mirror of
https://github.com/MacPaw/XADMaster.git
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347 lines
7.7 KiB
Objective-C
347 lines
7.7 KiB
Objective-C
/*
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* CSInputBuffer.m
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*
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* Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#import "CSInputBuffer.h"
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// Allocation and management
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CSInputBuffer *CSInputBufferAlloc(CSHandle *parent,int size)
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{
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CSInputBuffer *self=malloc(sizeof(CSInputBuffer)+size);
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if(!self) return NULL;
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self->parent=[parent retain];
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self->startoffs=[parent offsetInFile];
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self->eof=NO;
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self->buffer=(uint8_t *)&self[1];
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self->bufsize=size;
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self->bufbytes=0;
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self->currbyte=0;
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self->bits=0;
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self->numbits=0;
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return self;
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}
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CSInputBuffer *CSInputBufferAllocWithBuffer(const uint8_t *buffer,int length,off_t startoffs)
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{
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CSInputBuffer *self=malloc(sizeof(CSInputBuffer));
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if(!self) return NULL;
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self->parent=NULL;
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self->startoffs=-startoffs;
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self->eof=YES;
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self->buffer=(uint8_t *)buffer; // Since eof is set, the buffer won't be written to.
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self->bufsize=length;
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self->bufbytes=length;
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self->currbyte=0;
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self->bits=0;
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self->numbits=0;
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return self;
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}
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CSInputBuffer *CSInputBufferAllocEmpty()
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{
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CSInputBuffer *self=malloc(sizeof(CSInputBuffer));
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if(!self) return NULL;
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self->parent=NULL;
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self->startoffs=0;
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self->eof=YES;
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self->buffer=NULL;
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self->bufsize=0;
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self->bufbytes=0;
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self->currbyte=0;
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self->bits=0;
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self->numbits=0;
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return self;
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}
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void CSInputBufferFree(CSInputBuffer *self)
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{
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if(self) [self->parent release];
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free(self);
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}
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void CSInputSetMemoryBuffer(CSInputBuffer *self,uint8_t *buffer,int length,off_t startoffs)
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{
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self->eof=YES;
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self->startoffs=-startoffs;
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self->buffer=buffer;
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self->bufsize=length;
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self->bufbytes=length;
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self->currbyte=0;
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self->bits=0;
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self->numbits=0;
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}
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// Buffer and file positioning
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void CSInputRestart(CSInputBuffer *self)
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{
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CSInputSeekToFileOffset(self,self->startoffs);
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}
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void CSInputFlush(CSInputBuffer *self)
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{
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self->currbyte=self->bufbytes=0;
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self->bits=0;
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self->numbits=0;
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}
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void CSInputSynchronizeFileOffset(CSInputBuffer *self)
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{
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CSInputSeekToFileOffset(self,CSInputFileOffset(self));
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}
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void CSInputSeekToFileOffset(CSInputBuffer *self,off_t offset)
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{
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[self->parent seekToFileOffset:offset];
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self->eof=NO;
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CSInputFlush(self);
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}
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void CSInputSeekToBufferOffset(CSInputBuffer *self,off_t offset)
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{
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CSInputSeekToFileOffset(self,offset+self->startoffs);
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}
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void CSInputSetStartOffset(CSInputBuffer *self,off_t offset)
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{
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self->startoffs=offset;
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}
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off_t CSInputBufferOffset(CSInputBuffer *self)
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{
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return CSInputFileOffset(self)-self->startoffs;
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}
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off_t CSInputFileOffset(CSInputBuffer *self)
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{
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if(self->parent) return [self->parent offsetInFile]-self->bufbytes+self->currbyte;
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else return self->currbyte;
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}
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off_t CSInputBufferBitOffset(CSInputBuffer *self)
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{
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return CSInputBufferOffset(self)*8-(self->numbits&7);
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}
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// Byte reading
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void _CSInputFillBuffer(CSInputBuffer *self)
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{
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int left=_CSInputBytesLeftInBuffer(self);
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if(left>=0) memmove(self->buffer,self->buffer+self->currbyte,left);
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else
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{
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[self->parent skipBytes:-left];
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left=0;
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}
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int actual=[self->parent readAtMost:self->bufsize-left toBuffer:self->buffer+left];
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if(actual==0) self->eof=YES;
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self->bufbytes=left+actual;
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self->currbyte=0;
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}
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// Bitstream reading
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// TODO: clean up and/or make faster
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void _CSInputFillBits(CSInputBuffer *self)
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{
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_CSInputCheckAndFillBuffer(self);
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int numbytes=(32-self->numbits)>>3;
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int left=_CSInputBytesLeftInBuffer(self);
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if(numbytes>left) numbytes=left;
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int startoffset=self->numbits>>3;
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// int shift=24-self->numbits;
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// for(int i=0;i<numbytes;i++)
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// {
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// self->bits|=_CSInputPeekByteWithoutEOF(self,i+startoffset)<<shift;
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// shift-=8;
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// }
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// Commented out as it causes false positives for RAR archives. E.g. "CWCHEAT_0_2_2_REVD.RAR" from test data
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//if(startoffset+numbytes>_CSInputBytesLeftInBuffer(self)) _CSInputBufferRaiseEOF(self);
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switch(numbytes)
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{
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case 4:
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self->bits=
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(_CSInputPeekByteWithoutEOF(self,startoffset)<<24)|
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(_CSInputPeekByteWithoutEOF(self,startoffset+1)<<16)|
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(_CSInputPeekByteWithoutEOF(self,startoffset+2)<<8)|
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_CSInputPeekByteWithoutEOF(self,startoffset+3);
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break;
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case 3:
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self->bits|=(
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(_CSInputPeekByteWithoutEOF(self,startoffset)<<16)|
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(_CSInputPeekByteWithoutEOF(self,startoffset+1)<<8)|
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(_CSInputPeekByteWithoutEOF(self,startoffset+2)<<0)
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)<<(8-self->numbits);
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break;
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case 2:
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self->bits|=(
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(_CSInputPeekByteWithoutEOF(self,startoffset)<<8)|
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(_CSInputPeekByteWithoutEOF(self,startoffset+1)<<0)
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)<<(16-self->numbits);
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break;
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case 1:
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self->bits|=_CSInputPeekByteWithoutEOF(self,startoffset)<<(24-self->numbits);
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break;
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}
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self->numbits+=numbytes*8;
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}
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void _CSInputFillBitsLE(CSInputBuffer *self)
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{
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_CSInputCheckAndFillBuffer(self);
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int numbytes=(32-self->numbits)>>3;
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int left=_CSInputBytesLeftInBuffer(self);
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if(numbytes>left) numbytes=left;
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int startoffset=self->numbits>>3;
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for(int i=0;i<numbytes;i++)
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{
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self->bits|=_CSInputPeekByteWithoutEOF(self,i+startoffset)<<self->numbits;
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self->numbits+=8;
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}
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}
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unsigned int CSInputNextBit(CSInputBuffer *self)
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{
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unsigned int bit=CSInputPeekBitString(self,1);
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CSInputSkipPeekedBits(self,1);
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return bit;
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}
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unsigned int CSInputNextBitLE(CSInputBuffer *self)
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{
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unsigned int bit=CSInputPeekBitStringLE(self,1);
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CSInputSkipPeekedBitsLE(self,1);
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return bit;
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}
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unsigned int CSInputNextBitString(CSInputBuffer *self,int numbits)
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{
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if(numbits==0) return 0;
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unsigned int bits=CSInputPeekBitString(self,numbits);
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CSInputSkipPeekedBits(self,numbits);
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return bits;
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}
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unsigned int CSInputNextBitStringLE(CSInputBuffer *self,int numbits)
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{
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if(numbits==0) return 0;
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unsigned int bits=CSInputPeekBitStringLE(self,numbits);
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CSInputSkipPeekedBitsLE(self,numbits);
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return bits;
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}
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unsigned int CSInputNextLongBitString(CSInputBuffer *self,int numbits)
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{
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if(numbits<=25) return CSInputNextBitString(self,numbits);
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else
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{
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int rest=numbits-25;
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unsigned int bits=CSInputNextBitString(self,25)<<rest;
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return bits|CSInputNextBitString(self,rest);
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}
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}
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unsigned int CSInputNextLongBitStringLE(CSInputBuffer *self,int numbits)
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{
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if(numbits<=25) return CSInputNextBitStringLE(self,numbits);
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else
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{
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int rest=numbits-25;
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unsigned int bits=CSInputNextBitStringLE(self,25);
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return bits|(CSInputNextBitStringLE(self,rest)<<25);
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}
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}
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void CSInputSkipBits(CSInputBuffer *self,int numbits)
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{
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if(numbits<=self->numbits) CSInputSkipPeekedBits(self,numbits);
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else
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{
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int skipbits=numbits-(self->numbits&7);
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CSInputSkipToByteBoundary(self);
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CSInputSkipBytes(self,skipbits>>3);
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if(skipbits&7) CSInputNextBitString(self,skipbits&7);
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}
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}
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void CSInputSkipBitsLE(CSInputBuffer *self,int numbits)
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{
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if(numbits<=self->numbits) CSInputSkipPeekedBitsLE(self,numbits);
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else
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{
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int skipbits=numbits-(self->numbits&7);
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CSInputSkipToByteBoundary(self);
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CSInputSkipBytes(self,skipbits>>3);
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if(skipbits&7) CSInputNextBitStringLE(self,skipbits&7);
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}
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}
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BOOL CSInputOnByteBoundary(CSInputBuffer *self)
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{
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return (self->numbits&7)==0;
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}
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void CSInputSkipToByteBoundary(CSInputBuffer *self)
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{
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self->bits=0;
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self->numbits=0;
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}
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void CSInputSkipTo16BitBoundary(CSInputBuffer *self)
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{
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CSInputSkipToByteBoundary(self);
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if(CSInputBufferOffset(self)&1) CSInputSkipBytes(self,1);
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}
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