mirror of
https://github.com/libretro/scummvm.git
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332 lines
8.0 KiB
C++
332 lines
8.0 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program 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
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#include "common/stream.h"
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#include "common/str.h"
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#include "common/util.h"
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namespace Common {
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void WriteStream::writeString(const String &str) {
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write(str.c_str(), str.size());
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}
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MemoryReadStream *ReadStream::readStream(uint32 dataSize) {
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void *buf = malloc(dataSize);
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dataSize = read(buf, dataSize);
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assert(dataSize > 0);
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return new MemoryReadStream((byte *)buf, dataSize, DisposeAfterUse::YES);
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}
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uint32 MemoryReadStream::read(void *dataPtr, uint32 dataSize) {
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// Read at most as many bytes as are still available...
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if (dataSize > _size - _pos) {
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dataSize = _size - _pos;
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_eos = true;
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}
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memcpy(dataPtr, _ptr, dataSize);
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if (_encbyte) {
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byte *p = (byte *)dataPtr;
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byte *end = p + dataSize;
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while (p < end)
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*p++ ^= _encbyte;
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}
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_ptr += dataSize;
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_pos += dataSize;
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return dataSize;
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}
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bool MemoryReadStream::seek(int32 offs, int whence) {
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// Pre-Condition
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assert(_pos <= _size);
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switch (whence) {
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case SEEK_END:
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// SEEK_END works just like SEEK_SET, only 'reversed',
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// i.e. from the end.
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offs = _size + offs;
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// Fall through
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case SEEK_SET:
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_ptr = _ptrOrig + offs;
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_pos = offs;
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break;
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case SEEK_CUR:
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_ptr += offs;
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_pos += offs;
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break;
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}
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// Post-Condition
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assert(_pos <= _size);
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// Reset end-of-stream flag on a successful seek
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_eos = false;
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return true; // FIXME: STREAM REWRITE
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}
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enum {
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LF = 0x0A,
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CR = 0x0D
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};
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char *SeekableReadStream::readLine(char *buf, size_t bufSize) {
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assert(buf != 0 && bufSize > 1);
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char *p = buf;
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size_t len = 0;
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char c = 0;
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// If end-of-file occurs before any characters are read, return NULL
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// and the buffer contents remain unchanged.
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if (eos() || err()) {
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return 0;
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}
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// Loop as long as there is still free space in the buffer,
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// and the line has not ended
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while (len + 1 < bufSize && c != LF) {
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c = readByte();
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if (eos()) {
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// If end-of-file occurs before any characters are read, return
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// NULL and the buffer contents remain unchanged.
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if (len == 0)
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return 0;
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break;
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}
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// If an error occurs, return NULL and the buffer contents
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// are indeterminate.
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if (err())
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return 0;
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// Check for CR or CR/LF
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// * DOS and Windows use CRLF line breaks
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// * Unix and OS X use LF line breaks
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// * Macintosh before OS X used CR line breaks
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if (c == CR) {
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// Look at the next char -- is it LF? If not, seek back
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c = readByte();
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if (err()) {
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return 0; // error: the buffer contents are indeterminate
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}
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if (eos()) {
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// The CR was the last character in the file.
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// Reset the eos() flag since we successfully finished a line
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clearErr();
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} else if (c != LF) {
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seek(-1, SEEK_CUR);
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}
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// Treat CR & CR/LF as plain LF
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c = LF;
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}
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*p++ = c;
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len++;
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}
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// We always terminate the buffer if no error occurred
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*p = 0;
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return buf;
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}
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String SeekableReadStream::readLine() {
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// Read a line
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String line;
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while (line.lastChar() != '\n') {
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char buf[256];
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if (!readLine(buf, 256))
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break;
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line += buf;
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}
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if (line.lastChar() == '\n')
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line.deleteLastChar();
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return line;
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}
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uint32 SubReadStream::read(void *dataPtr, uint32 dataSize) {
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if (dataSize > _end - _pos) {
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dataSize = _end - _pos;
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_eos = true;
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}
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dataSize = _parentStream->read(dataPtr, dataSize);
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_eos |= _parentStream->eos();
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_pos += dataSize;
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return dataSize;
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}
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SeekableSubReadStream::SeekableSubReadStream(SeekableReadStream *parentStream, uint32 begin, uint32 end, DisposeAfterUse::Flag disposeParentStream)
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: SubReadStream(parentStream, end, disposeParentStream),
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_parentStream(parentStream),
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_begin(begin) {
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assert(_begin <= _end);
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_pos = _begin;
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_parentStream->seek(_pos);
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_eos = false;
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}
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bool SeekableSubReadStream::seek(int32 offset, int whence) {
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assert(_pos >= _begin);
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assert(_pos <= _end);
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switch (whence) {
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case SEEK_END:
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offset = size() + offset;
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// fallthrough
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case SEEK_SET:
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_pos = _begin + offset;
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break;
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case SEEK_CUR:
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_pos += offset;
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}
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assert(_pos >= _begin);
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assert(_pos <= _end);
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bool ret = _parentStream->seek(_pos);
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if (ret) _eos = false; // reset eos on successful seek
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return ret;
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}
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BufferedReadStream::BufferedReadStream(ReadStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream)
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: _parentStream(parentStream),
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_disposeParentStream(disposeParentStream),
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_pos(0),
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_bufSize(0),
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_realBufSize(bufSize) {
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assert(parentStream);
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_buf = new byte[bufSize];
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assert(_buf);
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}
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BufferedReadStream::~BufferedReadStream() {
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if (_disposeParentStream)
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delete _parentStream;
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delete[] _buf;
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}
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uint32 BufferedReadStream::read(void *dataPtr, uint32 dataSize) {
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uint32 alreadyRead = 0;
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const uint32 bufBytesLeft = _bufSize - _pos;
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// Check whether the data left in the buffer suffices....
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if (dataSize > bufBytesLeft) {
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// Nope, we need to read more data
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// First, flush the buffer, if it is non-empty
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if (0 < bufBytesLeft) {
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memcpy(dataPtr, _buf + _pos, bufBytesLeft);
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_pos = _bufSize;
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alreadyRead += bufBytesLeft;
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dataPtr = (byte *)dataPtr + bufBytesLeft;
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dataSize -= bufBytesLeft;
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}
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// At this point the buffer is empty. Now if the read request
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// exceeds the buffer size, just satisfy it directly.
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if (dataSize > _bufSize)
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return alreadyRead + _parentStream->read(dataPtr, dataSize);
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// Refill the buffer.
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// If we didn't read as many bytes as requested, the reason
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// is EOF or an error. In that case we truncate the buffer
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// size, as well as the number of bytes we are going to
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// return to the caller.
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_bufSize = _parentStream->read(_buf, _realBufSize);
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_pos = 0;
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if (dataSize > _bufSize)
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dataSize = _bufSize;
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}
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// Satisfy the request from the buffer
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memcpy(dataPtr, _buf + _pos, dataSize);
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_pos += dataSize;
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return alreadyRead + dataSize;
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}
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BufferedSeekableReadStream::BufferedSeekableReadStream(SeekableReadStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream)
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: BufferedReadStream(parentStream, bufSize, disposeParentStream),
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_parentStream(parentStream) {
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}
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bool BufferedSeekableReadStream::seek(int32 offset, int whence) {
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// If it is a "local" seek, we may get away with "seeking" around
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// in the buffer only.
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// Note: We could try to handle SEEK_END and SEEK_SET, too, but
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// since they are rarely used, it seems not worth the effort.
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if (whence == SEEK_CUR && (int)_pos + offset >= 0 && _pos + offset <= _bufSize) {
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_pos += offset;
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} else {
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// Seek was not local enough, so we reset the buffer and
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// just seeks normally in the parent stream.
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if (whence == SEEK_CUR)
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offset -= (_bufSize - _pos);
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_pos = _bufSize;
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_parentStream->seek(offset, whence);
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}
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return true; // FIXME: STREAM REWRITE
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}
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bool MemoryWriteStreamDynamic::seek(int32 offs, int whence) {
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// Pre-Condition
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assert(_pos <= _size);
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switch (whence) {
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case SEEK_END:
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// SEEK_END works just like SEEK_SET, only 'reversed',
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// i.e. from the end.
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offs = _size + offs;
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// Fall through
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case SEEK_SET:
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_ptr = _data + offs;
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_pos = offs;
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break;
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case SEEK_CUR:
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_ptr += offs;
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_pos += offs;
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break;
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}
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// Post-Condition
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assert(_pos <= _size);
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return true; // FIXME: STREAM REWRITE
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}
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} // End of namespace Common
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