lab0.1_letscontinue/str.c

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "str.h"
#include "util.h"

#define INIT_SZ 20

//Внутренняя функция,
//позволяет убедиться что строка может вместить как минимум newsz символов
void
_str_ensure(str *s, int newsz)
{
	int tmp;
	newsz += 1; // добавляем единичку чтобы влез нулевой байт
	if (newsz < s->capacity)
		return;

	tmp = s->capacity * 2;
	if (tmp > newsz) {
		newsz = tmp;
	}
	s->ptr = xrealloc(s->ptr, newsz);
	s->capacity = newsz;
}

void
str_init(str *s)
{
	assert(s);
	s->len = 0;
	s->capacity = INIT_SZ;
	s->ptr = xmalloc(INIT_SZ);
	s->ptr[0] = '\0';
}

void
str_deinit(str *s)
{
	if (s->ptr)
		free(s->ptr);
	s->ptr = NULL;
	s->len = 0;
	s->capacity = 0;
}

void
str_init_data(str *s, const char *initial)
{
	assert(s && initial);
	int len = strlen(initial);
	s->len = len;
	s->capacity = len + 1;
	s->ptr = xmalloc(s->capacity);
	memcpy(s->ptr, initial, len + 1);
}

char *
str_data(str *s)
{
	assert(s);
	return s->ptr;
}

void
str_set(str *s, char *cstr)
{
	assert(s && cstr);
	int len = strlen(cstr);
	_str_ensure(s, len);
	memcpy(s->ptr, cstr, len + 1);
	s->len = len;
}

str
str_copy(str *s)
{
	assert(s);
	str new_str;
	str_init_data(&new_str, s->ptr);
	return new_str;
}

int
str_count(str *s, char ch)
{
	assert(s);
	int count = 0;
	for (int i = 0; i < s->len; i++) {
		if (s->ptr[i] == ch) {
			count++;
		}
	}
	return count;
}

void
str_append(str *s, char *cstr)
{
	assert(s && cstr);
	int len = strlen(cstr);
	str_append_n(s, cstr, len);
}

void
str_append_n(str *s, char *cstr, int len)
{
	assert(s && cstr);
	_str_ensure(s, s->len + len);
	memcpy(s->ptr + s->len, cstr, len);
	s->len += len;
	s->ptr[s->len] = '\0';
}

void
str_shrink(str *s, int len)
{
	assert(s && len >= 0);
	if (len < s->len) {
		s->len = len;
		s->ptr[s->len] = '\0';
	}
}

int
str_find(str *s, char *substr)
{
	assert(s && substr);
	char *p = strstr(s->ptr, substr);
	if (p == NULL)
		return -1;
	return p - s->ptr;
}

str
str_sub(str *s, int start_idx, int length)
{
	assert(s && start_idx >= 0 && length >= 0);

	str s2;
	str_init(&s2);
	if (start_idx >= s->len) {
		return s2; // пустая строка
	}
	
	int actual_length = length;
	if (start_idx + length > s->len) {
		actual_length = s->len - start_idx;
	}
	
	str_append_n(&s2, s->ptr + start_idx, actual_length);
	return s2;
}


// Hint: you can create temporary string object!
int str_replace(str *s, char *substr, char *replacement)
{
    assert(s && substr && replacement);
    int substr_len = strlen(substr);
    int count = 0;
    str temp;
    str_init(&temp); 
    
    int pos = 0;
    int found_pos;
    found_pos = str_find(s, substr);
    //poziciya iscomogo

    while (found_pos != -1) {
        str_append_n(&temp, s->ptr + pos, found_pos - pos);
	//dobavlyaet str mezhdu proshlym i sled vhozhdenyem
        str_append(&temp, replacement);
        //dobavlyaem zamenu

        pos = found_pos + substr_len;
        count++;
	//perehodim na pos posle zamenennoi str 
        
        str search_str;
        str_init(&search_str);
	//esche odna vremennaya stroka
        str_append_n(&search_str, s->ptr + pos, s->len - pos);
	//copiruem v neye vse posle pos
        found_pos = str_find(&search_str, substr);
	//ichem v nei novoe vhozhdeniye
        if (found_pos != -1) {
            found_pos += pos;
        }
	//nahodim poziciyu v ishodnoy str
        str_deinit(&search_str);
    }
    if (pos < s->len) {
        str_append_n(&temp, s->ptr + pos, s->len - pos);
    }
    //dobavlyaem ostatok str
    
    str_set(s, str_data(&temp));
    
    str_deinit(&temp);
    
    return count;
}