path: root/src/execute.c

/* 
 *    bbe - Binary block editor
 *
 *    Copyright (C) 2005 Timo Savinen
 *    This file is part of bbe.
 * 
 *    bbe 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.
 *
 *    bbe 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 bbe; if not, write to the Free Software
 *    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/* $Id: execute.c,v 1.38 2006-03-12 10:05:33 timo Exp $ */

#include "bbe.h"
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <ctype.h>

/* tells if current byte should be deleted */
static int delete_this_byte;

/* tells if current block should be deleted */
static int delete_this_block;

/* tells if current block should be skipped */
static int skip_this_block;

/* tells if i or s commands are inserting bytes, meaningfull at end of the block */
static int inserting;

/* tells if there is w-command with file having %d 
   this is only for performance 
   */
static int w_commands_block_num = 0;

/* command list for write_w_command */
static struct command_list *current_byte_commands;

/* most significant bit of byte */
#define BYTE_MASK (1 << (sizeof(unsigned char) * 8 - 1))

 
/* byte_to_string, convert byte value to visible string,
   either hex (H), decimal (D), octal (O) or ascii (A)
   */
char *
byte_to_string(unsigned char byte,char format)
{
    static char string[128];
    int i;

    switch(format)
    {
        case 'H':
            sprintf(string,"x%02x",(int) byte);
            break;
        case 'D':
            sprintf(string,"%3d",(int) byte);
            break;
        case 'O':
            sprintf(string,"%03o",(int) byte);
            break;
        case 'A':
            sprintf(string,"%c",isprint(byte) ? byte : ' ');
            break;
        case 'B':
            i = 0;
            do
            {
                string[i] = ((BYTE_MASK >> i) & byte) ? '1' : '0';
                i++;
            } while (BYTE_MASK >> i);
            string[i] = 0;
            break;
        default:
            string[0] = 0;
            break;
    }
    return string;
}

/* convert off_t to string  */
char *
off_t_to_string(off_t number,char format)
{
    static char string[128];

    switch(format)
    {
        case 'H':
             sprintf(string,"x%llx",(long long) number);
             break;
        case 'D':
             sprintf(string,"%lld",(long long) number);
             break;
        case 'O':
             sprintf(string,"0%llo",(long long) number);
             break;
        default:
             string[0] = 0;
             break;
    }
    return string;
}



#define IO_BLOCK_SIZE (8 * 1024)

/* execute given commands */
void
execute_commands(struct command_list *c)
{
    register int i;
    unsigned char a,b;
    unsigned char *p;
    char *str;
    off_t read_count;
    static unsigned char ioblock[IO_BLOCK_SIZE];

    if(skip_this_block) return;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case 'A':
            case 'I':
                write_buffer(c->s1,c->s1_len);
                break;
            case 'd':
                if(c->rpos || c->offset == in_buffer.block_offset) 
                {
                    if(c->rpos < c->count || c->count == 0)
                    {
                        if(inserting)
                        {
                            inserting = 0;
                        } else
                        {
                             delete_this_byte = 1;
                        }
                        c->rpos++;
                    } else
                    {
                        c->rpos = 0;
                    }
                }
                break;
            case 'D':
                if(c->offset == in_buffer.block_num || c->offset == 0) delete_this_block = 1;
                break;
            case 'i':
                if(c->offset == in_buffer.block_offset && !c->rpos) 
                {
                    c->rpos = 1;
                    inserting = 1;
                    break;
                } 
                if(c->rpos > 0 && c->rpos <= c->s1_len)
                {
                    if(c->rpos <= c->s1_len)
                    {
                        put_byte(c->s1[c->rpos - 1]);
                        if(delete_this_byte)
                        {
                            delete_this_byte = 0;
                        } else 
                        {
                            if(c->rpos < c->s1_len) inserting = 1;
                        }
                    }
                    c->rpos++;
                }
                break;
            case 'r':
                if(in_buffer.block_offset >= c->offset &&
                        in_buffer.block_offset < c->offset + c->s1_len)
                {
                    put_byte(c->s1[in_buffer.block_offset - c->offset]);
                }
                break;
            case 's':
                if(c->rpos)
                {
                    if(c->rpos < c->s1_len && c->rpos < c->s2_len)
                    {
                        put_byte(c->s2[c->rpos]);
                    } else if (c->rpos < c->s1_len && c->rpos >= c->s2_len)
                    {
                        if(inserting)
                        {
                            inserting = 0;
                        } else
                        {
                            delete_this_byte = 1;
                        }
                    } else if(c->rpos >= c->s1_len && c->rpos < c->s2_len)
                    {
                        put_byte(c->s2[c->rpos]);
                    } 

                        if(c->rpos >= c->s1_len - 1 && c->rpos < c->s2_len - 1)
                        {
                            if(delete_this_byte)
                            {
                                delete_this_byte = 0;
                            } else
                            {
                                inserting = 1;
                            }
                        }

                        c->rpos++;
                        if(c->rpos >= c->s1_len && c->rpos >= c->s2_len)
                        {
                            c->rpos = 0;
                        }
                        break;
                }
                if(delete_this_byte) break;
                if(c->fpos == in_buffer.block_offset) break;
                p = out_buffer.write_pos;
                i = 0;
                while(*p == c->s1[i] && i < c->s1_len)
                {
                    if(p == out_buffer.write_pos) p = read_pos();
                    if(p == block_end_pos() && c->s1_len - 1 > i) break;
                    i++;
                    p++;
                }
                if(i == c->s1_len) 
                {
                    c->fpos = in_buffer.block_offset;
                    if(c->s1_len > 1 || c->s2_len > 1) c->rpos = 1;
                    if(c->s2_len) 
                    {
                        put_byte(c->s2[0]);
                        if(delete_this_byte)
                        {
                            delete_this_byte = 0;
                        } else
                        {
                            if(c->s1_len == 1 && c->s2_len > 1) inserting = 1;
                        }
                    } else
                    {
                        if(inserting)
                        {
                            inserting = 0;
                        } else
                        {
                            delete_this_byte = 1;
                        }
                    }
                }
                break;
            case 'y':
                i = 0;
                while(c->s1[i] != *out_buffer.write_pos && i < c->s1_len) i++;
                if(c->s1[i] == *out_buffer.write_pos && i < c->s1_len) put_byte(c->s2[i]);
                break;
            case 'c':
                switch(c->s1[0])
                {
                    case 'A':                   // from ascii
                        switch(c->s1[3])
                        {
                            case 'B':           // to bcd
                                if(c->rpos || (last_byte() && out_buffer.block_offset == 0))     // skip first nibble
                                {
                                    c->rpos = 0;
                                    if(last_byte())  // unless last byte of block
                                    {
                                        if(*out_buffer.write_pos >= '0' && *out_buffer.write_pos <= '9') 
                                        {
                                            a = *out_buffer.write_pos - '0';
                                            a = (a << 4) & 0xf0;
                                            b = 0x0f;
                                            *out_buffer.write_pos = a | b;
                                        }
                                    }
                                    break;
                                }
                                if(out_buffer.block_offset == 0 || delete_this_byte) break;
                                if((out_buffer.write_pos[-1] >= '0' && out_buffer.write_pos[-1] <= '9'))
                                {
                                    a = out_buffer.write_pos[-1] - '0';
                                    a = (a << 4) & 0xf0;
                                    if(*out_buffer.write_pos >= '0' && *out_buffer.write_pos <= '9')
                                    {
                                        b = *out_buffer.write_pos - '0';
                                        b &= 0x0f;
                                        delete_this_byte = 1;
                                        c->rpos = 1;
                                    } else
                                    {
                                        b = 0x0f;
                                        if(*out_buffer.write_pos == 'F' || *out_buffer.write_pos == 'f') delete_this_byte=1;
                                    }
                                    out_buffer.write_pos[-1] = a | b;
                                }
                                break;
                        }
                        break;
                    case 'B':               // from bcd
                        switch(c->s1[3])
                        {
                            case 'A':       // to ascii
                                if(((*out_buffer.write_pos >> 4) & 0x0f) <= 9 && 
                                        ((*out_buffer.write_pos & 0x0f) <= 9 || (*out_buffer.write_pos & 0x0f) == 0x0f))
                                {
                                    a = (*out_buffer.write_pos >> 4) & 0x0f;
                                    b = *out_buffer.write_pos & 0x0f;
                                    *out_buffer.write_pos = '0' + a;
                                    if(!delete_this_byte) 
                                    {
                                        write_next_byte();
                                        if(b == 0x0f)
                                        {
                                            *out_buffer.write_pos = 'F';
                                        } else
                                        {
                                            *out_buffer.write_pos = '0' + b;
                                        }
                                    }
                                }
                                break;
                        }
                        break;
                }
                break;
            case 'j':
                if(in_buffer.block_offset < c->count)
                {
                    while(c->next != NULL) c = c->next;     // skip rest of commands
                }
                break;
            case 'J':
                if(in_buffer.block_num <= c->count)
                {
                    skip_this_block = 1;
                    return;
                }
                break;
            case 'l':
                if(in_buffer.block_offset >= c->count)
                {
                    while(c->next != NULL) c = c->next;     // skip rest of commands
                }
                break;
            case 'L':
                if(in_buffer.block_num > c->count)
                {
                    skip_this_block = 1;
                    return;
                }
                break;
            case 'p':
                if (delete_this_byte) break;
                i = 0;
                a = *out_buffer.write_pos;
                while(i < c->s1_len)
                {
                    str = byte_to_string(a,c->s1[i]);
                    write_string(str);
                    i++;
                    if (i < c->s1_len) 
                    {
                        put_byte('-');
                        write_next_byte();
                    }
                }
                put_byte(' ');
                break;
            case 'F':
                str = off_t_to_string(in_buffer.stream_offset + (off_t) (in_buffer.read_pos-in_buffer.buffer),c->s1[0]);
                write_string(str);
                put_byte(':');
                write_next_byte();
                break;
            case 'B':
                str = off_t_to_string(in_buffer.block_num,c->s1[0]);
                write_string(str);
                put_byte(':');
                write_next_byte();
                break;
            case 'N':
                write_string(get_current_file());
                put_byte(':');
                write_next_byte();
                break;
            case '&':
                put_byte(*out_buffer.write_pos & c->s1[0]);
                break;
            case '|':
                put_byte(*out_buffer.write_pos | c->s1[0]);
                break;
            case '^':
                put_byte(*out_buffer.write_pos ^ c->s1[0]);
                break;
            case '~':
                put_byte(~*out_buffer.write_pos);
                break;
            case '<':
            case '>':
                if (fseeko(c->fd,0,SEEK_SET)) panic("Cannot seek file",c->s1,strerror(errno));
                do
                {
                    read_count = fread(ioblock,1,IO_BLOCK_SIZE,c->fd);
                    write_buffer(ioblock,read_count);
                } while(read_count);
                break;
            case 'u':
                if(in_buffer.block_offset <= c->offset)
                {
                    put_byte(c->s1[0]);
                }
                break;
            case 'f':
                if(in_buffer.block_offset >= c->offset)
                {
                    put_byte(c->s1[0]);
                }
                break;
            case 'w':
                break;
            case 'x':
                put_byte(((*out_buffer.write_pos << 4) & 0xf0) | ((*out_buffer.write_pos >> 4) & 0x0f));
                break;
        }
        c = c->next;
    }
}

/* write w command, will be called when output_buffer is written, same will be written to w-command files */
void
write_w_command(unsigned char *buf,size_t length)
{
    struct command_list *c;

    if(skip_this_block) return;

    c = current_byte_commands;

    while(c != NULL)
    {
        if(c->letter == 'w')
        {
            if(fwrite(buf,1,length,c->fd) != length) panic("Cannot write to file",c->s2,strerror(errno));
            if(length) c->count = 1;    // file was written
        }
        c = c->next;
    }
}

/* finds the %B or %nB format string from the filename of w-command 
   returns pointer to %-postion and the length of the format string
   */
char *
find_block_w_file(char *file,int *len)
{
    char *f,*ppos;

    f = file;

    while(*f != 0)
    {
        if(*f == '%')
        {
            ppos = f;
            f++;
            while(f - ppos < 4 && isdigit(*f)) f++;
            if(*f == 'B')
            {
                *len = (int) (f - ppos) + 1;
                return ppos;
            }
            f = ppos;
        }
        f++;
    }
    return NULL;
}

/* replaces all %B or %nB format strings with block number in a file name */
void
bn_printf(char *file,char *str,off_t block_number)
{
    char *bstart,*f;
    char num[128],format[64];
    int blen;

    f = str;
    file[0] = 0;

    while((bstart = find_block_w_file(f,&blen)) != NULL)
    {
        num[0] = 0;
        format[0] = 0;
        strncat(file,f,bstart - f);
        strncpy(format,bstart,blen-1);
        format[blen-1] = 0;
        strcat(format,"lld");
        sprintf(num,format,(long long) block_number);
        if(strlen(file) + strlen(num) >= 4096) panic("Filename for w-command too long",str,NULL);
        strcat(file,num);
        f = bstart + blen;
    }
    strcat(file,f);
}

/* close (if open) and open next w-command files for new block */
void
open_w_files(off_t block_number)
{
    struct command_list *c;
    static char file[4096];

    c = current_byte_commands;

    while(c != NULL)
    {
        if(c->letter == 'w' && c->offset)
        {
            if(c->fd != NULL) 
            {
                if(fclose(c->fd) != 0) panic("Error closing file",c->s2,strerror(errno));
                if (!c->count && c->s2 != NULL)  // remove if empty
                {
                    unlink(c->s2);
                }
                c->fd = NULL;
            }

            bn_printf(file,c->s1,block_number);
            c->fd = fopen(file,"w");
            if(c->fd == NULL) panic("Cannot open file for writing",file,strerror(errno));
            c->count = 0;
            if(c->s2 != NULL) free(c->s2);
            c->s2 = xstrdup(file);
        }
        c = c->next;
    }
}

                

/* init_commands, initialize those wich need it, currently w - open file and rpos=0 for all */
void
init_commands(struct commands *commands)
{
    struct command_list *c;
    int wlen;

    c = commands->byte;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case 'w':
                if(find_block_w_file(c->s1,&wlen) != NULL)
                {
                    c->fd = NULL;
                    c->offset = 1;
                    w_commands_block_num = 1;
                    c->s2 = NULL;
                } else
                {
                    c->fd = fopen(c->s1,"w");
                    if(c->fd == NULL) panic("Cannot open file for writing",c->s1,strerror(errno));
                    c->offset = 0;
                    c->s2 = xstrdup(c->s1);
                }
                c->count = 0;
                break;
        }
        c = c->next;
    }

    c = commands->block_start;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case '>':
                c->fd = fopen(c->s1,"r");
                if(c->fd == NULL) panic("Cannot open file for reading",c->s1,strerror(errno));
                break;
        }
        c = c->next;
    }

    c = commands->block_end;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case '<':
                c->fd = fopen(c->s1,"r");
                if(c->fd == NULL) panic("Cannot open file for reading",c->s1,strerror(errno));
                break;
        }
        c = c->next;
    }
    
}


/* close_commands, close those wich need it, currently w - close file */
void
close_commands(struct commands *commands)
{
    struct command_list *c;

    c = commands->byte;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case 'w':
                if(c->fd != NULL)
                {
                    if(fclose(c->fd) != 0) panic("Error in closing file",c->s2,strerror(errno));
                    if(!c->count && c->s2 != NULL)
                    {
                        unlink(c->s2);
                    }
                }
                break;
        }
        c = c->next;
    }

    c = commands->block_start;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case '>':
                fclose(c->fd);
                break;
        }
        c = c->next;
    }

    c = commands->block_end;

    while(c != NULL)
    {
        switch(c->letter)
        {
            case '<':
                fclose(c->fd);
                break;
        }
        c = c->next;
    }
}

/* reset the rpos counter for next block, in case block was shorter eg. delete count */
inline void
reset_rpos(struct command_list *c)
{
    while(c != NULL)
    {
        c->rpos = 0;
        c->fpos = -1;
        c = c->next;
    }
}



/* main execution loop */
void
execute_program(struct commands *commands)
{
    int block_end;

    current_byte_commands = commands->byte;

    while(find_block())
    {
        reset_rpos(commands->byte);
        delete_this_block = 0;
        out_buffer.block_offset = 0;
        skip_this_block = 0;
        if(w_commands_block_num) open_w_files(in_buffer.block_num);
        execute_commands(commands->block_start);
        do
        {
            delete_this_byte = 0;
            inserting = 0;
            block_end = last_byte();
            put_byte(read_byte());     // as default write current byte from input
            execute_commands(commands->byte);
            if(!delete_this_byte && !delete_this_block)
            {
               write_next_byte();           // advance the write pointer if byte is not marked for del
            }
            if(!block_end && !inserting) get_next_byte();
        } while (!block_end || inserting);
        execute_commands(commands->block_end);
        flush_buffer();
    }
    close_output_stream();
}