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Annotation of 43BSDReno/lib/libpc/READ8.c, revision 1.1

1.1     ! root        1: /*-
        !             2:  * Copyright (c) 1979 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted
        !             6:  * provided that: (1) source distributions retain this entire copyright
        !             7:  * notice and comment, and (2) distributions including binaries display
        !             8:  * the following acknowledgement:  ``This product includes software
        !             9:  * developed by the University of California, Berkeley and its contributors''
        !            10:  * in the documentation or other materials provided with the distribution
        !            11:  * and in all advertising materials mentioning features or use of this
        !            12:  * software. Neither the name of the University nor the names of its
        !            13:  * contributors may be used to endorse or promote products derived
        !            14:  * from this software without specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #ifndef lint
        !            21: static char sccsid[] = "@(#)READ8.c    1.11 (Berkeley) 4/9/90";
        !            22: #endif /* not lint */
        !            23: 
        !            24: #include "h00vars.h"
        !            25: #include <errno.h>
        !            26: extern int errno;
        !            27: 
        !            28: double
        !            29: READ8(curfile)
        !            30:        register struct iorec   *curfile;
        !            31: {
        !            32:        double                  data;
        !            33:        int                     retval;
        !            34: 
        !            35:        if (curfile->funit & FWRITE) {
        !            36:                ERROR("%s: Attempt to read, but open for writing\n",
        !            37:                        curfile->pfname);
        !            38:        }
        !            39:        UNSYNC(curfile);
        !            40:        errno = 0;
        !            41:        retval = readreal(curfile, &data);
        !            42:        if (retval == EOF) {
        !            43:                ERROR("%s: Tried to read past end of file\n", curfile->pfname);
        !            44:        }
        !            45:        if (retval == 0) {
        !            46:                ERROR("%s: Bad data found on real read\n", curfile->pfname);
        !            47:        }
        !            48:        if (errno == ERANGE) {
        !            49:                if (data == 0.0)
        !            50:                        ERROR("%s: Underflow on real read\n", curfile->pfname);
        !            51:                else
        !            52:                        ERROR("%s: Overflow on real read\n", curfile->pfname);
        !            53:        }
        !            54:        if (errno != 0) {
        !            55:                PERROR("Error encountered on real read ", curfile->pfname);
        !            56:        }
        !            57:        return (data);
        !            58: }
        !            59: 
        !            60: /*
        !            61:  *     given a file pointer, read a sequence of characters of the
        !            62:  *     syntax of section 6.1.5 and form them into a double.
        !            63:  *
        !            64:  *     the syntax of a signed-real is:
        !            65:  *         [-|+] digit {digit} [ . digit {digit} ] [ e [+|-] digit {digit} ]
        !            66:  *
        !            67:  *     returns:
        !            68:  *             1       for success (with value in *doublep)
        !            69:  *             0       on error (with *doublep unchanged)
        !            70:  *            -1       on end-of-file during read (with *doublep unchanged)
        !            71:  *     side effects:
        !            72:  *           errno     may be set to ERANGE if atof() sets it.
        !            73:  */
        !            74: readreal(curfile, doublep)
        !            75:        struct iorec    *curfile;
        !            76:        double          *doublep;
        !            77: {
        !            78:        FILE    *filep = curfile->fbuf; /* current file variable */
        !            79:        char    *sequencep;             /* a pointer into sequence */
        !            80:        int     read;                   /* return value from fscanf() */
        !            81:        char    sequence[BUFSIZ];       /* the character sequence */
        !            82:        double  atof();
        !            83: 
        !            84: #define PUSHBACK(curfile, sequencep) \
        !            85:        if (ungetc(*--(sequencep), (curfile)->fbuf) != EOF) { \
        !            86:                *(sequencep) = '\0'; \
        !            87:        } else if ((curfile)->funit & SYNC) { \
        !            88:                (curfile)->funit &= ~SYNC; \
        !            89:                *(curfile)->fileptr = *(sequencep); \
        !            90:                *(sequencep) = '\0'; \
        !            91:        } else { \
        !            92:                return (0); \
        !            93:        }
        !            94: 
        !            95: #define        RETURN_ON_EOF(read) \
        !            96:        if (read == EOF) \
        !            97:                return (EOF); \
        !            98:        else \
        !            99:                /* void */;
        !           100: 
        !           101: #define        PUSH_TO_NULL(sequencep) \
        !           102:        while (*sequencep) \
        !           103:                sequencep++;
        !           104: 
        !           105:        /* general reader of the next character */
        !           106: #define        NEXT_CHAR(read, filep, format, sequencep) \
        !           107:        read = fscanf(filep, "%c", sequencep); \
        !           108:        RETURN_ON_EOF(read); \
        !           109:        *++sequencep = '\0';
        !           110: 
        !           111:        /* e.g. use %[0123456789] for {digit}, and check read */
        !           112: #define        SOME(read, filep, format, sequencep) \
        !           113:        read = fscanf(filep, format, sequencep); \
        !           114:        RETURN_ON_EOF(read); \
        !           115:        PUSH_TO_NULL(sequencep);
        !           116: 
        !           117:        /* e.g. use %[0123456789] for digit {digit} */
        !           118: #define        AT_LEAST_ONE(read, filep, format, sequencep) \
        !           119:        read = fscanf(filep, format, sequencep); \
        !           120:        RETURN_ON_EOF(read); \
        !           121:        if (strlen(sequencep) < 1) \
        !           122:                return (0); \
        !           123:        PUSH_TO_NULL(sequencep);
        !           124: 
        !           125: #define        ANY_ONE_OF(read, filep, format, sequencep) \
        !           126:        read = fscanf(filep, format, sequencep); \
        !           127:        RETURN_ON_EOF(read); \
        !           128:        if (strlen(sequencep) != 1) \
        !           129:                return (0); \
        !           130:        PUSH_TO_NULL(sequencep);
        !           131: 
        !           132: #define        AT_MOST_ONE(read, filep, format, sequencep) \
        !           133:        read = fscanf(filep, format, sequencep); \
        !           134:        RETURN_ON_EOF(read); \
        !           135:        if (strlen(sequencep) > 1) \
        !           136:                return (0); \
        !           137:        PUSH_TO_NULL(sequencep);
        !           138:                
        !           139:        sequencep = &sequence[0];
        !           140:        *sequencep = '\0';
        !           141:        /*
        !           142:         *      skip leading whitespace
        !           143:         */
        !           144:        SOME(read, filep, "%*[ \t\n]", sequencep);
        !           145:        /*
        !           146:         *      this much is required:
        !           147:         *      [ "+" | "-" ] digit {digits}
        !           148:         */
        !           149:        AT_MOST_ONE(read, filep, "%[+-]", sequencep);
        !           150:        AT_LEAST_ONE(read, filep, "%[0123456789]", sequencep);
        !           151:        /*
        !           152:         *      any of this is optional:
        !           153:         *      [ `.' digit {digit} ] [ `e' [ `+' | `-' ] digit {digits} ]
        !           154:         */
        !           155:        NEXT_CHAR(read, filep, "%c", sequencep);
        !           156:        switch (sequencep[-1]) {
        !           157:        default:
        !           158:                PUSHBACK(curfile, sequencep);
        !           159:                goto convert;
        !           160:        case '.':
        !           161:                SOME(read, filep, "%[0123456789]", sequencep);
        !           162:                if (!read) {
        !           163:                        PUSHBACK(curfile, sequencep);
        !           164:                        goto convert;
        !           165:                }
        !           166:                NEXT_CHAR(read, filep, "%c", sequencep);
        !           167:                if (sequencep[-1] != 'e') {
        !           168:                        PUSHBACK(curfile, sequencep);
        !           169:                        goto convert;
        !           170:                }
        !           171:                /* fall through */
        !           172:        case 'e':
        !           173:                NEXT_CHAR(read, filep, "%c", sequencep);
        !           174:                if (sequencep[-1] != '+' && sequencep[-1] != '-') {
        !           175:                        PUSHBACK(curfile, sequencep);
        !           176:                        SOME(read, filep, "%[0123456789]", sequencep);
        !           177:                        if (!read)
        !           178:                                PUSHBACK(curfile, sequencep);
        !           179:                        goto convert;
        !           180:                }
        !           181:                SOME(read, filep, "%[0123456789]", sequencep);
        !           182:                if (!read) {
        !           183:                        PUSHBACK(curfile, sequencep);
        !           184:                        PUSHBACK(curfile, sequencep);
        !           185:                }
        !           186:        }
        !           187: 
        !           188: convert:
        !           189:        /*
        !           190:         * convert sequence to double
        !           191:         */
        !           192:        *doublep = atof(&sequence[0]);
        !           193:        return (1);
        !           194: }

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