74 lines
1.4 KiB
Plaintext
74 lines
1.4 KiB
Plaintext
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/*
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a brainfuck interpreter
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reference: https://gist.github.com/maxcountryman/1699708
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*/
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// tape, input buffer, and read/write pointer
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const int TAPE_LEN = 65536, BUFFER_LEN = 32768;
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int tape[TAPE_LEN], program[BUFFER_LEN], ptr = 0;
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// read the input program
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void read_program() {
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int i = 0, len = getint();
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while (i < len) {
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program[i] = getch();
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i = i + 1;
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}
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program[i] = 0;
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}
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// interpret the input program
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void interpret(int input[]) {
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int cur_char, loop, i = 0;
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while (input[i]) {
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cur_char = input[i];
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if (cur_char == 62) {
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// '>'
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ptr = ptr + 1;
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}
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else if (cur_char == 60) {
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// '<'
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ptr = ptr - 1;
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}
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else if (cur_char == 43) {
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// '+'
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tape[ptr] = tape[ptr] + 1;
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}
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else if (cur_char == 45) {
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// '-'
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tape[ptr] = tape[ptr] - 1;
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}
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else if (cur_char == 46) {
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// '.'
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putch(tape[ptr]);
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}
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else if (cur_char == 44) {
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// ','
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tape[ptr] = getch();
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}
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else if (cur_char == 93 && tape[ptr]) {
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// ']'
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loop = 1;
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while (loop > 0) {
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i = i - 1;
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cur_char = input[i];
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if (cur_char == 91) {
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// '['
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loop = loop - 1;
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}
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else if (cur_char == 93) {
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// ']'
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loop = loop + 1;
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}
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}
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}
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i = i + 1;
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}
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}
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int main() {
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read_program();
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interpret(program);
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return 0;
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}
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