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~/.local/bin tools and git-hooks git clone https://hacktivis.me/git/utils.git

seq.c (1886B)

    

  1. // Collection of Unix tools, comparable to coreutils
  2. // SPDX-FileCopyrightText: 2017-2022 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
  5. #define _POSIX_C_SOURCE 200809L
  6. #include <errno.h>   // errno
  7. #include <stdbool.h> // bool, true, false
  8. #include <stdio.h>   // puts, fprintf
  9. #include <stdlib.h>  // atoi, exit
  10. #include <unistd.h>  // getopt, optarg, optind
  12. char *separator = "\n";
  13. bool zero_pad   = false;
  15. void
  16. seq(long i, long step, long last)
  17. {
  18. 	if(i == last)
  19. 	{
  20. 		printf("%li%s", i, separator);
  21. 	}
  22. 	else if(i < last)
  23. 	{
  24. 		for(; i <= last; i += step)
  25. 			printf("%li%s", i, separator);
  26. 	}
  27. 	else if(i > last)
  28. 	{
  29. 		for(; i >= last; i -= step)
  30. 			printf("%li%s", i, separator);
  31. 	}
  32. }
  34. static long unsigned int
  35. safe_labs(long int a)
  36. {
  37. 	if(a >= 0)
  38. 	{
  39. 		return (long unsigned int)a;
  40. 	}
  41. 	else
  42. 	{
  43. 		return (long unsigned int)-a;
  44. 	}
  45. }
  47. long
  48. get_num(char *str)
  49. {
  50. 	errno = 0;
  52. 	long num = strtol(str, NULL, 10);
  54. 	if(errno != 0)
  55. 	{
  56. 		perror("seq: strtol:");
  57. 		exit(1);
  58. 	}
  60. 	return num;
  61. }
  63. void
  64. usage(void)
  65. {
  66. 	fprintf(stderr, "usage: seq [-w] [-s separator] [first [step]] last\n");
  67. }
  69. int
  70. main(int argc, char *argv[])
  71. {
  72. 	int c;
  74. 	/* flawfinder: ignore. Old implementations of getopt should fix themselves */
  75. 	while((c = getopt(argc, argv, ":ws:")) != -1)
  76. 	{
  77. 		switch(c)
  78. 		{
  79. 		case 'w':
  80. 			zero_pad = true;
  81. 			break;
  82. 		case 's':
  83. 			separator = optarg;
  84. 			break;
  85. 		case '?':
  86. 			usage();
  87. 			return 1;
  88. 		}
  89. 	}
  91. 	argc -= optind;
  92. 	argv += optind;
  94. 	long first = 1;
  95. 	long step  = 1;
  96. 	long last  = 1;
  98. 	switch(argc)
  99. 	{
  100. 	case 1:
  101. 		last = get_num(argv[0]);
  102. 		break;
  103. 	case 2:
  104. 		first = get_num(argv[0]);
  105. 		last  = get_num(argv[1]);
  106. 		break;
  107. 	case 3:
  108. 		first = get_num(argv[0]);
  109. 		step  = (long)safe_labs(get_num(argv[1]));
  110. 		last  = get_num(argv[2]);
  111. 		break;
  112. 	default:
  113. 		usage();
  114. 		return 1;
  115. 	}
  117. 	seq(first, step, last);
  119. 	return 0;
  120. }