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Annotation of researchv10dc/cmd/worm/scsi/tcl/strtoul.c, revision 1.1

1.1     ! root        1: /* 
        !             2:  * strtoul.c --
        !             3:  *
        !             4:  *     Source code for the "strtoul" library procedure.
        !             5:  *
        !             6:  * Copyright 1988 Regents of the University of California
        !             7:  * Permission to use, copy, modify, and distribute this
        !             8:  * software and its documentation for any purpose and without
        !             9:  * fee is hereby granted, provided that the above copyright
        !            10:  * notice appear in all copies.  The University of California
        !            11:  * makes no representations about the suitability of this
        !            12:  * software for any purpose.  It is provided "as is" without
        !            13:  * express or implied warranty.
        !            14:  */
        !            15: 
        !            16: #ifndef lint
        !            17: static char rcsid[] = "$Header: /sprite/src/lib/c/stdlib/RCS/strtoul.c,v 1.2 89/03/22 00:47:33 rab Exp $ SPRITE (Berkeley)";
        !            18: #endif /* not lint */
        !            19: 
        !            20: #include <sprite.h>
        !            21: #include <stdlib.h>
        !            22: #include <ctype.h>
        !            23: 
        !            24: /*
        !            25:  * The table below is used to convert from ASCII digits to a
        !            26:  * numerical equivalent.  It maps from '0' through 'z' to integers
        !            27:  * (100 for non-digit characters).
        !            28:  */
        !            29: 
        !            30: static char cvtIn[] = {
        !            31:     0, 1, 2, 3, 4, 5, 6, 7, 8, 9,              /* '0' - '9' */
        !            32:     100, 100, 100, 100, 100, 100, 100,         /* punctuation */
        !            33:     10, 11, 12, 13, 14, 15, 16, 17, 18, 19,    /* 'A' - 'Z' */
        !            34:     20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
        !            35:     30, 31, 32, 33, 34, 35,
        !            36:     100, 100, 100, 100, 100, 100,              /* punctuation */
        !            37:     10, 11, 12, 13, 14, 15, 16, 17, 18, 19,    /* 'a' - 'z' */
        !            38:     20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
        !            39:     30, 31, 32, 33, 34, 35};
        !            40: 
        !            41: /*
        !            42:  *----------------------------------------------------------------------
        !            43:  *
        !            44:  * strtoul --
        !            45:  *
        !            46:  *     Convert an ASCII string into an integer.
        !            47:  *
        !            48:  * Results:
        !            49:  *     The return value is the integer equivalent of string.  If endPtr
        !            50:  *     is non-NULL, then *endPtr is filled in with the character
        !            51:  *     after the last one that was part of the integer.  If string
        !            52:  *     doesn't contain a valid integer value, then zero is returned
        !            53:  *     and *endPtr is set to string.
        !            54:  *
        !            55:  * Side effects:
        !            56:  *     None.
        !            57:  *
        !            58:  *----------------------------------------------------------------------
        !            59:  */
        !            60: 
        !            61: unsigned long int
        !            62: strtoul(string, endPtr, base)
        !            63:     char *string;              /* String of ASCII digits, possibly
        !            64:                                 * preceded by white space.  For bases
        !            65:                                 * greater than 10, either lower- or
        !            66:                                 * upper-case digits may be used.
        !            67:                                 */
        !            68:     char **endPtr;             /* Where to store address of terminating
        !            69:                                 * character, or NULL. */
        !            70:     int base;                  /* Base for conversion.  Must be less
        !            71:                                 * than 37.  If 0, then the base is chosen
        !            72:                                 * from the leading characters of string:
        !            73:                                 * "0x" means hex, "0" means octal, anything
        !            74:                                 * else means decimal.
        !            75:                                 */
        !            76: {
        !            77:     register char *p;
        !            78:     register unsigned long int result = 0;
        !            79:     register unsigned digit;
        !            80:     int anyDigits = FALSE;
        !            81: 
        !            82:     /*
        !            83:      * Skip any leading blanks.
        !            84:      */
        !            85: 
        !            86:     p = string;
        !            87:     while (isspace(*p)) {
        !            88:        p += 1;
        !            89:     }
        !            90: 
        !            91:     /*
        !            92:      * If no base was provided, pick one from the leading characters
        !            93:      * of the string.
        !            94:      */
        !            95:     
        !            96:     if (base == 0)
        !            97:     {
        !            98:        if (*p == '0') {
        !            99:            p += 1;
        !           100:            if (*p == 'x') {
        !           101:                p += 1;
        !           102:                base = 16;
        !           103:            } else {
        !           104: 
        !           105:                /*
        !           106:                 * Must set anyDigits here, otherwise "0" produces a
        !           107:                 * "no digits" error.
        !           108:                 */
        !           109: 
        !           110:                anyDigits = TRUE;
        !           111:                base = 8;
        !           112:            }
        !           113:        }
        !           114:        else base = 10;
        !           115:     } else if (base == 16) {
        !           116: 
        !           117:        /*
        !           118:         * Skip a leading "0x" from hex numbers.
        !           119:         */
        !           120: 
        !           121:        if ((p[0] == '0') && (p[1] == 'x')) {
        !           122:            p += 2;
        !           123:        }
        !           124:     }
        !           125: 
        !           126:     /*
        !           127:      * Sorry this code is so messy, but speed seems important.  Do
        !           128:      * different things for base 8, 10, 16, and other.
        !           129:      */
        !           130: 
        !           131:     if (base == 8) {
        !           132:        for ( ; ; p += 1) {
        !           133:            digit = *p - '0';
        !           134:            if (digit > 7) {
        !           135:                break;
        !           136:            }
        !           137:            result = (result << 3) + digit;
        !           138:            anyDigits = TRUE;
        !           139:        }
        !           140:     } else if (base == 10) {
        !           141:        for ( ; ; p += 1) {
        !           142:            digit = *p - '0';
        !           143:            if (digit > 9) {
        !           144:                break;
        !           145:            }
        !           146:            result = (10*result) + digit;
        !           147:            anyDigits = TRUE;
        !           148:        }
        !           149:     } else if (base == 16) {
        !           150:        for ( ; ; p += 1) {
        !           151:            digit = *p - '0';
        !           152:            if (digit > ('z' - '0')) {
        !           153:                break;
        !           154:            }
        !           155:            digit = cvtIn[digit];
        !           156:            if (digit > 15) {
        !           157:                break;
        !           158:            }
        !           159:            result = (result << 4) + digit;
        !           160:            anyDigits = TRUE;
        !           161:        }
        !           162:     } else {
        !           163:        for ( ; ; p += 1) {
        !           164:            digit = *p - '0';
        !           165:            if (digit > ('z' - '0')) {
        !           166:                break;
        !           167:            }
        !           168:            digit = cvtIn[digit];
        !           169:            if (digit >= base) {
        !           170:                break;
        !           171:            }
        !           172:            result = result*base + digit;
        !           173:            anyDigits = TRUE;
        !           174:        }
        !           175:     }
        !           176: 
        !           177:     /*
        !           178:      * See if there were any digits at all.
        !           179:      */
        !           180: 
        !           181:     if (!anyDigits) {
        !           182:        p = string;
        !           183:     }
        !           184: 
        !           185:     if (endPtr != NULL) {
        !           186:        *endPtr = p;
        !           187:     }
        !           188: 
        !           189:     return result;
        !           190: }

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