165 lines
4.9 KiB
C++
165 lines
4.9 KiB
C++
// This file is part of the uSTL library, an STL implementation.
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//
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// Copyright (c) 2005 by Mike Sharov <msharov@users.sourceforge.net>
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// This file is free software, distributed under the MIT License.
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#include "mistream.h"
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#include "memblock.h"
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#include "ualgo.h"
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#include "umemory.h"
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#include "fstream.h"
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#include <errno.h>
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namespace ustl {
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memblock::memblock (void) noexcept : memlink (), m_Capacity (0) { }
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memblock::memblock (const void* p, size_type n) : memlink (), m_Capacity (0) { assign (p, n); }
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memblock::memblock (size_type n) : memlink (), m_Capacity (0) { resize (n); }
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memblock::memblock (const cmemlink& b) : memlink (), m_Capacity (0) { assign (b); }
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memblock::memblock (const memlink& b) : memlink (), m_Capacity (0) { assign (b); }
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memblock::memblock (const memblock& b) : memlink (), m_Capacity (0) { assign (b); }
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memblock::~memblock (void) noexcept { deallocate(); }
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void memblock::unlink (void) noexcept
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{
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m_Capacity = 0;
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memlink::unlink();
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}
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/// resizes the block to \p newSize bytes, reallocating if necessary.
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void memblock::resize (size_type newSize, bool bExact)
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{
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if (m_Capacity < newSize + minimumFreeCapacity())
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reserve (newSize, bExact);
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memlink::resize (newSize);
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}
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/// Frees internal data.
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void memblock::deallocate (void) noexcept
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{
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if (m_Capacity) {
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assert (cdata() && "Internal error: space allocated, but the pointer is NULL");
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assert (data() && "Internal error: read-only block is marked as allocated space");
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free (data());
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}
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unlink();
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}
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/// Assumes control of the memory block \p p of size \p n.
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/// The block assigned using this function will be freed in the destructor.
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void memblock::manage (void* p, size_type n) noexcept
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{
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assert (p || !n);
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assert (!m_Capacity && "Already managing something. deallocate or unlink first.");
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link (p, n);
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m_Capacity = n;
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}
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/// "Instantiate" a linked block by allocating and copying the linked data.
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void memblock::copy_link (void)
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{
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const pointer p (begin());
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const size_t sz (size());
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if (is_linked())
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unlink();
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assign (p, sz);
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}
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/// Copies data from \p p, \p n.
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void memblock::assign (const void* p, size_type n)
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{
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assert ((p != (const void*) cdata() || size() == n) && "Self-assignment can not resize");
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resize (n);
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copy_n (const_pointer(p), n, begin());
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}
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/// \brief Reallocates internal block to hold at least \p newSize bytes.
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///
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/// Additional memory may be allocated, but for efficiency it is a very
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/// good idea to call reserve before doing byte-by-byte edit operations.
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/// The block size as returned by size() is not altered. reserve will not
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/// reduce allocated memory. If you think you are wasting space, call
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/// deallocate and start over. To avoid wasting space, use the block for
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/// only one purpose, and try to get that purpose to use similar amounts
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/// of memory on each iteration.
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///
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void memblock::reserve (size_type newSize, bool bExact)
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{
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if ((newSize += minimumFreeCapacity()) <= m_Capacity)
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return;
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pointer oldBlock (is_linked() ? NULL : data());
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const size_t alignedSize (NextPow2 (newSize));
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if (!bExact)
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newSize = alignedSize;
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pointer newBlock = (pointer) realloc (oldBlock, newSize);
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if (!newBlock)
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return;
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if (!oldBlock & (cdata() != NULL))
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copy_n (cdata(), min (size() + 1, newSize), newBlock);
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link (newBlock, size());
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m_Capacity = newSize;
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}
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/// Reduces capacity to match size
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void memblock::shrink_to_fit (void)
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{
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if (is_linked())
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return;
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pointer newBlock = (pointer) realloc (begin(), size());
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if (!newBlock && size())
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return;
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m_Capacity = size();
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memlink::relink (newBlock, size());
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}
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/// Shifts the data in the linked block from \p start to \p start + \p n.
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memblock::iterator memblock::insert (const_iterator start, size_type n)
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{
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const uoff_t ip = start - begin();
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assert (ip <= size());
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resize (size() + n, false);
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memlink::insert (iat(ip), n);
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return (iat (ip));
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}
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/// Shifts the data in the linked block from \p start + \p n to \p start.
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memblock::iterator memblock::erase (const_iterator start, size_type n)
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{
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const uoff_t ep = start - begin();
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assert (ep + n <= size());
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reserve (size() - n);
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iterator iep = iat(ep);
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memlink::erase (iep, n);
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memlink::resize (size() - n);
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return (iep);
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}
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/// Reads the object from stream \p s
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void memblock::read (istream& is)
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{
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written_size_type n = 0;
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is >> n;
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if (!is.verify_remaining ("read", "ustl::memblock", n))
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return;
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resize (n);
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is.read (data(), writable_size());
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is.align (stream_align_of (n));
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}
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/// Reads the entire file \p "filename".
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void memblock::read_file (const char* filename)
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{
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fstream f;
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f.exceptions (fstream::allbadbits);
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f.open (filename, fstream::in);
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const off_t fsize (f.size());
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reserve (fsize);
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f.read (data(), fsize);
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f.close();
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resize (fsize);
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}
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memblock::size_type memblock::minimumFreeCapacity (void) const noexcept { return (0); }
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} // namespace ustl
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