readline.cpp
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:6k
- /* Copyright (C) 2000 MySQL AB
- 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 the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /* readline for batch mode */
- #include <my_global.h>
- #include <my_sys.h>
- #include <m_string.h>
- #include "my_readline.h"
- static bool init_line_buffer(LINE_BUFFER *buffer,File file,ulong size,
- ulong max_size);
- static bool init_line_buffer_from_string(LINE_BUFFER *buffer,my_string str);
- static uint fill_buffer(LINE_BUFFER *buffer);
- static char *intern_read_line(LINE_BUFFER *buffer,ulong *out_length);
- LINE_BUFFER *batch_readline_init(ulong max_size,FILE *file)
- {
- LINE_BUFFER *line_buff;
- if (!(line_buff=(LINE_BUFFER*)
- my_malloc(sizeof(*line_buff),MYF(MY_WME | MY_ZEROFILL))))
- return 0;
- if (init_line_buffer(line_buff,fileno(file),IO_SIZE,max_size))
- {
- my_free((char*) line_buff,MYF(0));
- return 0;
- }
- return line_buff;
- }
- char *batch_readline(LINE_BUFFER *line_buff)
- {
- char *pos;
- ulong out_length;
- if (!(pos=intern_read_line(line_buff,&out_length)))
- return 0;
- if (out_length && pos[out_length-1] == 'n')
- out_length--; /* Remove 'n' */
- line_buff->read_length=out_length;
- pos[out_length]=0;
- return pos;
- }
- void batch_readline_end(LINE_BUFFER *line_buff)
- {
- if (line_buff)
- {
- my_free((gptr) line_buff->buffer,MYF(MY_ALLOW_ZERO_PTR));
- my_free((char*) line_buff,MYF(0));
- }
- }
- LINE_BUFFER *batch_readline_command(LINE_BUFFER *line_buff, my_string str)
- {
- if (!line_buff)
- if (!(line_buff=(LINE_BUFFER*)
- my_malloc(sizeof(*line_buff),MYF(MY_WME | MY_ZEROFILL))))
- return 0;
- if (init_line_buffer_from_string(line_buff,str))
- {
- my_free((char*) line_buff,MYF(0));
- return 0;
- }
- return line_buff;
- }
- /*****************************************************************************
- Functions to handle buffered readings of lines from a stream
- ******************************************************************************/
- static bool
- init_line_buffer(LINE_BUFFER *buffer,File file,ulong size,ulong max_buffer)
- {
- buffer->file=file;
- buffer->bufread=size;
- buffer->max_size=max_buffer;
- if (!(buffer->buffer = (char*) my_malloc(buffer->bufread+1,
- MYF(MY_WME | MY_FAE))))
- return 1;
- buffer->end_of_line=buffer->end=buffer->buffer;
- buffer->buffer[0]=0; /* For easy start test */
- return 0;
- }
- /*
- init_line_buffer_from_string can be called on the same buffer
- several times. the resulting buffer will contain a
- concatenation of all strings separated by spaces
- */
- static bool init_line_buffer_from_string(LINE_BUFFER *buffer,my_string str)
- {
- uint old_length=(uint)(buffer->end - buffer->buffer);
- uint length= (uint) strlen(str);
- if (!(buffer->buffer= buffer->start_of_line= buffer->end_of_line=
- (char*)my_realloc(buffer->buffer, old_length+length+2,
- MYF(MY_FAE|MY_ALLOW_ZERO_PTR))))
- return 1;
- buffer->end= buffer->buffer + old_length;
- if (old_length)
- buffer->end[-1]=' ';
- memcpy(buffer->end, str, length);
- buffer->end[length]= 'n';
- buffer->end[length+1]= 0;
- buffer->end+= length+1;
- buffer->eof=1;
- buffer->max_size=1;
- return 0;
- }
- /*
- Fill the buffer retaining the last n bytes at the beginning of the
- newly filled buffer (for backward context). Returns the number of new
- bytes read from disk.
- */
- static uint fill_buffer(LINE_BUFFER *buffer)
- {
- uint read_count;
- uint bufbytes= (uint) (buffer->end - buffer->start_of_line);
- if (buffer->eof)
- return 0; /* Everything read */
- /* See if we need to grow the buffer. */
- for (;;)
- {
- uint start_offset=(uint) (buffer->start_of_line - buffer->buffer);
- read_count=(buffer->bufread - bufbytes)/IO_SIZE;
- if ((read_count*=IO_SIZE))
- break;
- buffer->bufread *= 2;
- if (!(buffer->buffer = (char*) my_realloc(buffer->buffer,
- buffer->bufread+1,
- MYF(MY_WME | MY_FAE))))
- return (uint) -1;
- buffer->start_of_line=buffer->buffer+start_offset;
- buffer->end=buffer->buffer+bufbytes;
- }
- /* Shift stuff down. */
- if (buffer->start_of_line != buffer->buffer)
- {
- bmove(buffer->buffer,buffer->start_of_line,(uint) bufbytes);
- buffer->end=buffer->buffer+bufbytes;
- }
- /* Read in new stuff. */
- if ((read_count= my_read(buffer->file, (byte*) buffer->end, read_count,
- MYF(MY_WME))) == MY_FILE_ERROR)
- return read_count;
- DBUG_PRINT("fill_buff", ("Got %d bytes", read_count));
- /* Kludge to pretend every nonempty file ends with a newline. */
- if (!read_count && bufbytes && buffer->end[-1] != 'n')
- {
- buffer->eof = read_count = 1;
- *buffer->end = 'n';
- }
- buffer->end_of_line=(buffer->start_of_line=buffer->buffer)+bufbytes;
- buffer->end+=read_count;
- *buffer->end=0; /* Sentinel */
- return read_count;
- }
- char *intern_read_line(LINE_BUFFER *buffer,ulong *out_length)
- {
- char *pos;
- uint length;
- DBUG_ENTER("intern_read_line");
- buffer->start_of_line=buffer->end_of_line;
- for (;;)
- {
- pos=buffer->end_of_line;
- while (*pos != 'n' && *pos)
- pos++;
- if (pos == buffer->end)
- {
- if ((uint) (pos - buffer->start_of_line) < buffer->max_size)
- {
- if (!(length=fill_buffer(buffer)) || length == (uint) -1)
- DBUG_RETURN(0);
- continue;
- }
- pos--; /* break line here */
- }
- buffer->end_of_line=pos+1;
- *out_length=(ulong) (pos + 1 - buffer->eof - buffer->start_of_line);
- DBUG_RETURN(buffer->start_of_line);
- }
- }