Simple conversion lib

conv.c

#include "conv.h"
#include <string.h>

uint64_t toUint64T(const char * nstr) {
    uint8_t digit;
    uint64_t res = 0;

    for (size_t i = 0; i < strlen(nstr); ++i) {
        digit = nstr[i] - '0';
        res = res * 10 + digit;
    }

    return res;
}

uint32_t toUint32T(const char * nstr) {
    return (uint32_t) toUint64T(nstr);
}

size_t toSizeT(const char * nstr) {
    return (size_t) toUint64T(nstr);
}

int64_t toInt64T(const char * nstr) {
    int64_t res = 0;
    uint8_t digit, sign = 1;

    if (nstr[0] == '-') {
        sign = -1;
        nstr++;
    }

    for (size_t i = 0; i < strlen(nstr); ++i) {
        digit = nstr[i] - '0';
        res = res * 10 + digit;
    }

    return res * sign;
}

int32_t toInt32T(const char * nstr) {
    return (int32_t) toInt64T(nstr);
}

conv.h

#ifndef CONV_H
#define CONV_H

#include <stdint.h>
#include <stddef.h>

size_t toSizeT(const char *);
uint32_t toUint32T(const char *);
uint64_t toUint64T(const char *);

int32_t toInt32T(const char *);
int64_t toInt64T(const char *);

#endif