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#pragma once
#include <type_traits.h>
#include <types.h>
/**
* Calculate the length of the string (in bytes) pointed to by str, excluding
* the terminating null character.
*/
constexpr size_t strlen(const char* str) {
size_t len = 0;
while (str[len])
++len;
return len;
}
/* reverse: reverse string s in place */
constexpr void reverse(char s[], int strlen) {
int i, j;
char c;
for (i = 0, j = strlen - 1; i < j; i++, j--) {
c = s[i];
s[i] = s[j];
s[j] = c;
}
}
/* itoa: convert n to characters in s */
template <typename T, int base = 10>
constexpr size_t itoa(T n, char s[]) {
const bool is_negative = (n < 0);
if constexpr (!is_unsigned<T>()) {
if (n < 0)
n = -n;
}
int i = 0;
do { /* generate digits in reverse order */
s[i++] = "0123456789abcdef"[n % base]; /* get next digit */
} while ((n /= base) > 0); /* delete it */
if (is_negative)
s[i++] = '-';
s[i] = '\0';
reverse(s, i);
return i;
}
class ViewIterator {
public:
virtual char next() = 0;
virtual operator bool() const = 0;
};
class StringView {
public:
class Iterator : public ViewIterator {
friend class StringView;
public:
char next() override { return p->buffer[pos++]; }
operator bool() const override { return (pos < p->m_length); }
private:
Iterator(const StringView* s) : p(s) {}
size_t pos = 0;
const StringView* p;
};
friend class Iterator;
StringView(const char* d) : buffer{d}, m_length{strlen(d)} {}
StringView(const char* d, size_t l) : buffer{d}, m_length{l} {}
Iterator begin() const { return Iterator(this); }
private:
const char* const buffer;
const size_t m_length;
};
class IntegerView {
public:
template <typename T>
struct HexFormat {
T n;
};
class Iterator : public ViewIterator {
friend class IntegerView;
public:
char next() override { return _p->buffer[pos++]; };
operator bool() const override { return (pos < _p->length); }
private:
Iterator(const IntegerView* v) : _p(v) {}
size_t pos = 0;
const IntegerView* _p;
};
IntegerView(int32_t n) { length = itoa(n, buffer); }
template <typename T>
IntegerView(HexFormat<T> f) {
buffer[0] = '0';
buffer[1] = 'x';
length = itoa<T, 16>(f.n, buffer + 2) + 2;
}
Iterator begin() const { return Iterator(this); }
private:
char buffer[128];
size_t length = 0;
};
using hex = IntegerView::HexFormat<int32_t>;
using uhex = IntegerView::HexFormat<uint32_t>;
using hex_addr = IntegerView::HexFormat<uint64_t>; // TODO causes crash
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