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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | FUNCTION |
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| 3 | < |
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| 4 | |||
| 5 | INDEX |
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| 6 | strncpy |
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| 7 | |||
| 8 | ANSI_SYNOPSIS |
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| 9 | #include |
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| 10 | char *strncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>); |
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| 11 | |||
| 12 | TRAD_SYNOPSIS |
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| 13 | #include |
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| 14 | char *strncpy(<[dst]>, <[src]>, <[length]>) |
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| 15 | char *<[dst]>; |
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| 16 | char *<[src]>; |
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| 17 | size_t <[length]>; |
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| 18 | |||
| 19 | DESCRIPTION |
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| 20 | < |
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| 21 | the string pointed to by <[src]> (including the terminating |
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| 22 | null character) to the array pointed to by <[dst]>. If the |
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| 23 | string pointed to by <[src]> is shorter than <[length]> |
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| 24 | characters, null characters are appended to the destination |
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| 25 | array until a total of <[length]> characters have been |
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| 26 | written. |
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| 27 | |||
| 28 | RETURNS |
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| 29 | This function returns the initial value of <[dst]>. |
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| 30 | |||
| 31 | PORTABILITY |
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| 32 | < |
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| 33 | |||
| 34 | < |
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| 35 | |||
| 36 | QUICKREF |
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| 37 | strncpy ansi pure |
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| 38 | */ |
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| 39 | |||
| 40 | #include |
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| 41 | #include |
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| 42 | |||
| 43 | /*SUPPRESS 560*/ |
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| 44 | /*SUPPRESS 530*/ |
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| 45 | |||
| 46 | /* Nonzero if either X or Y is not aligned on a "long" boundary. */ |
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| 47 | #define UNALIGNED(X, Y) \ |
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| 48 | (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) |
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| 49 | |||
| 50 | #if LONG_MAX == 2147483647L |
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| 51 | #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) |
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| 52 | #else |
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| 53 | #if LONG_MAX == 9223372036854775807L |
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| 54 | /* Nonzero if X (a long int) contains a NULL byte. */ |
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| 55 | #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) |
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| 56 | #else |
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| 57 | #error long int is not a 32bit or 64bit type. |
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| 58 | #endif |
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| 59 | #endif |
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| 60 | |||
| 61 | #ifndef DETECTNULL |
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| 62 | #error long int is not a 32bit or 64bit byte |
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| 63 | #endif |
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| 64 | |||
| 65 | #define TOO_SMALL(LEN) ((LEN) < sizeof (long)) |
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| 66 | |||
| 67 | char * |
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| 68 | _DEFUN (strncpy, (dst0, src0), |
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| 69 | char *dst0 _AND |
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| 70 | _CONST char *src0 _AND |
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| 71 | size_t count) |
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| 72 | { |
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| 73 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
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| 74 | char *dscan; |
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| 75 | _CONST char *sscan; |
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| 76 | |||
| 77 | dscan = dst0; |
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| 78 | sscan = src0; |
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| 79 | while (count > 0) |
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| 80 | { |
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| 81 | --count; |
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| 82 | if ((*dscan++ = *sscan++) == '\0') |
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| 83 | break; |
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| 84 | } |
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| 85 | while (count-- > 0) |
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| 86 | *dscan++ = '\0'; |
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| 87 | |||
| 88 | return dst0; |
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| 89 | #else |
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| 90 | char *dst = dst0; |
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| 91 | _CONST char *src = src0; |
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| 92 | long *aligned_dst; |
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| 93 | _CONST long *aligned_src; |
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| 94 | |||
| 95 | /* If SRC and DEST is aligned and count large enough, then copy words. */ |
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| 96 | if (!UNALIGNED (src, dst) && !TOO_SMALL (count)) |
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| 97 | { |
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| 98 | aligned_dst = (long*)dst; |
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| 99 | aligned_src = (long*)src; |
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| 100 | |||
| 101 | /* SRC and DEST are both "long int" aligned, try to do "long int" |
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| 102 | sized copies. */ |
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| 103 | while (count >= sizeof (long int) && !DETECTNULL(*aligned_src)) |
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| 104 | { |
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| 105 | count -= sizeof (long int); |
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| 106 | *aligned_dst++ = *aligned_src++; |
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| 107 | } |
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| 108 | |||
| 109 | dst = (char*)aligned_dst; |
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| 110 | src = (char*)aligned_src; |
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| 111 | } |
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| 112 | |||
| 113 | while (count > 0) |
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| 114 | { |
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| 115 | --count; |
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| 116 | if ((*dst++ = *src++) == '\0') |
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| 117 | break; |
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| 118 | } |
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| 119 | |||
| 120 | while (count-- > 0) |
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| 121 | *dst++ = '\0'; |
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| 122 | |||
| 123 | return dst0; |
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| 124 | #endif /* not PREFER_SIZE_OVER_SPEED */ |
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| 125 | } |