lab4

lab4/lab4.c

@@ -0,0 +1,189 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+unsigned int Reverse(unsigned int Size) {
+    return ((Size >> 24) & 0x000000ff) | ((Size >> 8) & 0x0000ff00) | ((Size << 8) & 0x00ff0000) | ((Size << 24) & 0xff000000);
+}
+
+
+typedef union Tag { 
+    char Buffer[12]; 
+    struct TagData{
+        unsigned short int Empty; 
+        unsigned char Version[3];
+        unsigned char Version_1; 
+        unsigned char Version_2; 
+        unsigned char Flags; 
+        unsigned int Size; 
+    } TagData; 
+} TagTag; 
+
+typedef union Frame { 
+    char Buffer[10]; 
+    struct FrameData{
+        unsigned char Name[4]; 
+        unsigned int Size; 
+        unsigned short int Flags; 
+    } FrameData; 
+} FrameTag; 
+
+void Copy(FILE *Input, FILE *Output) { 
+    int Char;
+    while ((Char = getc(Input)) != EOF) { 
+        putc(Char, Output); 
+    }
+}
+
+
+
+void Show(char *FileName) {
+    FILE* File = fopen(FileName, "rb"); 
+    fseek(File, 0, 0); 
+
+    TagTag Tag; 
+    fread(Tag.Buffer + 2, sizeof(char), 10, File); 
+    unsigned int TagSize = Reverse(Tag.TagData.Size); 
+    printf("%sv%d.%d\n", Tag.TagData.Version, Tag.TagData.Version_1, Tag.TagData.Version_2); 
+    while (ftell(File) < TagSize + 10) { 
+        FrameTag Frame; 
+        fread(Frame.Buffer, sizeof(char), 10, File); 
+        if (Frame.FrameData.Name[0] == 0) { 
+            break;
+        }
+        printf("%s: ", Frame.FrameData.Name); 
+        unsigned int FrameSize = Reverse(Frame.FrameData.Size); 
+        unsigned char* FrameContent = malloc(sizeof(char) *FrameSize); 
+        fread(FrameContent, sizeof(char), FrameSize, File); 
+        for (int i = 0; i < FrameSize; ++i) { 
+            printf("%c", FrameContent[i]);
+        }
+        printf("\n"); 
+        free(FrameContent); 
+    }
+    fclose(File); 
+}
+
+void Get(char *FileName, char FrameName[4]) {
+    FILE* File = fopen(FileName, "rb"); 
+
+    TagTag Tag;
+    fread(Tag.Buffer + 2, sizeof(char), 10, File); 
+    unsigned int TagSize = Reverse(Tag.TagData.Size); 
+    while (ftell(File) < TagSize + 10) { 
+        FrameTag Frame; 
+        fread(Frame.Buffer, sizeof(char), 10, File); 
+        unsigned int FrameSize = Reverse(Frame.FrameData.Size); 
+        if (strcmp((char*)Frame.FrameData.Name, FrameName) == 0) { 
+            printf("%s: ", Frame.FrameData.Name); 
+            unsigned char *FrameContent = malloc(sizeof(char) *FrameSize); 
+            fread(FrameContent, sizeof(char), FrameSize, File); 
+            for (int i = 0; i < FrameSize; ++i) {
+                printf("%c", FrameContent[i]); 
+            }
+            printf("\n"); 
+            free(FrameContent); 
+            fclose(File); 
+            return; 
+        }
+        fseek(File, FrameSize, 1); 
+    }
+    fclose(File); 
+}
+
+void Set(char *FileName, char FrameName[4], char *FrameValue) {
+    FILE* File = fopen(FileName, "rb"); 
+    TagTag Tag; 
+    fread(Tag.Buffer + 2, sizeof(char), 10, File); 
+    unsigned int TagSize = Reverse(Tag.TagData.Size), OldFramePosition = 0, OldFrameSize = 0; 
+    while (ftell(File) < TagSize + 10) { 
+        FrameTag Frame; 
+        fread(Frame.Buffer, sizeof(char), 10, File); 
+        unsigned int FrameSize = Reverse(Frame.FrameData.Size); 
+        if (strcmp((char*)Frame.FrameData.Name, FrameName) == 0) {  
+            OldFramePosition = (unsigned int)ftell(File) - 10; 
+            OldFrameSize = FrameSize; 
+            break;
+        }
+        fseek(File, FrameSize, 1); 
+    }
+    unsigned int ValueSize = (unsigned int)strlen(FrameValue), NewTagSize = TagSize - OldFrameSize + ValueSize + 10 * (OldFramePosition != 0); // Ничего интересного, просто новые переменные
+    if (OldFramePosition == 0) { 
+        OldFramePosition = (unsigned int)ftell(File); 
+    }
+    if (ValueSize == 0) { 
+        NewTagSize -= 10; 
+    }
+    FILE* FileCopy = fopen("temp.mp3", "wb"); 
+    fseek(File, 0, 0); 
+    fseek(FileCopy, 0, 0); 
+    Copy(File, FileCopy); 
+    fclose(File); 
+    fclose(FileCopy); 
+
+    FileCopy = fopen("temp.mp3", "rb"); 
+    File = fopen(FileName, "wb"); 
+    Tag.TagData.Size = Reverse(NewTagSize); 
+    fwrite(Tag.Buffer + 2, sizeof(char), 10, File); 
+    fseek(FileCopy, 10, 0); 
+
+    for (int i = 0; i < OldFramePosition - 10; ++i) {
+        int Char = getc(FileCopy); 
+        putc(Char, File);
+    }
+    if (ValueSize > 0) { 
+        FrameTag Frame;
+        for (int i = 0; i < 4; ++i) 
+            Frame.FrameData.Name[i] = FrameName[i]; 
+        Frame.FrameData.Size = Reverse(ValueSize); 
+        Frame.FrameData.Flags = 0; 
+        fwrite(Frame.Buffer, sizeof(char), 10, File); 
+    }
+    fwrite(FrameValue, sizeof(char), ValueSize, File); 
+    fseek(FileCopy, OldFramePosition + 10 + OldFrameSize, 0); 
+    for (int i = (int)ftell(File); i < NewTagSize; ++i) { 
+        int Char = getc(FileCopy); 
+        putc(Char, File); 
+    }
+    printf("New val %s: %s\n", FrameName, FrameValue); 
+    Copy(FileCopy, File); 
+    fclose(File); 
+    fclose(FileCopy);
+    remove("temp.mp3"); 
+}
+
+int main(int argc, char *argv[]) {
+    char *FileName = NULL, *FrameName = NULL, *Value = NULL, ShowFlag = 0, SetFlag = 0, GetFlag = 0; 
+    for (int i = 1; i < argc; i++) { 
+        if (strcmp(argv[i], "--show") == 0) { 
+            ShowFlag = 1; 
+            continue; 
+        }
+        if (argv[i][2] == 'f') { 
+            FileName = strpbrk(argv[i], "=") + 1;
+        }
+        if (argv[i][2] == 'g') { 
+            GetFlag = 1; 
+            FrameName = strpbrk(argv[i], "=") + 1; 
+            continue; 
+        }
+        if (argv[i][2] == 's') { 
+            SetFlag = 1; 
+            FrameName = strpbrk(argv[i], "=") + 1; 
+            continue;
+        }
+        if (argv[i][2] == 'v') { 
+            Value = strpbrk(argv[i], "=") + 1; 
+            continue; 
+        }
+    }
+    if (ShowFlag) {
+        Show(FileName); 
+    }
+    if (GetFlag) {
+        Get(FileName, FrameName); 
+    }
+    if (SetFlag) {
+        Set(FileName, FrameName, Value); 
+    }
+}