Xelix memory inspector

xelix-meminsp.c

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

#define BUFFERSIZE 256
// Should be a multiple of 4
#define COLUMN 4 * 3

#define is_digit(C) ((C) >= '0' && (C) <= '9')

uint64_t atoi(const char* s) {
	uint64_t n = 0;
	while(*s != 0)
	{
		if(!is_digit(*s))
			return -1;
		
		n = 10 * n + *s++ - '0';
	}

	return n;
}

int main()
{
	printf( \
		"Memory inspector for Xelix.\n" \
		"Please enter a pointer (In decimal format) or 'quit' to quit.\n" \
		);

	char* buffer = malloc(BUFFERSIZE);

	while(true)
	{
		printf("meminsp> ");
		memset(buffer, 0, 256);
		fgets(buffer, 256, stdin);

		if(buffer[0] == '\n')
			continue;

		// Cut off the \n
		buffer[strlen(buffer) - 1] = 0;

		if(!strcmp(buffer, "quit"))
			break;
	
		uint64_t pointer = atoi(buffer);
		if(pointer == -1)
		{
			printf("Sorry, but that doesn't look like a valid pointer (Hexadecimal doesn't work!).\n");
			continue;
		}

		printf("Showing memory at 0x%x (%d)\n", pointer, pointer);

		for(int i = 0; i < 23; i++)
		{
			printf("0x%x\t", pointer + i * COLUMN);
			for(int j = 0; j < COLUMN; j += 4)
			{
				uint32_t c = *((uint32_t*)pointer + i * COLUMN + j);
				//printf("%d\t", (uint32_t*)pointer + i * COLUMN + j);

				int padding = 10 - intlen(c);
				if(padding < 0) padding = 0;
				//printf("p: %d\n", padding);

				for(int k = 0; k < padding; k++)
					printf("0");
				
				printf("%d", c);
				printf(" ");
			}

			printf("\t");

			for(int j = 0; j < COLUMN; j++)
			{
				char c = *((char*)pointer + i * COLUMN + j);
				// All printable ascii chars are between ' ' (32) and '~' (126).
				if(c >= ' ' && c <= '~')
					// Show printable chars in white (versus gray for normal text)
					printf("\e[0;37m%c\e[0m", c);
				else
					printf(".");
			}

			printf("\n");
		}
	}
}%