WebSVN – Kolibri OS – Blame – /contrib/sdk/sources/newlib/libc/stdlib/a64l.c

Rev	Author	Line No.	Line
4921	Serge	1	/*
		2	FUNCTION
		3	<>, <>---convert between radix-64 ASCII string and long
		4
		5	INDEX
		6	a64l
		7	INDEX
		8	l64a
		9
		10	ANSI_SYNOPSIS
		11	#include
		12	long a64l(const char *<[input]>);
		13	char *l64a(long <[input]>);
		14
		15	TRAD_SYNOPSIS
		16	#include
		17	long a64l(<[input]>)
		18	const char *<[input]>;
		19
		20	char *l64a(<[input]>)
		21	long <[input]>;
		22
		23	DESCRIPTION
		24	Conversion is performed between long and radix-64 characters. The
		25	<> routine transforms up to 32 bits of input value starting from
		26	least significant bits to the most significant bits. The input value
		27	is split up into a maximum of 5 groups of 6 bits and possibly one
		28	group of 2 bits (bits 31 and 30).
		29
		30	Each group of 6 bits forms a value from 0--63 which is translated into
		31	a character as follows:
		32
		33	O+
		34	o 0 = '.'
		35	o 1 = '/'
		36	o 2--11 = '0' to '9'
		37	o 12--37 = 'A' to 'Z'
		38	o 38--63 = 'a' to 'z'
		39	O-
		40
		41	When the remaining bits are zero or all bits have been translated, a
		42	null terminator is appended to the string. An input value of 0
		43	results in the empty string.
		44
		45	The <> function performs the reverse translation. Each
		46	character is used to generate a 6-bit value for up to 30 bits and then
		47	a 2-bit value to complete a 32-bit result. The null terminator means
		48	that the remaining digits are 0. An empty input string or NULL string
		49	results in 0L. An invalid string results in undefined behavior. If
		50	the size of a long is greater than 32 bits, the result is sign-extended.
		51
		52	RETURNS
		53	<> returns a null-terminated string of 0 to 6 characters.
		54	<> returns the 32-bit translated value from the input character string.
		55
		56	PORTABILITY
		57	<> and <> are non-ANSI and are defined by the Single Unix Specification.
		58
		59	Supporting OS subroutines required: None.
		60	*/
		61
		62	#include <_ansi.h>
		63	#include
		64	#include
		65
		66	long
		67	_DEFUN (a64l, (input),
		68	const char *input)
		69	{
		70	const char *ptr;
		71	char ch;
		72	int i, digit;
		73	unsigned long result = 0;
		74
		75	if (input == NULL)
		76	return 0;
		77
		78	ptr = input;
		79
		80	/* it easiest to go from most significant digit to least so find end of input or up
		81	to 6 characters worth */
		82	for (i = 0; i < 6; ++i)
		83	{
		84	if (*ptr)
		85	++ptr;
		86	}
		87
		88	while (ptr > input)
		89	{
		90	ch = *(--ptr);
		91
		92	#if defined(PREFER_SIZE_OVER_SPEED) \|\| defined(__OPTIMIZE_SIZE__)
		93	if (ch >= 'a')
		94	digit = (ch - 'a') + 38;
		95	else if (ch >= 'A')
		96	digit = (ch - 'A') + 12;
		97	else if (ch >= '0')
		98	digit = (ch - '0') + 2;
		99	else if (ch == '/')
		100	digit = 1;
		101	else
		102	digit = 0;
		103	#else /* !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) */
		104	switch (ch)
		105	{
		106	case '/':
		107	digit = 1;
		108	break;
		109	case '0':
		110	case '1':
		111	case '2':
		112	case '3':
		113	case '4':
		114	case '5':
		115	case '6':
		116	case '7':
		117	case '8':
		118	case '9':
		119	digit = (ch - '0') + 2;
		120	break;
		121	case 'A':
		122	case 'B':
		123	case 'C':
		124	case 'D':
		125	case 'E':
		126	case 'F':
		127	case 'G':
		128	case 'H':
		129	case 'I':
		130	case 'J':
		131	case 'K':
		132	case 'L':
		133	case 'M':
		134	case 'N':
		135	case 'O':
		136	case 'P':
		137	case 'Q':
		138	case 'R':
		139	case 'S':
		140	case 'T':
		141	case 'U':
		142	case 'V':
		143	case 'W':
		144	case 'X':
		145	case 'Y':
		146	case 'Z':
		147	digit = (ch - 'A') + 12;
		148	break;
		149	case 'a':
		150	case 'b':
		151	case 'c':
		152	case 'd':
		153	case 'e':
		154	case 'f':
		155	case 'g':
		156	case 'h':
		157	case 'i':
		158	case 'j':
		159	case 'k':
		160	case 'l':
		161	case 'm':
		162	case 'n':
		163	case 'o':
		164	case 'p':
		165	case 'q':
		166	case 'r':
		167	case 's':
		168	case 't':
		169	case 'u':
		170	case 'v':
		171	case 'w':
		172	case 'x':
		173	case 'y':
		174	case 'z':
		175	digit = (ch - 'a') + 38;
		176	break;
		177	default:
		178	digit = 0;
		179	break;
		180	}
		181	#endif /* !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) */
		182
		183	result = (result << 6) + digit;
		184	}
		185
		186	#if LONG_MAX > 2147483647
		187	/* for implementations where long is > 32 bits, the result must be sign-extended */
		188	if (result & 0x80000000)
		189	return (((long)-1 >> 32) << 32) + result;
		190	#endif
		191
		192	return result;
		193	}
		194

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(root)/contrib/sdk/sources/newlib/libc/stdlib/a64l.c – Rev 4921