/* txtbuffer.h Text buffer for edit or scrollback Copyright (C) 2020 Bill Currie This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to: Free Software Foundation, Inc. 59 Temple Place - Suite 330 Boston, MA 02111-1307, USA */ #ifndef __QF_txtbuffer_h #define __QF_txtbuffer_h #include #include /** \defgroup txtbuffer Text buffers \ingroup utils */ ///@{ /// must be a power of 2 #define TXTBUFFER_GROW 0x4000 /** Text buffer implementing efficient editing. */ typedef struct txtbuffer_s { struct txtbuffer_s *next; char *text; size_t textSize; ///< amount of text in the buffer size_t bufferSize; ///< current capacity of the buffer size_t gapOffset; ///< beginning of the gap size_t gapSize; ///< size of gap. gapSize + textSize == bufferSize } txtbuffer_t; /** Create a new, empty buffer. */ txtbuffer_t *TextBuffer_Create (void); /** Destroy a buffer, freeing all resources connected to it. \param buffer The buffer to destroy. */ void TextBuffer_Destroy (txtbuffer_t *buffer); /** Open a gap for writing at the specified offset. Text after the offset is moved to be after the opened gap. The buffer is resized as necessary. \param buffer The buffer to be updated \param offset The offset in the buffer at which to insert the text block \param text_len The size of the gap to be opened \return Pointr to beginning of gap if successful, 0 if failure (offset not valid or out of memory) */ char *TextBuffer_OpenGap (txtbuffer_t *buffer, size_t offset, size_t text_len); /** Insert a block of text at the specified offset. Text after the offset is moved to be after the inserted block of text. The buffer is resized as necessary. nul characters are not significant in that they do not mark the end of the text to be inserted. \param buffer The buffer to be updated \param offset The offset in the buffer at which to insert the text block \param text The text block to be inserted. May contain nul ('\0') characters. \param text_len The number of characters to insert. \return 1 for success, 0 for failure (offset not valid or out of memory) */ int TextBuffer_InsertAt (txtbuffer_t *buffer, size_t offset, const char *text, size_t text_len); /** Delete a block of text from the buffer. The buffer is not resized. Rather, its capacity before resizing is require is increased. \param buffer The buffer to be updated \param offset The offset of the beginning of the text block to be deleted \param len The amount of characters to be deleted. Values larger than the amount of text in the buffer beyond the beginning of block are truncated to the amount of remaining text. Thus using excessivly large values sets the offset to be the end of the buffer. \return 1 for success, 0 for failure (offset not valid) */ int TextBuffer_DeleteAt (txtbuffer_t *buffer, size_t offset, size_t len); ///@} #endif//__QF_txtbuffer_h