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String_iterator tested

/*
  $Id: pa_string.h,v 1.19 2001/02/13 10:50:23 paf Exp $
*/

/*

	String				Chunk0
	======				========
	head--------------->[ptr, size, ...]
	append_here-------->[ptr, size, ...]
						.
						.
						[ptr, size, ...]
	link_row----------->[link to the next chunk]

*/

#ifndef PA_STRING_H
#define PA_STRING_H

#ifdef HAVE_CONFIG_H
#include "pa_config.h"
#endif

#include <stddef.h>

#include "pa_pool.h"
#include "pa_types.h"

#ifndef NO_STRING_ORIGIN
#	define STRING_APPEND_PARAMS const char *src, char *file, uint line
#	define APPEND(src, file, line) real_append(src, file, line)
#else
#	define STRING_APPEND_PARAMS const char *src
#	define APPEND(src, file, line) real_append(src)
#endif

class String_iterator;

class String : public Pooled {
	friend String_iterator;
public:
	enum {
		CR_PREALLOCATED_COUNT=5,
		CR_GROW_PERCENT=60
	};

public:

	String(Pool& apool);
	String(const String& src);
	size_t size() const { return fsize; }
	int used_rows() const { return fused_rows; }
	char *cstr() const;
	String& real_append(STRING_APPEND_PARAMS);
	bool operator == (const String& src) const;
	String& append(const String_iterator& begin, const String_iterator& end);

	uint hash_code() const;

	const Origin& origin() const { return head.rows[0].item.origin; }

private:

	struct Chunk {
		// the number of rows in chunk
		int count;
		union Row {
			// chunk item
			struct {
				const char *ptr;  // pointer to the start of string fragment
				size_t size;  // length of the fragment
				Origin origin;  // origin of this fragment
			} item;
			Chunk *link;  // link to the next chunk in chain
		} rows[CR_PREALLOCATED_COUNT];
		// next rows are here
		Chunk *preallocated_link;
	}
		head;  // the head chunk of the chunk chain

	// next append would write to this record
	Chunk::Row *append_here;
	
	// the address of place where lies address 
	// of the link to the next chunk to allocate
	Chunk::Row *link_row;

private:
	// last chank allocated count
	int curr_chunk_rows;

	// string size
	size_t fsize;

	// used rows in all chunks
	int fused_rows;

private:

	bool chunk_is_full() {
		return append_here == link_row;
	}
	void expand();

private: //disabled

	String& operator = (const String&) { return *this; }

};


class Char_types {
public:
	Char_types();
	void set(char c, int type) { 
		types[static_cast<unsigned int>(c)]=static_cast<char>(type); 
	}
	int get(char c) { 
		return static_cast<int>(types[static_cast<unsigned int>(c)]); 
	}
private:	
	char types[0x100];
};

class String_iterator {
public:
	String_iterator(String& astring);

	void operator ++() { skip(); }
	void operator ++(int) { skip(); }

	int skip_to(Char_types& types);
	bool skip_to(char c);

	bool eof() { return position==0; }

	// current char
	char operator() () const;

protected:
	// home string
	String& string;
	// the row in which we are
	String::Chunk::Row *read_here;
	// position in text, eof when 0 
	const char *position;
	// when read_here reaches this row, move to the next chunk
	String::Chunk::Row *link_row;

protected:

	// advances position by one char
	void skip();
};

#endif