Simple BrainFck compiler

bfc.c

// Copyright 2016 Gergely Hegedüs
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//    http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static char *source_begin = "#include <stdio.h>\n\
#include <termios.h>\n\
#include <unistd.h>\n\
#include <stdint.h>\n\
\n\
#define REGISTER_COUNT 65536\n\
\n\
#define INC(N) reg[ptr] += N;           // +\n\
#define DEC(N) reg[ptr] -= N;           // -\n\
#define IPTR(N) ptr += N;               // >\n\
#define DPTR(N) ptr -= N;               // <\n\
#define SLOOP while(reg[ptr] != 0) {    // [\n\
#define ELOOP }                         // ]\n\
#define READ scanf(\"%c\", &reg[ptr]);    // ,\n\
#define PRNT printf(\"%c\", reg[ptr]);    // .\n\
\n\
uint8_t reg[REGISTER_COUNT];\n\
uint16_t ptr;\n\
\n\
struct termios disable_icanon_flag();\n\
void bf_main();\n\
\n\
int main()\n\
{\n\
    struct termios oldt = disable_icanon_flag();\n\
\n\
    bf_main();\n\
\n\
    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);\n\
}\n\
\n\
void bf_main()\n\
{\n\
    ptr = 0;\n\
    for (int i = 0; i < REGISTER_COUNT; ++i)\n\
    {\n\
        reg[i] = 0;\n\
    }\n\
\n\
";

static char *source_end = "}\n\
\n\
struct termios disable_icanon_flag()\n\
{\n\
    static struct termios oldt, newt;\n\
\n\
    tcgetattr(STDIN_FILENO, &oldt);\n\
\n\
    newt = oldt;\n\
\n\
    newt.c_lflag &= ~(ICANON);\n\
\n\
    tcsetattr(STDIN_FILENO, TCSANOW, &newt);\n\
\n\
    return oldt;\n\
}\n";

void parse_bf(FILE *ofile, char *ifilename);

int main(int argc, char **argv)
{
    if (argc < 2)
    {
        printf("Please specify source file\n");
        return 1;
    }

    char *ifilename = argv[1];

    int inamelength = strlen(ifilename);
    char intfname[inamelength + 2];
    strcpy(intfname, ifilename);
    strcat(intfname, ".c");

    char *lastdot = strrchr(ifilename, '.');
    int originallength = lastdot - ifilename;
    char binaryfname[originallength];
    strncpy(binaryfname, ifilename, originallength);

    FILE *ofile = fopen(intfname, "w");

    fprintf(ofile, "%s", source_begin);

    parse_bf(ofile, ifilename);

    fprintf(ofile, "%s", source_end);

    fclose(ofile);

    char compilecommand[7 + originallength + 1 + inamelength + 3];
    strcpy(compilecommand, "gcc -o ");
    strncat(compilecommand, binaryfname, originallength);
    strcat(compilecommand, " ");
    strcat(compilecommand, intfname);

    char rmcommand[3 + inamelength + 2];
    strcpy(rmcommand, "rm ");
    strcat(rmcommand, intfname);

    system(compilecommand);
    system(rmcommand);

    return 0;
}

void print_by_op(FILE *ofile, char op, int ctr)
{
    switch (op) {
        case '+':
                fprintf(ofile, "    INC(%d)\n", ctr);
                break;
            case '-':
                fprintf(ofile, "    DEC(%d)\n", ctr);
                break;
            case '>':
                fprintf(ofile, "    IPTR(%d)\n", ctr);
                break;
            case '<':
                fprintf(ofile, "    DPTR(%d)\n", ctr);
                break;
            case '[':
                fprintf(ofile, "    SLOOP\n");
                break;
            case ']':
                fprintf(ofile, "    ELOOP\n");
                break;
            case ',':
                fprintf(ofile, "    READ\n");
                break;
            case '.':
                fprintf(ofile, "    PRNT\n");
                break;
    }
}

void parse_bf(FILE *ofile, char *ifilename)
{
    FILE *ifile = fopen(ifilename, "r");
    char c, prevc = 0;
    int ctr = 0;

    while ((c = fgetc(ifile)) != EOF)
    {
        if (prevc == c)
        {
            if (prevc == '+' || prevc == '-' || prevc == '>' || prevc == '<')
            {
                ctr++;
            }
            else
            {
                print_by_op(ofile, prevc, 0);
            }
        }
        else
        {
            print_by_op(ofile, prevc, ctr);
            ctr = 1;
        }

        prevc = c;
    }

    print_by_op(ofile, prevc, ctr + 1);
}