1*c56079fbSMatthew Wilber /*****************************************************************************/ 2*c56079fbSMatthew Wilber // StreamBuffer 3*c56079fbSMatthew Wilber // Written by Michael Wilber, OBOS Translation Kit Team 4*c56079fbSMatthew Wilber // 5*c56079fbSMatthew Wilber // StreamBuffer.h 6*c56079fbSMatthew Wilber // 7*c56079fbSMatthew Wilber // This class is for buffering data from a BPositionIO object in order to 8*c56079fbSMatthew Wilber // improve performance for cases when small amounts of data are frequently 9*c56079fbSMatthew Wilber // read from a BPositionIO object. 10*c56079fbSMatthew Wilber // 11*c56079fbSMatthew Wilber // 12*c56079fbSMatthew Wilber // Copyright (c) 2003 OpenBeOS Project 13*c56079fbSMatthew Wilber // 14*c56079fbSMatthew Wilber // Permission is hereby granted, free of charge, to any person obtaining a 15*c56079fbSMatthew Wilber // copy of this software and associated documentation files (the "Software"), 16*c56079fbSMatthew Wilber // to deal in the Software without restriction, including without limitation 17*c56079fbSMatthew Wilber // the rights to use, copy, modify, merge, publish, distribute, sublicense, 18*c56079fbSMatthew Wilber // and/or sell copies of the Software, and to permit persons to whom the 19*c56079fbSMatthew Wilber // Software is furnished to do so, subject to the following conditions: 20*c56079fbSMatthew Wilber // 21*c56079fbSMatthew Wilber // The above copyright notice and this permission notice shall be included 22*c56079fbSMatthew Wilber // in all copies or substantial portions of the Software. 23*c56079fbSMatthew Wilber // 24*c56079fbSMatthew Wilber // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 25*c56079fbSMatthew Wilber // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 26*c56079fbSMatthew Wilber // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 27*c56079fbSMatthew Wilber // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 28*c56079fbSMatthew Wilber // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 29*c56079fbSMatthew Wilber // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 30*c56079fbSMatthew Wilber // DEALINGS IN THE SOFTWARE. 31*c56079fbSMatthew Wilber /*****************************************************************************/ 32*c56079fbSMatthew Wilber 33*c56079fbSMatthew Wilber #ifndef STREAM_BUFFER_H 34*c56079fbSMatthew Wilber #define STREAM_BUFFER_H 35*c56079fbSMatthew Wilber 36*c56079fbSMatthew Wilber #include <DataIO.h> 37*c56079fbSMatthew Wilber 38*c56079fbSMatthew Wilber #define MIN_BUFFER_SIZE 512 39*c56079fbSMatthew Wilber 40*c56079fbSMatthew Wilber class StreamBuffer { 41*c56079fbSMatthew Wilber public: 42*c56079fbSMatthew Wilber StreamBuffer(BPositionIO *pstream, size_t nbuffersize, bool binitialread); 43*c56079fbSMatthew Wilber ~StreamBuffer(); 44*c56079fbSMatthew Wilber 45*c56079fbSMatthew Wilber status_t InitCheck(); 46*c56079fbSMatthew Wilber // Determines whether the constructor failed or not 47*c56079fbSMatthew Wilber 48*c56079fbSMatthew Wilber ssize_t Read(uint8 *pinto, size_t nbytes); 49*c56079fbSMatthew Wilber // copy nbytes from the stream into pinto 50*c56079fbSMatthew Wilber 51*c56079fbSMatthew Wilber bool Seek(off_t position); 52*c56079fbSMatthew Wilber // seek the stream to the given position 53*c56079fbSMatthew Wilber 54*c56079fbSMatthew Wilber private: 55*c56079fbSMatthew Wilber ssize_t ReadStream(); 56*c56079fbSMatthew Wilber // Load the stream buffer from the stream 57*c56079fbSMatthew Wilber 58*c56079fbSMatthew Wilber BPositionIO *fpStream; 59*c56079fbSMatthew Wilber // stream object this object is buffering 60*c56079fbSMatthew Wilber uint8 *fpBuffer; 61*c56079fbSMatthew Wilber // buffered data from fpStream 62*c56079fbSMatthew Wilber size_t fnBufferSize; 63*c56079fbSMatthew Wilber // number of bytes of memory allocated for fpBuffer 64*c56079fbSMatthew Wilber size_t fnLen; 65*c56079fbSMatthew Wilber // number of bytes of actual data in fpBuffer 66*c56079fbSMatthew Wilber size_t fnPos; 67*c56079fbSMatthew Wilber // current position in the buffer 68*c56079fbSMatthew Wilber }; 69*c56079fbSMatthew Wilber 70*c56079fbSMatthew Wilber #endif 71