hex text string to hex file

principle

1. Remove invalid characters "0x", "\n", spaces, etc., starting from the first valid character (ie 0~F), and output a formatted HEX byte for every 2 valid characters that meet the conversion conditions.
2. After the character string is input, every two characters are converted into a byte (Hex), such as: 9F01 saves four bytes in ASCII code, and outputs two bytes in a hexadecimal file: 9F01

How to use

Set the absolute path (path + file name) of input/output, such as:

日志| please set source file path:
输入| D:/test/input.txt
日志| please set output file path:
输入| D:/test/output.txt

program

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Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define _CRT_SECURE_NO_WARNINGS
#define PAYLOAD_OFFSET 0
#define INVALID_CHARACTOR 0x10	//valid:0x0~0xF
unsigned char HexChar(unsigned char c);
char* getFilePath(void);
int find_next_number(unsigned char* pbData, int size);

int main(void)
{
    
    
	size_t result = -1;
	FILE* pFile = NULL;

	unsigned char* pbFileData = NULL;
	unsigned char* pbHexData = NULL;
	int dFileSize = 0;

	char* pbSourcePath = NULL;
	char* pbOutput = NULL;

	printf("please set source file path: \n");
	pbSourcePath = getFilePath();
	printf("please set output file path: \n");
	pbOutput = getFilePath();

	if (!pbSourcePath || !pbOutput) {
    
    
		printf("[error] invalid path of %s.\n", (!pbSourcePath ? "source file" : "ouput file"));
		return -1;
	}

	pFile = (FILE*)fopen(pbSourcePath, "rb");
	if (!pFile) {
    
    
		printf("[error] failed to open file: %s.\n", pbSourcePath);
		return -1;
	}
	fseek(pFile, 0L, SEEK_END);
	dFileSize = ftell(pFile);
	rewind(pFile);
	pbFileData = (unsigned char*)malloc(dFileSize);
	pbHexData = (unsigned char*)malloc(dFileSize / 2);
	if (!pbFileData || !pbHexData) {
    
    
		printf("[error] failed to alloc memory.\n");
		return -1;
	}
	memset(pbFileData, 0x00, dFileSize);
	memset(pbHexData, 0x00, dFileSize / 2);

	printf("source file size: %d.\n", dFileSize - PAYLOAD_OFFSET);
	result = fread(pbFileData, dFileSize, 1, pFile);
	if (1 != result)
	{
    
    
		fputs("reading error", stderr);
		printf("[error] failed to read file: %s\n", pbSourcePath);
		free(pbFileData);
		pbFileData = NULL;
		return -1;
	}
	int i = 0;
	int j = PAYLOAD_OFFSET;
	j += find_next_number(&pbFileData[j], dFileSize - j);
	for (; j + 1 < dFileSize; j += 2 + find_next_number(&pbFileData[j + 2], dFileSize - j - 2))
	{
    
    
		if (INVALID_CHARACTOR != HexChar(pbFileData[j + 1]))
			pbHexData[i++] = (HexChar(pbFileData[j]) << 4) + HexChar(pbFileData[j + 1]);
		else
			printf("[error] ignore a half-byte '%c%c', offset = %d\n", pbFileData[j], pbFileData[j + 1], j);
	}
	i--;
	fclose(pFile);

	FILE* fp = fopen(pbOutput, "wb");
	if (fp == NULL) {
    
    
		printf("[error] failed to open file: %s.\n", pbOutput);
		return -1;
	}
	fwrite(pbHexData, 1, i, fp);
	fclose(fp);

	printf("translation complete, file size: %d.\n", i);
	return 0;
}

int find_next_number(unsigned char* pbData, int size)
{
    
    
	int i = 0;
	for (; i < size && INVALID_CHARACTOR == HexChar(pbData[i]); i++)
		;
	return i;
}

char* getFilePath(void)
{
    
    
#define PATH_MAX_LEN 512
	char* p = NULL;
	int i = 0;
	p = (char*)malloc(PATH_MAX_LEN);
	if (!p)
		return NULL;
	for (i = 0; i < PATH_MAX_LEN; i++)
	{
    
    
		scanf("%c", &p[i]);
		if ('\n' == p[i])
			break;
	}
	if (i < PATH_MAX_LEN) {
    
    
		p[i] = 0;
	}
	else {
    
    
		printf("file path too long.\n");
		free(p);
		return NULL;
	}

	return p;
}

unsigned char HexChar(unsigned char c)
{
    
    
	if ((c >= '0') && (c <= '9'))
		return c - 0x30;
	else if ((c >= 'A') && (c <= 'F'))
		return c - 'A' + 10;
	else if ((c >= 'a') && (c <= 'f'))
		return c - 'a' + 10;
	return INVALID_CHARACTOR;
}