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/* Copyright (C) 2004 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 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <assert.h>
#include <glib.h>
#include "myx_qb_library.h"
#define SCRIPT_MAX_LINE_LEN 1024*1024
/*
*----------------------------------------------------------------------
* Reads in and parses a block of the given file. Which block is
* determined by block_num. Block_num 1 will read in and parse the last block
* of the file.
*
* SYNOPSIS
* block_size: measured in bytes
* block_num: determines which block starting from the file-end will be read in;
* eg block_num 1 reads in the last block_size bytes from the file
* block_num 3 reads in the bytes that are between block_size * 3
* and block_size *2
* last_block: this variables will be set to indicate if this is the last-block
* or if there is still at least one block before the current one
*
* DESCRIPTION
*
* RETURN VALUE
*
* NOTES
* We start counting with 1 for Block_num. 1 is the last block of the file.
* Dont supply 0!
* The block may be a bit greater than block_size since we have to
* start and end the block after/before a newline
*----------------------------------------------------------------------
*/
/* copied from myx_log_files.c.
* TODO: should be factored out
*/
#define STEP_SIZE 100
static int find_line_beginning(FILE *fp, bigint *offset, bigint file_size)
{
bigint uoff;
char buffer[STEP_SIZE+1];
char *newline_p= NULL;
int step_size= STEP_SIZE;
int i;
buffer[STEP_SIZE]= '\0';
//assert( (offset*(-1)) <= file_size);
uoff= *offset - STEP_SIZE;
while (!newline_p)
{
char *p;
if (uoff*(-1) > file_size)
{
step_size= (int)(STEP_SIZE - (-1*uoff - file_size));
uoff= -file_size;
newline_p= buffer-1; /* if no newline is found, take the file-beginning as newline */
}
if (fseek(fp, (long)uoff, SEEK_END) )
{
return -1;
}
fread(buffer, 1, step_size, fp);
for (p= buffer,i= 0; *p && i < step_size; p++,i++)
{
if (*p == '\n')
newline_p= p;
}
if (newline_p)
{
bigint ind= newline_p - buffer;
*offset= uoff+ind+1;
}
uoff-= STEP_SIZE;
}
return 0;
}
MYX_SCRIPT_FILE_BLOCK* myx_parse_script_file(const char *filename, int block_size, int block_num, int *last_block)
{
char line[SCRIPT_MAX_LINE_LEN];
FILE *fp;
bigint offset;
int line_no;
bigint bytes_read;
bigint file_size= -1;
MYX_SCRIPT_FILE_BLOCK *script;
g_return_val_if_fail(filename, NULL);
g_return_val_if_fail(block_size > 0, NULL);
g_return_val_if_fail(block_num != 0, NULL);
g_return_val_if_fail(last_block != NULL, NULL);
if ((fp= fopen(filename, "r")) == NULL)
{
return NULL;
}
{ /* seek to correct point (we need to begin after a newline) */
int desired_seek_point= block_size * block_num;
file_size= get_file_size(filename);
offset= (desired_seek_point > file_size) ? file_size: desired_seek_point;
offset *= -1;
if (find_line_beginning(fp,&offset, file_size))
{
fclose (fp);
return NULL;
}
*last_block= (offset == -file_size) ? 1 : 0;
}
if (fseek(fp, (long)offset, SEEK_END) )
{
fclose(fp);
return NULL;
}
script= g_malloc0(sizeof(MYX_SCRIPT_FILE_BLOCK));
script->file_size= file_size;
script->block_num= (int)(file_size/block_size);
bytes_read= 0;
line_no=1; /* we start counting at 1! */
while ( (bytes_read < block_size) && (fgets(line, sizeof(line), fp)) )
{
bytes_read+= strlen(line);
line[strlen(line)-1]= '\0';
script->lines_num++;
script->lines= g_realloc(script->lines, sizeof(char *) * script->lines_num);
script->lines[script->lines_num-1]= g_strdup(line);
line_no++;
}
if (ferror(fp))
{
fclose(fp);
return NULL;
}
fclose(fp);
return script;
}
void myx_free_script_file_block(MYX_SCRIPT_FILE_BLOCK *script)
{
if (script)
{
unsigned int i;
for (i=0; i < script->lines_num; i++)
{
g_free(script->lines[i]);
}
g_free(script->lines);
g_free(script);
}
}
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