113 lines
3.5 KiB
C
113 lines
3.5 KiB
C
/*
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txtbuffer.h
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Text buffer for edit or scrollback
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Copyright (C) 2020 Bill Currie <bill@taniwha.org>
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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.
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See the 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:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifndef __QF_txtbuffer_h
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#define __QF_txtbuffer_h
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#include <stdint.h>
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#include <stdlib.h>
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/** \defgroup txtbuffer Text buffers
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\ingroup utils
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*/
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///@{
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/// must be a power of 2
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#define TXTBUFFER_GROW 0x4000
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/** Text buffer implementing efficient editing.
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*/
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typedef struct txtbuffer_s {
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struct txtbuffer_s *next;
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char *text;
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size_t textSize; ///< amount of text in the buffer
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size_t bufferSize; ///< current capacity of the buffer
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size_t gapOffset; ///< beginning of the gap
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size_t gapSize; ///< size of gap. gapSize + textSize == bufferSize
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} txtbuffer_t;
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/** Create a new, empty buffer.
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*/
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txtbuffer_t *TextBuffer_Create (void);
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/** Destroy a buffer, freeing all resources connected to it.
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\param buffer The buffer to destroy.
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*/
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void TextBuffer_Destroy (txtbuffer_t *buffer);
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/** Open a gap for writing at the specified offset.
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Text after the offset is moved to be after the opened gap.
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The buffer is resized as necessary.
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\param buffer The buffer to be updated
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\param offset The offset in the buffer at which to insert the text block
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\param text_len The size of the gap to be opened
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\return Pointr to beginning of gap if successful, 0 if failure
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(offset not valid or out of memory)
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*/
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char *TextBuffer_OpenGap (txtbuffer_t *buffer, size_t offset,
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size_t text_len);
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/** Insert a block of text at the specified offset.
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Text after the offset is moved to be after the inserted block of text.
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The buffer is resized as necessary.
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nul characters are not significant in that they do not mark the end of
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the text to be inserted.
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\param buffer The buffer to be updated
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\param offset The offset in the buffer at which to insert the text block
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\param text The text block to be inserted. May contain nul ('\0')
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characters.
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\param text_len The number of characters to insert.
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\return 1 for success, 0 for failure (offset not valid or out
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of memory)
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*/
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int TextBuffer_InsertAt (txtbuffer_t *buffer, size_t offset,
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const char *text, size_t text_len);
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/** Delete a block of text from the buffer.
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The buffer is not resized. Rather, its capacity before resizing is require
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is increased.
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\param buffer The buffer to be updated
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\param offset The offset of the beginning of the text block to be deleted
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\param len The amount of characters to be deleted. Values larger than
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the amount of text in the buffer beyond the beginning of
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block are truncated to the amount of remaining text. Thus
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using excessivly large values sets the offset to be the
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end of the buffer.
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\return 1 for success, 0 for failure (offset not valid)
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*/
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int TextBuffer_DeleteAt (txtbuffer_t *buffer, size_t offset, size_t len);
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///@}
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#endif//__QF_txtbuffer_h
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