~drizzle-trunk/drizzle/development

/* 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; version 2 of the License.

   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 <drizzled/global.h>

#include <mysys/my_sys.h>

#include <mystrings/m_string.h>

#include "my_readline.h"

using namespace std;

static bool init_line_buffer(LINE_BUFFER *buffer,File file,uint32_t size,

			    uint32_t max_size);

static bool init_line_buffer_from_string(LINE_BUFFER *buffer,char * str);

static size_t fill_buffer(LINE_BUFFER *buffer);

static char *intern_read_line(LINE_BUFFER *buffer,uint32_t *out_length);

LINE_BUFFER *batch_readline_init(uint32_t max_size,FILE *file)

{

  LINE_BUFFER *line_buff;

  if (!(line_buff=(LINE_BUFFER*) malloc(sizeof(*line_buff))))

    return 0;

  memset(line_buff, 0, sizeof(*line_buff));

  if (init_line_buffer(line_buff,fileno(file),IO_SIZE,max_size))

  {

    free(line_buff);

    return 0;

  }

  return line_buff;

}

char *batch_readline(LINE_BUFFER *line_buff)

{

  char *pos;

  uint32_t out_length;

  if (!(pos=intern_read_line(line_buff,&out_length)))

    return 0;

  if (out_length && pos[out_length-1] == '\n')

    if (--out_length && pos[out_length-1] == '\r')  /* Remove '\n' */

      out_length--;                                 /* Remove '\r' */

  line_buff->read_length=out_length;

  pos[out_length]=0;

  return pos;

}

void batch_readline_end(LINE_BUFFER *line_buff)

{

  if (line_buff)

  {

    free(line_buff->buffer);

    free(line_buff);

  }

}

LINE_BUFFER *batch_readline_command(LINE_BUFFER *line_buff, char * str)

{

  if (!line_buff)

  {

    if (!(line_buff=(LINE_BUFFER*) malloc(sizeof(*line_buff))))

      return 0;

    memset(line_buff, 0, sizeof(*line_buff));

  }

  if (init_line_buffer_from_string(line_buff,str))

  {

    free(line_buff);

    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,uint32_t size,uint32_t max_buffer)

{

  buffer->file=file;

  buffer->bufread=size;

  buffer->max_size=max_buffer;

  if (!(buffer->buffer = (char*) malloc(buffer->bufread+1)))

    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,char * str)

{

  uint old_length=(uint)(buffer->end - buffer->buffer);

  uint length= (uint) strlen(str);

  char * tmpptr= (char*)realloc(buffer->buffer, old_length+length+2);

  if (tmpptr == NULL)

    return 1;

  buffer->buffer= buffer->start_of_line= buffer->end_of_line= tmpptr;

  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 size_t fill_buffer(LINE_BUFFER *buffer)

{

  size_t 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*) realloc(buffer->buffer,

                                           buffer->bufread+1)))

      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)

  {

    memmove(buffer->buffer, buffer->start_of_line, (uint) bufbytes);

    buffer->end=buffer->buffer+bufbytes;

  }

  /* Read in new stuff. */

  if ((read_count= my_read(buffer->file, (unsigned char*) buffer->end, read_count,

			   MYF(MY_WME))) == MY_FILE_ERROR)

    return (size_t) -1;

  /* 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,uint32_t *out_length)

{

  char *pos;

  size_t length;

  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 == (size_t) -1)

	  return(0);

	continue;

      }

      pos--;					/* break line here */

    }

    buffer->end_of_line=pos+1;

    *out_length=(uint32_t) (pos + 1 - buffer->eof - buffer->start_of_line);

    return(buffer->start_of_line);

  }

}