在C中緩衝區的分配

Question

我試圖創建緩衝區來存儲無限大小的符號。

我有這樣的結構：

typedef struct buffer { 
    int bufferSize; 
    int literalSize; 
    int allocatedSize; 
    char *bufferPtr; 
} bufferStruct; 

在我file.h。

我也有功能緩衝：

bufferStruct *BufferInitialize(int size) { 
    bufferStruct *tempBuff; 
    tempBuff = (bufferStruct *)malloc(sizeof(bufferStruct)); 
    if (tempBuff == NULL) { 
     exit(99);  // MEMORY_ERROR 
    } 
    tempBuff->bufferSize = size; 
    tempBuff->literalSize = 0; 
    tempBuff->bufferPtr = NULL; 
    tempBuff->allocatedSize = 0; 

    return (tempBuff); 
} 

int addToBuffer(bufferStruct *buffer, char c) { 
    if (buffer == NULL) { 
     return 99;  // MEMORY_ERROR 
    } 
    if (buffer->allocatedSize > buffer->literalSize) { 
     buffer->bufferPtr[buffer->literalSize++] = c; 
    } else { 
     buffer->bufferPtr = realloc(buffer->bufferPtr, (buffer->allocatedSize + buffer->bufferSize) * sizeof(char)); 
     if (buffer->bufferPtr == NULL) { 
      return 99;  // MEMORY_ERROR 
     } 
     buffer->allocatedSize += buffer->bufferSize; 
     buffer->bufferSize <<= 1; // bS = bS * 2 
     buffer->bufferPtr[buffer->literalSize++] = c; 
    } 
    return 0; 
} 

int bufferDestroy(bufferStruct *buffer) { 
    if (buffer == NULL) { 
     return 99;  // MEMORY_ERROR 
    } 
    free(buffer->bufferPtr); 
    free(buffer); 
    return 0; 
} 

在我file.c我想創建緩衝區：

token *getNextToken(token *tokenT) { 
    token *actualToken = NULL; 
    char *bufferData = NULL; 
    int charFromFile; 
    eState state = stateInit; 

    bufferStruct *bufferT = NULL; 

    while ((charFromFile = fgetc(fp))) {     
     switch (state) { 
      case stateInit: { 
       if (isdigit(charFromFile)) { 
        bufferT = BufferInitialize(8); 
        addToBuffer(bufferT, charFromFile); 
        state = stateInt; 
       } else 
       if (isalpha(charFromFile) || (charFromFile == '_')) { 
        state = stateId; 
        bufferT = BufferInitialize(16); 
        addToBuffer(bufferT, charFromFile); 
       } else 
       if (isspace(charFromFile)) { 
        state = stateInit; 

       ... some more conditions ... it's similar, a lot. 

      case stateInt: { 
       if (isdigit(charFromFile)) { 
        state = stateInt; 
        addToBuffer(bufferT, charFromFile); 
       } else 
       if ((charFromFile == 'e') || (charFromFile == 'E')) { 
        state = stateExp; 
        addToBuffer(bufferT, charFromFile); 
       } else 
       if (charFromFile = '.') { 
        state = stateDouble; 
        addToBuffer(bufferT, charFromFile); 
       } else { 
        bufferData = bufferT->bufferPtr; 
        //strcpy(actualToken->content, bufferData); 
        addToBuffer(bufferT, '\0'); 
        bufferDestroy(bufferT); 
        actualToken->type = tokenInt; 
        return actualToken; 
       } 
      } break; 

       ... other similar cases ... 
      } 
     } 
    } 

問題是，當我試圖做到這一點，視覺工作室給我錯誤：

One or more multiply defined symbols found Also gives me already defined in main.obj for every function I have.

我沒看到wa出去。我究竟做錯了什麼 ？

Answer 1

有你的代碼中的多個問題：

• 你不應該把代碼中的頭文件。功能BufferInitialize不應位於file.h，除非它被定義爲inline。

• 測試while (c = fgetc(fp))是不正確的：您使用的分配作爲測試表達，這是很容易出錯，你至少應該加上括號賦值表達式，並可能測試EOF而不是'\0'：while ((c = fgetc(fp)) != EOF)。此外，c必須定義爲int。發佈實際的代碼，而不是僞代碼。

• 初始化tempBuff->bufferSize到一個潛在的非零值，而allocatedSize是0和緩衝是未分配的。這看起來不正確。

在你的實際代碼中可能有很多問題，我們看不到代碼是什麼，怎麼能告訴你這些問題？總是發佈一個完整的，可編譯的代碼來展示問題。