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utils-std

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

seq.c (2897B)

    

  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 "../lib/getopt_nolong.h"
  8. #include <ctype.h>   // isdigit
  9. #include <errno.h>   // errno
  10. #include <math.h>    // fabs
  11. #include <stdbool.h> // bool, true, false
  12. #include <stdio.h>   // fprintf
  13. #include <stdlib.h>  // exit, strtod
  14. #include <string.h>  // strerror
  15. #include <unistd.h>  // getopt, optarg, optind
  17. const char *argv0 = "seq";
  18. const char *sep = "\n";
  19. const char *term = "\n";
  21. int len = 0;
  23. bool opt_w = false;
  24. double g_last = 1.0;
  26. static void
  27. seq(double i, double step, double last)
  28. {
  29. 	printf("%0*g", len, i);
  31. 	if(i < last)
  32. 	{
  33. 		while((i + step) <= last)
  34. 			printf("%s%0*g", sep, len, i += step);
  35. 	}
  36. 	else if(i > last)
  37. 	{
  38. 		while((i - step) >= last)
  39. 			printf("%s%0*g", sep, len, i -= step);
  40. 	}
  42. 	printf("%s", term);
  44. 	if(opt_w && i != g_last)
  45. 		fprintf(stderr, "seq: error: Failed to guess last, got: %g; expected: %g\n", i, g_last);
  46. }
  48. static double
  49. get_num(char *str)
  50. {
  51. 	errno = 0;
  53. 	char *endptr = NULL;
  55. 	double num = strtod(str, &endptr);
  57. 	if(errno != 0)
  58. 	{
  59. 		fprintf(stderr, "seq: error: strtod(\"%s\"): %s\n", str, strerror(errno));
  60. 		exit(1);
  61. 	}
  63. 	if(!(endptr == NULL || endptr[0] == 0))
  64. 	{
  65. 		fprintf(stderr,
  66. 		        "seq: error: strtod(\"%s\"), invalid remaining characters found '%s'\n",
  67. 		        str,
  68. 		        endptr);
  69. 		exit(1);
  70. 	}
  72. 	return num;
  73. }
  75. static void
  76. usage(void)
  77. {
  78. 	fprintf(stderr, "usage: seq [-w] [-s separator] [first [step]] last\n");
  79. }
  81. int
  82. main(int argc, char *argv[])
  83. {
  84. 	for(int c = -1; (c = getopt_nolong(argc, argv, ":ws:t:")) != -1;)
  85. 	{
  86. 		switch(c)
  87. 		{
  88. 		case 'w':
  89. 			opt_w = true;
  90. 			break;
  91. 		case 's':
  92. 			sep = optarg;
  93. 			break;
  94. 		case 't':
  95. 			term = optarg;
  96. 			break;
  97. 		case ':':
  98. 			fprintf(stderr, "seq: error: Option -%c requires an operand\n", optopt);
  99. 			usage();
  100. 			return 1;
  101. 		case '?':
  102. 			if(!got_long_opt)
  103. 				if(isdigit(optopt))
  104. 				{
  105. 					fprintf(stderr,
  106. 					        "seq: warning: Pass -- if the first non-option argument starts with a dash(-)\n");
  107. 					optind--;
  108. 					goto getopt_end;
  109. 				}
  110. 			usage();
  111. 			return 1;
  112. 		}
  113. 	}
  114. getopt_end:
  116. 	argc -= optind;
  117. 	argv += optind;
  119. 	double first = 1.0;
  120. 	double step = 1.0;
  121. 	double last = 1.0;
  123. 	switch(argc)
  124. 	{
  125. 	case 1:
  126. 		last = get_num(argv[0]);
  127. 		break;
  128. 	case 2:
  129. 		first = get_num(argv[0]);
  130. 		last = get_num(argv[1]);
  131. 		break;
  132. 	case 3:
  133. 		first = get_num(argv[0]);
  134. 		step = fabs(get_num(argv[1]));
  135. 		last = get_num(argv[2]);
  136. 		break;
  137. 	default:
  138. 		usage();
  139. 		return 1;
  140. 	}
  142. 	if(opt_w)
  143. 	{
  144. 		double f_mod = fmod(first, step);
  145. 		double l_mod = fmod(last, step);
  147. 		g_last = last - l_mod + f_mod;
  149. 		int f_len = snprintf(NULL, 0, "%g", first);
  150. 		int l_len = snprintf(NULL, 0, "%g", g_last);
  152. 		len = f_len > l_len ? f_len : l_len;
  153. 	}
  155. 	seq(first, step, last);
  157. 	return 0;
  158. }