inputFileName) {
        _printError("Missing input file name");
        return -1;
    }
    
    if(!outputFileName) {
        _printError("Missing output file name");
        return -1;
    }
    
    if(!varName) {
        _printError("Missing variable name");
        return -1;
    }

    std::ifstream is(inputFileName, std::ios::in | std::ios::binary);
    if(is.bad() || is.fail()) {
        _printError("Error opening the input file");
        return -1;
    }

    std::ofstream os(outputFileName, std::ios::out | std::ios::trunc);
    if(os.bad() || os.fail()) {
        _printError("Error opening the output file");
        return -1;
    }

    for(auto i : includeFilePaths) {
        os << "#include " << i << std::endl;
    }

	if (prefixes)
		os << prefixes << " ";

    os << "const char " << varName << "[] = ";

	size_t totalFileSize;
	{
		is.seekg(0, std::ios::end);
		std::streampos streamOff = is.tellg();
		is.seekg(0, std::ios::beg);

		if (streamOff < 0) {
			_printError("Error evaluating the file size");
			return -1;
		}

		totalFileSize = (size_t)streamOff;
	}

    size_t totalSizeWritten = 0;
    {
        std::unique_ptr<char[]> chunk = std::make_unique<char[]>(chunkSize);

        char byteBuf[] = "\\x00";
		char newline = '"';
		char jumpLine = '\n';
        while (totalSizeWritten < totalFileSize) {
			std::streamsize szRead;

			is.read(chunk.get(), chunkSize);
			szRead = is.gcount();
            totalSizeWritten += szRead;

			if (!is.eof()) {
				if (is.fail() || is.bad()) {
					_printError("Error reading the input file");
					return -1;
				}
			}

			os.write(&jumpLine, 1);
			os.write(&newline, 1);
            for(size_t i = 0 ; i < (size_t)szRead; ++i) {
                uint8_t curByte = *(uint8_t*)(chunk.get() + i);
                
                byteBuf[2] = digit2Hex(curByte >> 4);
                byteBuf[3] = digit2Hex(curByte & 0b1111);

                os.write(byteBuf, sizeof(byteBuf) - 1);
            }
			os.write(&newline, 1);

            
            if(os.fail() || os.bad()) {
                _printError("Error writing the output file");
                return -1;
            }
        }
    }

    os << ";" << std::endl;

	if (prefixes)
		os << prefixes << " ";

    os << "const size_t " << varName << "_length = " << totalSizeWritten << ";" << std::endl;

    is.close();
    os.close();

    return 0;
}

用法

file2c.exe -o output.c -n thbrk thbrk.tri

反转文件

const char thbrk[] = "\xd9\xfc\xd9\xfc\x00\x00\x00\x01\x00\x00\x0e\x01\x00\x00\x0e\x5b\xda\xfc\xda\xfc\x00\x00\x91\x31\xff\xff\x6e\xd2\xff\xff\x6f\xef\x00\x00\x8e\x79\x00\x00\x00\x00\xff\xff\xff\xff\x00...";
const size_t thbrk_length = 587736;

#include <fstream>
int main() {
	std::fstream output("output.bin", std::ios::app | std::ios::out | std::ios::binary);
	if(!output.is_open())
		return 0;
	uint8_t curByte = 0;
	for(int i = 0; i < thbrk_length; ++i) {
		curByte = thbrk[i];
		output.write((char *)&thbrk[i], 1);
	}
	output.flush();
	output.close();
}

参考

GitHub - pyxherb/file2c: Convert and embed files into C sources.

目标

下载

实现代码

用法

反转文件

参考

创作不易，小小的支持一下吧！