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#ifndef DYNBUF_H__ |
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#define DYNBUF_H__ |
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|
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#include <cstring> |
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#include <cassert> |
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|
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// this is a "buffer" that can grow fast |
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// and is still somewhat space-efficient. |
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// unlike obstacks or other data structures, |
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// it never moves data around. basically, |
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// this is a fast strstream without the overhead. |
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|
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class dynbuf |
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{ |
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struct chunk |
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{ |
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chunk *next; |
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int size; |
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char data[0]; |
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}; |
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|
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char *ptr; |
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int room; |
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int ext; |
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int _size; |
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|
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chunk *first, *last; |
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|
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void _reserve (int size); |
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void clear (); |
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void finish (); |
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|
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public: |
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|
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dynbuf (int initial = 4096, int extend = 16384); |
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~dynbuf (); |
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|
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int size () { return _size + (ptr - last->data); } |
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|
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void linearise (void *data); |
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char *linearise (); |
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|
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char *force (int size) |
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{ |
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if (room < size) |
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_reserve (size); |
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|
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return ptr; |
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} |
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|
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char *alloc (int size) |
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{ |
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char *res = force (size); |
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|
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room -= size; |
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ptr += size; |
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|
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return res; |
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} |
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|
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void fadd (char c) { --room; *ptr++ = c; } |
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void fadd (unsigned char c) { fadd (char (c)); } |
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|
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void add (const void *p, int len) |
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{ |
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memcpy (alloc (len), p, len); |
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} |
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|
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void add (char c) |
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{ |
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if (room < 1) |
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_reserve (1); |
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|
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room--; |
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*ptr++ = c; |
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} |
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|
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void add (const char *s) |
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{ |
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add (s, strlen (s)); |
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} |
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|
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static const int max_sint32_size = 11; |
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static const int max_sint64_size = 20; |
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|
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void add (sint32 i); |
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void add (sint64 i); |
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|
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//TODO |
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//void add_destructive (dynbuf &buf); |
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|
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dynbuf &operator << (char c) { add (c); return *this; } |
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dynbuf &operator << (unsigned char c) { return *this << char (c); } |
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dynbuf &operator << (const char *s) { add (s); return *this; } |
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}; |
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|
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#endif |
