236 lines
5.7 KiB
C++
236 lines
5.7 KiB
C++
#ifndef HGL_IO_MEMORY_OUTPUT_STREAM_INCLUDE
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#define HGL_IO_MEMORY_OUTPUT_STREAM_INCLUDE
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#include<hgl/io/OutputStream.h>
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namespace hgl
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{
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namespace io
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{
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/**
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* 内存数据输出流，将数据输出到一个内存块中。
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*/
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class MemoryOutputStream:public OutputStream ///内存数据输出流
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{
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protected:
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uint8 *buf;
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size_t max_size;
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size_t buf_size;
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size_t cur_pos;
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bool one;
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public:
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MemoryOutputStream()
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{
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buf=0;
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max_size=0;
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buf_size=0;
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cur_pos=0;
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one=false;
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}
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virtual ~MemoryOutputStream()
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{
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Close();
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}
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void *GetData()const{return buf;}
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/**
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* 创建一个当前流数据的内存拷贝，此函数需用户自行delete[]
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* @param len 存放数据长度的指针
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* @return 创建好的内存拷贝
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*/
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void *CreateCopyData(uint *len)const
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{
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if(buf_size<=0)
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return(nullptr);
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uint8 *data=new uint8[buf_size+1];
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memcpy(data,buf,buf_size);
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data[buf_size]=0;
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if(len)
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*len=buf_size;
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return data;
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}
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/**
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* 关联一个数据区到当前输出流
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* @param ptr 数据指针
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* @param size 数据长度字节数
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* @param one_instance 是否仅此一份实例(如果是，将由MemoryOutputStream类负责释放)
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* @return 是否成功
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*/
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bool Link(void *ptr,size_t size,bool one_instance=false)
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{
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if(!ptr||!size)
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return(false);
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buf=(uint8 *)ptr;
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buf_size=size;
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max_size=size;
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cur_pos=0;
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one=one_instance;
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return(true);
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}
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/**
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* 更新关联的数据区长度，不复位cur_pos
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* @param ptr 数据指针
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* @param size 数据长度字节数
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* @return 是否成功
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*/
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bool Update(void *ptr,size_t size)
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{
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if(!ptr||!size)
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return(false);
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buf=(uint8 *)ptr;
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buf_size=size;
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max_size=0;
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return(true);
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}
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void Unlink()
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{
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buf=0;
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buf_size=0;
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max_size=0;
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}
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bool Create(int64 size)
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{
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Close();
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if(size<=0)
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return(false);
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buf=(uint8 *)hgl_malloc(size);
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if(!buf)
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return(false);
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one=true;
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cur_pos=0;
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buf_size=size;
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max_size=size;
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return(true);
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}
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void Close() override
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{
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if(buf)
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{
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if(one)
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hgl_free(buf);
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buf=0;
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}
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buf_size=0;
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max_size=0;
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}
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void ClearData()
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{
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cur_pos=0;
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buf_size=0;
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}
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int64 Write(const void *ptr,int64 size) override
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{
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if(!ptr||size<0)
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return(-1);
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if(!buf)
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{
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if(!Create(size))
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return(-1);
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}
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if(cur_pos+size>buf_size)
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{
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if(one)
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{
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buf_size=cur_pos+size;
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if(buf_size>max_size)
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{
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max_size=power_to_2(buf_size);
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buf=(uint8 *)hgl_realloc(buf,max_size);
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}
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}
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else
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size=buf_size-cur_pos;
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}
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if(size<=0)
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return(0);
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memcpy(buf+cur_pos,ptr,size);
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cur_pos+=size;
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return size;
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}
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bool CanRestart()const override{return true;}
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bool CanSeek()const override{return true;}
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bool CanSize()const override{return true;}
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bool Restart() override
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{
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cur_pos=0;
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return(true);
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}
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int64 Seek(int64 off,SeekOrigin so=soBegin) override
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{
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if(!CanSeek())return(-1);
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if(so==soCurrent)
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{
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off+=cur_pos;
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}
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else
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if(so==soEnd)
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{
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off+=buf_size;
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}
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if(off<0||off>=buf_size)
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return(-1);
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cur_pos=off;
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return cur_pos;
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}
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int64 Tell()const override
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{
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return cur_pos;
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}
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int64 GetSize()const override
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{
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return buf_size;
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}
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int64 Available()const override
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{
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return buf_size-cur_pos;
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}
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};//class MemoryOutputStream
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}//namespace io
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}//namespace hgl
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#endif//HGL_IO_MEMORY_OUTPUT_STREAM_INCLUDE
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