LAB4 by Barkalov Oleg

lab4/lab4.c

@@ -0,0 +1,329 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+typedef struct
+{
+    unsigned char id[3];
+    unsigned char version[2];
+    unsigned char flags;
+    unsigned char size[4];
+} Header;
+
+typedef struct
+{
+    unsigned char *id;
+    unsigned char *size;
+    unsigned char *flags;
+    unsigned char *content;
+} Frame;
+
+void clear(Frame *frame);
+long header_size(unsigned char sizearr[]);
+long frame_size(unsigned char sizearr[]);
+void read_(unsigned char *str, long n);
+void get_header();
+Frame *get_frame();
+Frame *init_frame();
+void print(char *p, int n);
+void show();
+int null(char *p, int n);
+void get(const char *q);
+Header *header;
+long pointer;
+FILE *fin;
+
+char *separate(char *str);
+
+void copyf(char buff[], char origin[]);
+void set(const char id[], char val[]);
+
+void print_header();
+void print_frame(Frame *);
+
+char filepath[100];
+
+int main(int argc, char *argv[]) {
+    if (argc > 2) {
+        char * p = separate(argv[1]);
+        if (strcmp(argv[1], "--filepath") == 0) {
+            strcpy(filepath, p);
+        } else {
+            printf("ERROR: no path");
+            return -1;
+        }
+    }
+    fin = fopen(filepath, "r+");
+
+    if (argc < 3)
+    {
+        fprintf(fin, "ERROR: not enough arguments");
+        return -2;
+    }
+    else if (argc == 3)
+    {
+        char *val = separate(argv[2]);
+        if (strcmp(argv[2], "--show") == 0)
+            show();
+        else if (strcmp(argv[2], "--get") == 0)
+            get(val);
+        else {
+            fprintf(fin, "ERROR: 1 arg, not supported");
+            return -3;
+        }
+    }
+    else if (argc == 4)
+    {
+        char * id = separate(argv[2]);
+        char * value = separate(argv[3]);
+        if (strcmp(argv[2], "--set") != 0) {
+            printf("ERROR: no tag selected");
+            return -4;
+        }
+
+        if (strcmp(argv[3], "--value") != 0) {
+            printf("ERROR: no value selected");
+            return -5;
+        }
+
+        set(id, value);
+    }
+    else
+    {
+        fprintf(fin, "ERROR: too many arguments");
+        return -6;
+    }
+
+    fclose(fin);
+    return 0;
+}
+
+void set(const char id[], char val[]) {   
+    Frame * frames[100];
+    get_header(); 
+    Frame * frame; Frame *q;
+    int i = 0;
+    int f = 0;
+    while (pointer < header_size(header->size) && (frame = get_frame())) {
+        if (strcmp(frame->id, id) == 0) {
+            q = frame;
+            f = 1;
+            long fsize = strlen(val) + 1;
+
+            for (int i = 0; i < 4; ++i) {
+                frame->size[3 - i] = fsize % (long)pow(2, 8);
+                fsize /= pow(2, 8);
+            } 
+            char * buff = calloc(strlen(val) + 1, sizeof(char));
+            buff[0] = 0;
+            for (int i = 1; i < strlen(val) + 1; ++i) {
+                buff[i] = val[i - 1];
+            }
+            frame->content = buff;
+        }
+        frames[i++] = frame;
+    }
+
+    if (!f) {
+        printf("tag not found");
+        return ;
+    }
+
+    long size1 = frame_size(q->size);
+    long size2 = strlen(val) + 1;
+    long dsize = size2 - size1;
+    long size = header_size(header->size) + dsize;
+
+
+    fseek(fin, 0, SEEK_SET);
+
+    for (int i = 0; i < 4; ++i) {
+        header->size[3 - i] = size % (long)pow(2, 7);
+        size /= pow(2, 7);
+    }
+    print_header();
+
+    for (int j = 0; j < i; ++j)
+        print_frame(frames[j]);
+    fprintf(fin, "\0");
+ }
+
+
+Frame *get_frame() {
+    Frame *frame = init_frame();
+    read_(frame->id, 4);
+    if (null(frame->id, 4))
+    {
+        return 0;
+    }
+    read_(frame->size, 4);
+    read_(frame->flags, 2);
+
+    long size = frame_size(frame->size);
+
+    unsigned char *str = malloc((size + 1L) * sizeof(unsigned char));
+    read_(str, size);
+    frame->content = str;
+
+    return frame;
+}
+
+
+void show() {
+    get_header();
+    Frame *frame;
+    while (pointer < header_size(header->size) && (frame = get_frame())) {
+        print(frame->id, 4);
+        printf("  %d  ", frame_size(frame->size));
+
+        print(frame->content, frame_size(frame->size));
+        printf("\n");
+        clear(frame);
+    }
+}
+
+void print(char *p, int n)
+{
+    while (n-- > 0)
+    {
+        if (*p)
+            printf("%c", *p);
+        *p++;
+    }
+}
+
+void get(const char *q) {
+    get_header();
+    Frame *frame;
+    while (pointer < header_size(header->size) && (frame = get_frame())) {
+        if (strcmp(frame->id, q) == 0) {
+            print(frame->id, 4);
+            printf("  %d  ", frame_size(frame->size));
+
+            print(frame->content, frame_size(frame->size));
+            printf("\n");
+        }
+        clear(frame);
+    }
+}
+
+void get_header()
+{
+    header = malloc(sizeof(Header));
+    int i;
+    for (i = 0; i < 3; ++i)
+        header->id[i] = fgetc(fin);
+
+    for (i = 0; i < 2; ++i)
+        header->version[i] = fgetc(fin);
+
+    header->flags = fgetc(fin);
+
+    for (i = 0; i < 4; ++i)
+    {
+        header->size[i] = fgetc(fin);
+    }
+}
+
+void read_(unsigned char *str, long n)
+{
+    while (n-- > 0)
+    {
+        *str++ = fgetc(fin);
+        ++pointer;
+    }
+    *str = '\0';
+}
+
+void print_header()
+{
+    int i;
+    for (i = 0; i < 3; ++i)
+        fprintf(fin, "%c", header->id[i]);
+
+    for (i = 0; i < 2; ++i)
+        fprintf(fin, "%c", header->version[i]);
+
+    fprintf(fin, "%c", header->flags);
+
+    for (i = 0; i < 4; ++i)
+        fprintf(fin, "%c", header->size[i]);
+}
+
+void print_frame(Frame *frame)
+{
+    int i;
+    for (i = 0; i < 4; ++i)
+        fprintf(fin, "%c", frame->id[i]);
+
+    for (i = 0; i < 4; ++i)
+    {
+        fprintf(fin, "%c", frame->size[i]);
+    }
+    for (i = 0; i < 2; ++i)
+        fprintf(fin, "%c", frame->flags[i]);
+
+    for (i = 0; i < frame_size(frame->size); ++i)
+        fprintf(fin, "%c", frame->content[i]);
+}
+
+int null(char *p, int n)
+{
+    int f = 1;
+    while (n-- > 0)
+        if (*p++ != 0)
+            f = 0;
+    return f;
+}
+
+
+char *separate(char *str)
+{ //первая часть - str, вторая - separate
+    while (*str != '=' && *str++ != '\0')
+        ;
+
+    if (*str == '\0')
+        return str;
+    else
+        *str = '\0';
+    return ++str;
+}
+
+Frame *init_frame() {   
+    Frame *frame = malloc(sizeof(Frame));
+    frame->id = malloc(5 * sizeof(unsigned char));
+    frame->size = malloc(5 * sizeof(unsigned char));
+    frame->flags = malloc(3 * sizeof(unsigned char));
+    frame->content = malloc(sizeof(unsigned char *));
+    return frame;
+}
+
+void clear(Frame *frame)
+{
+    free(frame->id);
+    free(frame->size);
+    free(frame->flags);
+    free(frame->content);
+    free(frame);
+}
+
+long header_size(unsigned char sizearr[])
+{
+    long size = 0;
+    for (int i = 0; i < 4; ++i)
+    {
+        size += ((sizearr[4 - i - 1]) << 7 * i);
+    }
+    return size;
+}
+
+long frame_size(unsigned char arr[])
+{
+    long size = 0;
+    for (int i = 0; i < 4; ++i)
+    {
+        size += ((arr[4 - i - 1]) << 8 * i);
+    }
+    return size;
+}