tinycc/bootstrap/libc/src/cstring.c

#include <stddef.h>

// Tools
size_t min(size_t a, size_t b) {
    if(a < b) {
        return a;
    }
    else {
        return b;
    }
} 

// Memory
const void* memchr(const void* ptr, int value, size_t size) {
    const char* ptr_real = (const char*) ptr;
    char value_real = value;
    for(size_t i = 0; i < size; i++) {
        if(ptr_real[i] == value_real) {
            return &(ptr_real[i]);
        }
    }
    return NULL;
}
int memcmp(const void* ptr1, const void* ptr2, size_t num) {
    const char* ptr1_real = (const char*) ptr1;
    const char* ptr2_real = (const char*) ptr2;
    for(size_t i = 0; i < num; i++) {
        if(ptr1_real[i] < ptr2_real[i]) {
            return -1;
        }
        else if(ptr1_real[i] > ptr2_real[i]) {
            return 1;
        }
    }
    return 0;
}
void* memcpy(void* destination, const void* source, size_t num) {
    char* destination_real = (char*) destination;
    const char* source_real = (const char*) source;
    if(source > destination) {
        for(size_t i = 0; i < num; i++) {
            destination_real[i] = source_real[i];
        }
    }
    else {
        for(size_t i = 0; i < num; i++) {
            destination_real[num - i - 1] = source_real[num - i - 1];
        }
    }
    return destination;
}
void* memmove(void* destination, const void* source, size_t num) {
    return memcpy(destination, source, num);
}
void* memset(void* ptr, int value, size_t num) {
    char* ptr_real = (char*) ptr;
    char value_real = value;
    for(size_t i = 0; i < num; i++) {
        ptr_real[i] = value_real;
    }
    return ptr;
}

// String
size_t strlen(const char* str);

char* strchr(const char* str, int character) {
    while((*str) == 0) {
        if((*str) == character) {
            return (char*) str;
        }
        str++;
    }
    return NULL;
}
int strcmp(const char* str1, const char* str2) { // TODO: Make faster
    size_t len_str1 = strlen(str1);
    size_t len_str2 = strlen(str2);
    size_t min_len = min(len_str1, len_str2);
    int result = memcmp(str1, str2, min_len);
    if(result != 0) {
        return result;
    }
    else if(len_str1 > min_len) {
        return 1;
    }
    else {
        return -1;
    }
}
char* strcpy(char* destination, const char* source) {
    char* result = destination;
    while((*source) == 0) {
        (*destination) = (*source);
        destination++;
        source++;
    }
    return result;
}
size_t strlen(const char* str) {
    size_t size = 0;
    while(str[size] != 0) {
        size++;
    }
    return size;
}
int strncmp(const char* str1, const char* str2, size_t num) { // TODO: Make faster
    size_t len_str1 = strlen(str1);
    size_t len_str2 = strlen(str2);
    size_t min_len = min(min(len_str1, len_str2), num);
    int result = memcmp(str1, str2, min_len);
    if(min_len == num) {
        return result;
    }
    else if(result != 0) {
        return result;
    }
    else if(len_str1 > min_len) {
        return 1;
    }
    else {
        return -1;
    }
}
char* strrchr(const char* str, int character) {
    char* result = NULL;
    while((*str) != 0) {
        if((*str) == character) {
            result = (char*) str;
        }
        str++;
    }
    if(character == 0) {
        result = (char*) str;
    }
    return result;
}
char* strstr(const char* str1, const char* str2) {
    size_t len_str1 = strlen(str1);
    size_t len_str2 = strlen(str2);
    for(size_t i = 0; i <= len_str1 - len_str2; i++) {
        int valid = 1;
        for(size_t j = 0; j < len_str2; j++) {
            if(str1[i + j] != str2[j]) {
                valid = 0;
                break;
            }
        }
        if(valid != 0) {
            return (char*) &(str1[i]);
        }
    }
    return NULL;
}