Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com X-Originating-IP: [203.152.128.2] X-Originating-Email: [vm6580 AT hotmail DOT com] From: "Vikram Mehta" To: elfyn AT cygwin DOT com Cc: CYGWIN AT cygwin DOT com Subject: Here is code for dirname basename and getline Date: Sat, 28 Jun 2003 13:36:17 +0530 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 28 Jun 2003 08:06:17.0522 (UTC) FILETIME=[26DB4920:01C33D4C] Hi Elfyn, Thanx again, Anyways I have added code for thse three functions incase somebody needs them This code is not mine but i thought, incase soembody needs it, he will have to spent less time on this issue /*Code starts here*/ ssize_t getdelim(char **linebuf, size_t *linebufsz, int delimiter, FILE *file) { static const int GROWBY = 80; /* how large we will grow strings by */ int ch; int idx = 0; if ((file == NULL || linebuf==NULL || *linebuf == NULL || *linebufsz == 0) && !(*linebuf == NULL && *linebufsz ==0 )) { errno=EINVAL; return -1; } if (*linebuf == NULL && *linebufsz == 0){ *linebuf = malloc(GROWBY); if (!*linebuf) { errno=ENOMEM; return -1; } *linebufsz += GROWBY; } while (1) { ch = fgetc(file); if (ch == EOF) break; /* grow the line buffer as necessary */ while (idx > *linebufsz-2) { *linebuf = realloc(*linebuf, *linebufsz += GROWBY); if (!*linebuf) { errno=ENOMEM; return -1; } } (*linebuf)[idx++] = (char)ch; if ((char)ch == delimiter) break; } if (idx != 0) (*linebuf)[idx] = 0; else if ( ch == EOF ) return -1; return idx; } ssize_t getline(char **linebuf, size_t *n, FILE *file) { return (getdelim (linebuf, n, '\n', file)); } char * basename (filename) const char *filename; { char *p = strrchr (filename, '/'); return p ? p + 1 : (char *) filename; } # define __ptr_t void * __ptr_t __memrchr (s, c_in, n) const __ptr_t s; int c_in; size_t n; { const unsigned char *char_ptr; const unsigned long int *longword_ptr; unsigned long int longword, magic_bits, charmask; unsigned char c; c = (unsigned char) c_in; /* Handle the last few characters by reading one character at a time. Do this until CHAR_PTR is aligned on a longword boundary. */ for (char_ptr = (const unsigned char *) s + n; n > 0 && ((unsigned long int) char_ptr & (sizeof (longword) - 1)) != 0; --n) if (*--char_ptr == c) return (__ptr_t) char_ptr; /* All these elucidatory comments refer to 4-byte longwords, but the theory applies equally well to 8-byte longwords. */ longword_ptr = (const unsigned long int *) char_ptr; /* Bits 31, 24, 16, and 8 of this number are zero. Call these bits the "holes." Note that there is a hole just to the left of each byte, with an extra at the end: bits: 01111110 11111110 11111110 11111111 bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD The 1-bits make sure that carries propagate to the next 0-bit. The 0-bits provide holes for carries to fall into. */ if (sizeof (longword) != 4 && sizeof (longword) != 8) abort (); #if LONG_MAX <= LONG_MAX_32_BITS magic_bits = 0x7efefeff; #else magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff; #endif /* Set up a longword, each of whose bytes is C. */ charmask = c | (c << 8); charmask |= charmask << 16; #if LONG_MAX > LONG_MAX_32_BITS charmask |= charmask << 32; #endif /* Instead of the traditional loop which tests each character, we will test a longword at a time. The tricky part is testing if *any of the four* bytes in the longword in question are zero. */ while (n >= sizeof (longword)) { /* We tentatively exit the loop if adding MAGIC_BITS to LONGWORD fails to change any of the hole bits of LONGWORD. 1) Is this safe? Will it catch all the zero bytes? Suppose there is a byte with all zeros. Any carry bits propagating from its left will fall into the hole at its least significant bit and stop. Since there will be no carry from its most significant bit, the LSB of the byte to the left will be unchanged, and the zero will be detected. 2) Is this worthwhile? Will it ignore everything except zero bytes? Suppose every byte of LONGWORD has a bit set somewhere. There will be a carry into bit 8. If bit 8 is set, this will carry into bit 16. If bit 8 is clear, one of bits 9-15 must be set, so there will be a carry into bit 16. Similarly, there will be a carry into bit 24. If one of bits 24-30 is set, there will be a carry into bit 31, so all of the hole bits will be changed. The one misfire occurs when bits 24-30 are clear and bit 31 is set; in this case, the hole at bit 31 is not changed. If we had access to the processor carry flag, we could close this loophole by putting the fourth hole at bit 32! So it ignores everything except 128's, when they're aligned properly. 3) But wait! Aren't we looking for C, not zero? Good point. So what we do is XOR LONGWORD with a longword, each of whose bytes is C. This turns each byte that is C into a zero. */ longword = *--longword_ptr ^ charmask; /* Add MAGIC_BITS to LONGWORD. */ if ((((longword + magic_bits) /* Set those bits that were unchanged by the addition. */ ^ ~longword) /* Look at only the hole bits. If any of the hole bits are unchanged, most likely one of the bytes was a zero. */ & ~magic_bits) != 0) { /* Which of the bytes was C? If none of them were, it was a misfire; continue the search. */ const unsigned char *cp = (const unsigned char *) longword_ptr; #if LONG_MAX > 2147483647 if (cp[7] == c) return (__ptr_t) &cp[7]; if (cp[6] == c) return (__ptr_t) &cp[6]; if (cp[5] == c) return (__ptr_t) &cp[5]; if (cp[4] == c) return (__ptr_t) &cp[4]; #endif if (cp[3] == c) return (__ptr_t) &cp[3]; if (cp[2] == c) return (__ptr_t) &cp[2]; if (cp[1] == c) return (__ptr_t) &cp[1]; if (cp[0] == c) return (__ptr_t) cp; } n -= sizeof (longword); } char_ptr = (const unsigned char *) longword_ptr; while (n-- > 0) { if (*--char_ptr == c) return (__ptr_t) char_ptr; } return 0; } char * dirname (char *path) { static const char dot[] = "."; char *last_slash; /* Find last '/'. */ last_slash = path != NULL ? strrchr (path, '/') : NULL; if (last_slash != NULL && last_slash != path && last_slash[1] == '\0') { /* Determine whether all remaining characters are slashes. */ char *runp; for (runp = last_slash; runp != path; --runp) if (runp[-1] != '/') break; /* The '/' is the last character, we have to look further. */ if (runp != path) last_slash = __memrchr (path, '/', runp - path); } if (last_slash != NULL) { /* Determine whether all remaining characters are slashes. */ char *runp; for (runp = last_slash; runp != path; --runp) if (runp[-1] != '/') break; /* Terminate the path. */ if (runp == path) { /* The last slash is the first character in the string. We have to return "/". As a special case we have to return "//" if there are exactly two slashes at the beginning of the string. See XBD 4.10 Path Name Resolution for more information. */ if (last_slash == path + 1) ++last_slash; else last_slash = path + 1; } last_slash[0] = '\0'; } else /* This assignment is ill-designed but the XPG specs require to return a string containing "." in any case no directory part is found and so a static and constant string is required. */ path = (char *) dot; return path; } /* Code Ends*/ _________________________________________________________________ Are you Unmarried? Register in India's No 1 Matrimony. http://www.bharatmatrimony.com/cgi-bin/bmclicks1.cgi?4d -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/