| 1 | /*- |
| 2 | * Copyright (c) 1991 The Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * This code is derived from software contributed to Berkeley by |
| 6 | * Kenneth Almquist. |
| 7 | * |
| 8 | * %sccs.include.redist.c% |
| 9 | */ |
| 10 | |
| 11 | #ifndef lint |
| 12 | static char sccsid[] = "@(#)mystring.c 5.1 (Berkeley) %G%"; |
| 13 | #endif /* not lint */ |
| 14 | |
| 15 | /* |
| 16 | * String functions. |
| 17 | * |
| 18 | * equal(s1, s2) Return true if strings are equal. |
| 19 | * scopy(from, to) Copy a string. |
| 20 | * scopyn(from, to, n) Like scopy, but checks for overflow. |
| 21 | * strchr(s, c) Find first occurance of c in s. |
| 22 | * bcopy(from, to, n) Copy a block of memory. |
| 23 | * number(s) Convert a string of digits to an integer. |
| 24 | * is_number(s) Return true if s is a string of digits. |
| 25 | */ |
| 26 | |
| 27 | #include "shell.h" |
| 28 | #include "syntax.h" |
| 29 | #include "error.h" |
| 30 | #include "mystring.h" |
| 31 | |
| 32 | |
| 33 | char nullstr[1]; /* zero length string */ |
| 34 | |
| 35 | |
| 36 | /* |
| 37 | * scopyn - copy a string from "from" to "to", truncating the string |
| 38 | * if necessary. "To" is always nul terminated, even if |
| 39 | * truncation is performed. "Size" is the size of "to". |
| 40 | */ |
| 41 | |
| 42 | void |
| 43 | scopyn(from, to, size) |
| 44 | register char const *from; |
| 45 | register char *to; |
| 46 | register int size; |
| 47 | { |
| 48 | |
| 49 | while (--size > 0) { |
| 50 | if ((*to++ = *from++) == '\0') |
| 51 | return; |
| 52 | } |
| 53 | *to = '\0'; |
| 54 | } |
| 55 | |
| 56 | |
| 57 | /* |
| 58 | * strchr - find first occurrence of a character in a string. |
| 59 | */ |
| 60 | |
| 61 | #ifndef SYS5 |
| 62 | char * |
| 63 | mystrchr(s, charwanted) |
| 64 | char const *s; |
| 65 | register char charwanted; |
| 66 | { |
| 67 | register char const *scan; |
| 68 | |
| 69 | /* |
| 70 | * The odd placement of the two tests is so NUL is findable. |
| 71 | */ |
| 72 | for (scan = s ; *scan != charwanted ; ) /* ++ moved down for opt. */ |
| 73 | if (*scan++ == '\0') |
| 74 | return NULL; |
| 75 | return (char *)scan; |
| 76 | } |
| 77 | #endif |
| 78 | |
| 79 | |
| 80 | |
| 81 | /* |
| 82 | * bcopy - copy bytes |
| 83 | * |
| 84 | * This routine was derived from code by Henry Spencer. |
| 85 | */ |
| 86 | |
| 87 | void |
| 88 | mybcopy(src, dst, length) |
| 89 | pointer dst; |
| 90 | const pointer src; |
| 91 | register int length; |
| 92 | { |
| 93 | register char *d = dst; |
| 94 | register char *s = src; |
| 95 | |
| 96 | while (--length >= 0) |
| 97 | *d++ = *s++; |
| 98 | } |
| 99 | |
| 100 | |
| 101 | /* |
| 102 | * prefix -- see if pfx is a prefix of string. |
| 103 | */ |
| 104 | |
| 105 | int |
| 106 | prefix(pfx, string) |
| 107 | register char const *pfx; |
| 108 | register char const *string; |
| 109 | { |
| 110 | while (*pfx) { |
| 111 | if (*pfx++ != *string++) |
| 112 | return 0; |
| 113 | } |
| 114 | return 1; |
| 115 | } |
| 116 | |
| 117 | |
| 118 | /* |
| 119 | * Convert a string of digits to an integer, printing an error message on |
| 120 | * failure. |
| 121 | */ |
| 122 | |
| 123 | int |
| 124 | number(s) |
| 125 | const char *s; |
| 126 | { |
| 127 | |
| 128 | if (! is_number(s)) |
| 129 | error2("Illegal number", (char *)s); |
| 130 | return atoi(s); |
| 131 | } |
| 132 | |
| 133 | |
| 134 | |
| 135 | /* |
| 136 | * Check for a valid number. This should be elsewhere. |
| 137 | */ |
| 138 | |
| 139 | int |
| 140 | is_number(p) |
| 141 | register const char *p; |
| 142 | { |
| 143 | do { |
| 144 | if (! is_digit(*p)) |
| 145 | return 0; |
| 146 | } while (*++p != '\0'); |
| 147 | return 1; |
| 148 | } |