git.scottworley.com Git - overonion/blob - reverse_test.c

   1 #include "reverse_lib.h"
   2 #include "temp_file.h"
   3
   4 #include <err.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <sysexits.h>
   9 #include <unistd.h>
  10
  11 /* Reverse input_file.  Dump the result in a temporary file.  Return the temp
  12  * file's name.  The caller must free the filename. */
  13 char* reverse_to_temp_file(const char* input_file) {
  14   char* temp_filename;
  15   FILE* f;
  16   make_temporary_file(&temp_filename, &f);
  17   reverse_file(input_file, f);
  18   if (fclose(f) == EOF) err(EX_IOERR, "Couldn't close temporary file");
  19   return temp_filename;
  20 }
  21
  22 /* Compare the contents of two files.  Terminate with a diagnostic if they
  23  * differ. */
  24 void compare(const char* filename1, const char* filename2) {
  25   FILE* f1 = fopen(filename1, "r");
  26   if (f1 == NULL) err(EX_IOERR, "Couldn't open file %s", filename1);
  27   FILE* f2 = fopen(filename2, "r");
  28   if (f2 == NULL) err(EX_IOERR, "Couldn't open file %s", filename2);
  29
  30   for (int pos = 0; ; pos++) {
  31     int c1 = fgetc(f1);
  32     int c2 = fgetc(f2);
  33     if (c1 == EOF && ferror(f1)) err(EX_IOERR, "Error reading file %s", filename1);
  34     if (c2 == EOF && ferror(f2)) err(EX_IOERR, "Error reading file %s", filename2);
  35     if (c1 != c2) {
  36       errx(EX_SOFTWARE, "Unexpected difference found at offset %d after reversing twice.  "
  37                         "Expected %d but found %d", pos, c1, c2);
  38     }
  39     if (c1 == EOF) break;
  40   }
  41
  42   if (fclose(f1) != 0) err(EX_IOERR, "Couldn't close file %s", filename1);
  43   if (fclose(f2) != 0) err(EX_IOERR, "Couldn't close file %s", filename2);
  44 }
  45
  46 void test_reverse_twice_from_files_is_the_same(const char* test_filename) {
  47   char* intermediate = reverse_to_temp_file(test_filename);
  48   char* back_to_normal = reverse_to_temp_file(intermediate);
  49
  50   compare(test_filename, back_to_normal);
  51
  52   if (unlink(intermediate) == -1) err(EX_IOERR, "Couldn't remove intermediate temp file");
  53   if (unlink(back_to_normal) == -1) err(EX_IOERR, "Couldn't remove twice-reversed temp file");
  54   free(intermediate);
  55   free(back_to_normal);
  56 }
  57
  58 void test_reverse_from_file_then_from_stream_is_the_same(const char* test_filename) {
  59   int pipefd[2];
  60   if (pipe(pipefd) == -1) err(EX_OSERR, "Couldn't create pipe");
  61
  62   pid_t pid = fork();
  63   if (pid == -1) err(EX_OSERR, "Couldn't fork");
  64   if (pid == 0) {
  65     if (close(pipefd[0]) == -1) err(EX_OSERR, "Couldn't close unneeded pipe descriptor");
  66     FILE* to_second = fdopen(pipefd[1], "w");
  67     if (to_second == NULL) err(EX_IOERR, "Couldn't open pipe for writing");
  68     reverse_file(test_filename, to_second);
  69     exit(0);
  70   }
  71   if (close(pipefd[1]) == -1) err(EX_OSERR, "Couldn't close unneeded pipe descriptor");
  72   FILE* from_first = fdopen(pipefd[0], "r");
  73   if (from_first == NULL) err(EX_IOERR, "Couldn't open pipe for reading");
  74   char* out_temp_filename;
  75   FILE* out_file;
  76   make_temporary_file(&out_temp_filename, &out_file);
  77   reverse_stream(from_first, out_file);
  78   if (fclose(out_file) == EOF) err(EX_IOERR, "Couldn't close temporary file");
  79
  80   compare(test_filename, out_temp_filename);
  81
  82   if (unlink(out_temp_filename) == -1) err(EX_IOERR, "Couldn't remove temp output file");
  83   free(out_temp_filename);
  84 }
  85
  86 int main(int argc, char** argv) {
  87   char* test_filename = "reverse.c";
  88   if (argc > 2) {
  89     errx(EX_USAGE, "usage: reverse_test [datafile]");
  90   } else if (argc == 2) {
  91     test_filename = argv[1];
  92   }
  93
  94   test_reverse_twice_from_files_is_the_same(test_filename);
  95   test_reverse_from_file_then_from_stream_is_the_same(test_filename);
  96
  97   puts("PASS");
  98   return 0;
  99 }