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

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