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utils-std

Collection of commonly available Unix tools git clone https://anongit.hacktivis.me/git/utils-std.git/

seq.c (2798B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. #define _POSIX_C_SOURCE 200809L
  6. #include <ctype.h>   // isdigit
  7. #include <errno.h>   // errno
  8. #include <math.h>    // fabs
  9. #include <stdbool.h> // bool, true, false
  10. #include <stdio.h>   // fprintf
  11. #include <stdlib.h>  // exit, strtod
  12. #include <string.h>  // strerror
  13. #include <unistd.h>  // getopt, optarg, optind
  15. const char *sep = "\n";
  16. const char *term = "\n";
  18. int len = 0;
  20. bool opt_w = false;
  21. double g_last = 1.0;
  23. static void
  24. seq(double i, double step, double last)
  25. {
  26. 	printf("%0*g", len, i);
  28. 	if(i < last)
  29. 	{
  30. 		while((i + step) <= last)
  31. 			printf("%s%0*g", sep, len, i += step);
  32. 	}
  33. 	else if(i > last)
  34. 	{
  35. 		while((i - step) >= last)
  36. 			printf("%s%0*g", sep, len, i -= step);
  37. 	}
  39. 	printf("%s", term);
  41. 	if(opt_w && i != g_last)
  42. 		fprintf(stderr, "seq: error: Failed to guess last, got: %g; expected: %g\n", i, g_last);
  43. }
  45. static double
  46. get_num(char *str)
  47. {
  48. 	errno = 0;
  50. 	char *endptr = NULL;
  52. 	double num = strtod(str, &endptr);
  54. 	if(errno != 0)
  55. 	{
  56. 		fprintf(stderr, "seq: error: strtod(\"%s\"): %s\n", str, strerror(errno));
  57. 		exit(1);
  58. 	}
  60. 	if(!(endptr == NULL || endptr[0] == 0))
  61. 	{
  62. 		fprintf(stderr,
  63. 		        "seq: error: strtod(\"%s\"), invalid remaining characters found '%s'\n",
  64. 		        str,
  65. 		        endptr);
  66. 		exit(1);
  67. 	}
  69. 	return num;
  70. }
  72. static void
  73. usage(void)
  74. {
  75. 	fprintf(stderr, "usage: seq [-w] [-s separator] [first [step]] last\n");
  76. }
  78. int
  79. main(int argc, char *argv[])
  80. {
  81. 	int c;
  83. 	while((c = getopt(argc, argv, ":ws:t:")) != -1)
  84. 	{
  85. 		switch(c)
  86. 		{
  87. 		case 'w':
  88. 			opt_w = true;
  89. 			break;
  90. 		case 's':
  91. 			sep = optarg;
  92. 			break;
  93. 		case 't':
  94. 			term = optarg;
  95. 			break;
  96. 		case ':':
  97. 			fprintf(stderr, "seq: error: Option -%c requires an operand\n", optopt);
  98. 			usage();
  99. 			return 1;
  100. 		case '?':
  101. 			if(isdigit(optopt))
  102. 			{
  103. 				fprintf(stderr,
  104. 				        "seq: warning: Pass -- if the first non-option argument starts with a dash(-)\n");
  105. 				optind--;
  106. 				goto getopt_end;
  107. 			}
  108. 			usage();
  109. 			return 1;
  110. 		}
  111. 	}
  112. getopt_end:
  114. 	argc -= optind;
  115. 	argv += optind;
  117. 	double first = 1.0;
  118. 	double step = 1.0;
  119. 	double last = 1.0;
  121. 	switch(argc)
  122. 	{
  123. 	case 1:
  124. 		last = get_num(argv[0]);
  125. 		break;
  126. 	case 2:
  127. 		first = get_num(argv[0]);
  128. 		last = get_num(argv[1]);
  129. 		break;
  130. 	case 3:
  131. 		first = get_num(argv[0]);
  132. 		step = fabs(get_num(argv[1]));
  133. 		last = get_num(argv[2]);
  134. 		break;
  135. 	default:
  136. 		usage();
  137. 		return 1;
  138. 	}
  140. 	if(opt_w)
  141. 	{
  142. 		double f_mod = fmod(first, step);
  143. 		double l_mod = fmod(last, step);
  145. 		g_last = last - l_mod + f_mod;
  147. 		int f_len = snprintf(NULL, 0, "%g", first);
  148. 		int l_len = snprintf(NULL, 0, "%g", g_last);
  150. 		len = f_len > l_len ? f_len : l_len;
  151. 	}
  153. 	seq(first, step, last);
  155. 	return 0;
  156. }