Strings

Makefile

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+CC = gcc
+CCFLAGS = -O3
+STRING_PATH = src/string
+
+all: $(STRING_PATH)/string.a
+	$(CC) $(CCFLAGS) src/main.c -o main $^
+
+.PHONY: string
+string: $(STRING_PATH)/string.a
+$(STRING_PATH)/string.a: $(STRING_PATH)/string.o
+	ar rcs $(STRING_PATH)/string.a $^
+$(STRING_PATH)/string.c: $(STRING_PATH)/string.h
+$(STRING_PATH)/string.o: $(STRING_PATH)/string.c $(STRING_PATH)/string.h
+	$(CC) $(CCFLAGS) -c $< -o $(STRING_PATH)/string.o

Readme.md

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+# Klib (Erik's C standard library)
+
+KLib is my own library to use with the C programming language
+Use are your own risk. Fully documented on the headers.

src/main.c

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+#include "string/string.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+int main()
+{
+    // Create the string.
+    String *string = string_create("Hello world");
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Add another text to the string.
+    string_add(string, ", this is a nice example of dynamic strings");
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Pop the last value of the string.
+    char pop = string_pop(string);
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Push a new value at the end of the string.
+    string_push(string, pop);
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Add anothe string toghether.
+    String *string2 = string_create(" yey!!!");
+    string_concat(string, string2);
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Get a substring
+    string_substring(string, 13, 34);
+    printf("[Length: %d, Capacity: %d]:\n%s\n\n", string->length, string->capacity, string->text);
+
+    // Delete the string memory.
+    string_delete(string);
+
+    return EXIT_SUCCESS;
+}

src/string/string.c

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+#include "string.h"
+#include <string.h>
+#include <stdlib.h>
+
+static void reallocate_if_needed(String *string, size_t capacity)
+{
+    if (string->capacity < capacity) {
+        // Increment the size of the capacity to a multiple of STRING_BLOCK_SIZE.
+        do string->capacity += STRING_BLOCK_SIZE;
+        while (string->capacity < capacity);
+        // Reallocate the needed space. +1 for the null termination.
+        string->text = (char *) realloc(string->text, sizeof(char) * string->capacity + 1);
+    } else if (string->capacity > capacity) {
+        // Decrement till it fits the minimun required space.
+        while (string->capacity > capacity + STRING_BLOCK_SIZE) string->capacity -= STRING_BLOCK_SIZE;
+        // Reallocate the needed space. +1 for the null termination.
+        string->text = (char *) realloc(string->text, sizeof(char) * string->capacity + 1);
+    }
+}
+
+String *string_create(char *text)
+{
+    // Allocate memory for the string.
+    String *string = (String *) malloc(sizeof(String));
+
+    // Set the length of the string.
+    string->length = strlen(text);
+
+    // Set the capacity of the string.
+    string->capacity = 0;
+    while (string->capacity < string->length) string->capacity += STRING_BLOCK_SIZE;
+    string->text = (char *) malloc(sizeof(char) * string->capacity + 1);
+
+    // Set the text of the string.
+    strcpy(string->text, text);
+
+    return string;
+}
+
+void string_push(String *dest, char character)
+{
+    // Reallocate the capacity of the string if needed.
+    reallocate_if_needed(dest, ++dest->length);
+
+    // Push the extra character and add the null termination
+    dest->text[dest->length - 1] = character;
+    dest->text[dest->length] = '\0';
+}
+
+char string_pop(String *dest)
+{
+    // Get the char to be poped.
+    char pop = dest->text[--dest->length];
+
+    // Reallocate the capacity of the string if needed.
+    reallocate_if_needed(dest, dest->length);
+
+    // Set the null termination.
+    dest->text[dest->length] = '\0';
+
+    return pop;
+}
+
+void string_add(String *dest, char *text)
+{
+    // Update the length of the string.
+    dest->length += strlen(text);
+
+    // Reallocate the capacity of the string if needed.
+    reallocate_if_needed(dest, dest->length);
+
+    // Append the given text to the string.
+    strcat(dest->text, text);
+}
+
+void string_concat(String *dest, String *src)
+{
+    // Update the length of the string.
+    dest->length += src->length;
+
+    // Reallocate the capacity of the string if needed.
+    reallocate_if_needed(dest, dest->length);
+
+    // Append the given text to the string.
+    strcat(dest->text, src->text);
+}
+
+void string_substring(String *dest, size_t start, size_t finish)
+{
+    // Calculate the result length of the substring.
+    dest->length = finish - start + 1;
+
+    // Allocate memory for the capacity +1 for null termination.
+    char *substring = (char *) malloc(dest->length + 1);
+
+    // Copy the string from the original to the substring.
+    strncpy(substring, dest->text + start, dest->length);
+
+    // Set the null termination.
+    substring[dest->length] = '\0';
+
+    // Reallocate the capacity of the string if needed.
+    reallocate_if_needed(dest, dest->length);
+
+    // Set the result to the string
+    strcpy(dest->text, substring);
+
+    // Delete the substring memory
+    free(substring);
+}
+
+void string_delete(String *dest)
+{
+    // Remove the text from the heap.
+    free(dest->text);
+
+    // Remove the string from the heap.
+    free(dest);
+}

src/string/string.h

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+#ifndef STRING_H
+#define STRING_H
+
+#define STRING_BLOCK_SIZE 20
+
+#include <stdint.h>
+
+// This is the basic string structure
+// The methods are also documented.
+typedef struct {
+    // It stores the basic text of the string.
+    char *text;
+
+    // It stores the length of the string.
+    size_t length;
+
+    // Stores the capacity of the string (the allocated char bytes of space).
+    size_t capacity;
+} String;
+
+// Creates a new string given a text.
+String *string_create(char *text);
+
+// Pushes a character into the string.
+void string_push(String *dest, char character);
+
+// Pushes a character into the string.
+char string_pop(String *dest);
+
+// Adds a text to the string
+void string_add(String *dest, char *text);
+
+// Adds two strings together.
+void string_concat(String *dest, String *src);
+
+// Transforms the string into a substring. start and finish
+// are the indexes, both beeing inclusive.
+void string_substring(String *dest, size_t start, size_t finish);
+
+// Deletes the string and the text memory from the heap.
+void string_delete(String *dest);
+
+#endif