在C中缓冲区的分配

Question

我试图创建缓冲区来存储无限大小的符号。

我有这样的结构：

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

在我file.h。

我也有功能缓冲：

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我想创建缓冲区：

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 ... 
      } 
     } 
    } 

问题是，当我试图做到这一点，视觉工作室给我错误：

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

我没看到wa出去。我究竟做错了什么 ？

Answer 1

有你的代码中的多个问题：

• 你不应该把代码中的头文件。功能BufferInitialize不应位于file.h，除非它被定义为inline。

• 测试while (c = fgetc(fp))是不正确的：您使用的分配作为测试表达，这是很容易出错，你至少应该加上括号赋值表达式，并可能测试EOF而不是'\0'：while ((c = fgetc(fp)) != EOF)。此外，c必须定义为int。发布实际的代码，而不是伪代码。

• 初始化tempBuff->bufferSize到一个潜在的非零值，而allocatedSize是0和缓冲是未分配的。这看起来不正确。

在你的实际代码中可能有很多问题，我们看不到代码是什么，怎么能告诉你这些问题？总是发布一个完整的，可编译的代码来展示问题。