| 1 | /* |
| 2 | * (c) 2019 Aaron Taylor <ataylor at subgeniuskitty dot com> |
| 3 | * All rights reserved. |
| 4 | */ |
| 5 | |
| 6 | #include <stdio.h> |
| 7 | #include <stdlib.h> |
| 8 | #include <unistd.h> |
| 9 | #include <string.h> |
| 10 | #include <errno.h> |
| 11 | #include <getopt.h> |
| 12 | #include <stdint.h> |
| 13 | |
| 14 | #define VERSION 1 |
| 15 | |
| 16 | void |
| 17 | print_usage(char ** argv) |
| 18 | { |
| 19 | printf( "VVhitespace Interpreter v%d (www.subgeniuskitty.com)\n" |
| 20 | "Usage: %s -i <file> -o <file>\n" |
| 21 | " -h Help (prints this message)\n" |
| 22 | " -i <file> Specify a pseudo-VVhitespace source file as input.\n" |
| 23 | " -o <file> Specify location for VVhitespace output.\n" |
| 24 | , VERSION, argv[0] |
| 25 | ); |
| 26 | } |
| 27 | |
| 28 | /* Builds an ASCII string on the stack using VVS PUSH_IMMEDIATE commands. */ |
| 29 | /* The syntax: A"test" results in five PUSH_IMMEDIATE commands for the four */ |
| 30 | /* letters, and null-terminator. */ |
| 31 | /* Expects 'input' to present a double-quoted ('"') ASCII string. */ |
| 32 | /* The 'A' has already been chomped. */ |
| 33 | void |
| 34 | parse_ascii_string(FILE * input, FILE * output) |
| 35 | { |
| 36 | uint8_t temp_byte; |
| 37 | fread(&temp_byte, 1, 1, input); |
| 38 | if (temp_byte != '"') { |
| 39 | /* Die here since we walk the string backward and look for '"' as a terminator. */ |
| 40 | fprintf(stderr, "ERROR: Expected double-quote to begin string.\n"); |
| 41 | exit(EXIT_FAILURE); |
| 42 | } |
| 43 | |
| 44 | /* Put the letters on the stack in reverse. Don't forget to put a null-terminator first. */ |
| 45 | for (fread(&temp_byte,1,1,input); temp_byte != '"'; fread(&temp_byte,1,1,input)) continue; |
| 46 | temp_byte = '\0'; |
| 47 | |
| 48 | while (temp_byte != '"') { |
| 49 | /* First, push three spaces to start a PUSH_IMMEDIATE command for a positive number. */ |
| 50 | uint8_t temp_output = ' '; |
| 51 | for(int i=0;i<3;i++) fwrite(&temp_output, 1, 1, output); |
| 52 | /* Second, push the ASCII character, 7 bits total, most significant bit first. */ |
| 53 | /* Remember, [Tab]=1 and [Space]=0. */ |
| 54 | uint8_t index = 7; /* 7 bits needed per ASCII character. */ |
| 55 | while (index) { |
| 56 | ((temp_byte >> (index-1)) & 1) ? (temp_output = '\t') : (temp_output = ' '); |
| 57 | fwrite(&temp_output, 1, 1, output); |
| 58 | index--; |
| 59 | } |
| 60 | /* Third, close the number with a newline. */ |
| 61 | temp_output = '\n'; |
| 62 | fwrite(&temp_output, 1, 1, output); |
| 63 | |
| 64 | /* Read the next byte to prepare for the loop test. */ |
| 65 | fseek(input, -2, SEEK_CUR); |
| 66 | fread(&temp_byte, 1, 1, input); |
| 67 | } |
| 68 | |
| 69 | /* Advance the stream pointer to the end of the string before returning. */ |
| 70 | for (fread(&temp_byte,1,1,input); temp_byte != '"'; fread(&temp_byte,1,1,input)) continue; |
| 71 | } |
| 72 | |
| 73 | int |
| 74 | main(int argc, char ** argv) |
| 75 | { |
| 76 | /* |
| 77 | * Process command line arguments |
| 78 | */ |
| 79 | int c; |
| 80 | FILE * input = NULL, * output = NULL; |
| 81 | while ((c = getopt(argc,argv,"i:o:h")) != -1) { |
| 82 | switch (c) { |
| 83 | case 'i': |
| 84 | if ((input = fopen(optarg, "r")) == NULL) { |
| 85 | fprintf(stderr, "ERROR: %s: %s\n", optarg, strerror(errno)); |
| 86 | } |
| 87 | break; |
| 88 | case 'o': |
| 89 | if ((output = fopen(optarg, "w+")) == NULL) { |
| 90 | fprintf(stderr, "ERROR: %s: %s\n", optarg, strerror(errno)); |
| 91 | } |
| 92 | break; |
| 93 | case 'h': |
| 94 | print_usage(argv); |
| 95 | exit(EXIT_SUCCESS); |
| 96 | break; |
| 97 | default: |
| 98 | break; |
| 99 | } |
| 100 | } |
| 101 | if (input == NULL) { |
| 102 | fprintf(stderr, "ERROR: Must specify a pseudo-VVhitespace source file with -i flag.\n"); |
| 103 | print_usage(argv); |
| 104 | exit(EXIT_FAILURE); |
| 105 | } |
| 106 | if (output == NULL) { |
| 107 | fprintf(stderr, "ERROR: Must specify destination for VVhitespace source file with -o flag.\n"); |
| 108 | print_usage(argv); |
| 109 | exit(EXIT_FAILURE); |
| 110 | } |
| 111 | |
| 112 | /* |
| 113 | * Main Loop |
| 114 | */ |
| 115 | uint8_t temp_byte; |
| 116 | while (fread(&temp_byte, 1, 1, input)) { |
| 117 | switch (temp_byte) { |
| 118 | case 't': |
| 119 | case 'T': |
| 120 | temp_byte = '\t'; |
| 121 | fwrite(&temp_byte, 1, 1, output); |
| 122 | break; |
| 123 | case 's': |
| 124 | case 'S': |
| 125 | temp_byte = ' '; |
| 126 | fwrite(&temp_byte, 1, 1, output); |
| 127 | break; |
| 128 | case 'n': |
| 129 | case 'N': |
| 130 | temp_byte = '\n'; |
| 131 | fwrite(&temp_byte, 1, 1, output); |
| 132 | break; |
| 133 | case 'v': |
| 134 | case 'V': |
| 135 | temp_byte = '\v'; |
| 136 | fwrite(&temp_byte, 1, 1, output); |
| 137 | break; |
| 138 | case 'a': |
| 139 | case 'A': |
| 140 | parse_ascii_string(input, output); |
| 141 | break; |
| 142 | case '\n': |
| 143 | /* Intentionally empty */ |
| 144 | break; |
| 145 | default: |
| 146 | /* The first non-[tTsSnNvVaA] character begins a comment lasting until end of line. */ |
| 147 | while (fread(&temp_byte, 1, 1, input)) { |
| 148 | if (temp_byte == '\n') break; |
| 149 | } |
| 150 | break; |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * Cleanup and exit |
| 156 | */ |
| 157 | fclose(input); |
| 158 | fclose(output); |
| 159 | |
| 160 | exit(EXIT_SUCCESS); |
| 161 | } |