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