X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2F_PDCLIB%2Fscan.c;h=6bef32ec54ceb6b56cb6a27dc4419ec5248fa870;hb=bdad1f82d0c0aa0b83e8b195303d7957c578da2e;hp=d12e8844a06e9eebc712cc68f522a5afbdc026e0;hpb=68525aefa7b7b1f2f769e287e1f2f3a4585005ff;p=pdclib

diff --git a/functions/_PDCLIB/scan.c b/functions/_PDCLIB/scan.c
index d12e884..6bef32e 100644
--- a/functions/_PDCLIB/scan.c
+++ b/functions/_PDCLIB/scan.c
@@ -7,18 +7,615 @@
 */
 
 #include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <ctype.h>
+#include <string.h>
+#include <stddef.h>
+#include <limits.h>
+
+/* Using an integer's bits as flags for both the conversion flags and length
+   modifiers.
+*/
+#define E_suppressed 1<<0
+#define E_char       1<<6
+#define E_short      1<<7
+#define E_long       1<<8
+#define E_llong      1<<9
+#define E_intmax     1<<10
+#define E_size       1<<11
+#define E_ptrdiff    1<<12
+#define E_intptr     1<<13
+#define E_ldouble    1<<14
+#define E_unsigned   1<<16
+
+
+/* Helper function to get a character from the string or stream, whatever is
+   used for input. When reading from a string, returns EOF on end-of-string
+   so that handling of the return value can be uniform for both streams and
+   strings.
+*/
+static int GET( struct _PDCLIB_status_t * status )
+{
+    int rc;
+    if ( status->stream != NULL )
+    {
+        rc = getc( status->stream );
+    }
+    else
+    {
+        rc = ( *status->s == '\0' ) ? EOF : (unsigned char)*((status->s)++);
+    }
+    if ( rc != EOF )
+    {
+        ++(status->i);
+        ++(status->current);
+    }
+    return rc;
+}
+
+
+/* Helper function to put a read character back into the string or stream,
+   whatever is used for input.
+*/
+static void UNGET( int c, struct _PDCLIB_status_t * status )
+{
+    if ( status->stream != NULL )
+    {
+        ungetc( c, status->stream ); /* TODO: Error? */
+    }
+    else
+    {
+        --(status->s);
+    }
+    --(status->i);
+    --(status->current);
+}
+
+
+/* Helper function to check if a character is part of a given scanset */
+static bool IN_SCANSET( const char * scanlist, const char * end_scanlist, int rc )
+{
+    // SOLAR
+    int previous = -1;
+    while ( scanlist != end_scanlist )
+    {
+        if ( ( *scanlist == '-' ) && ( previous != -1 ) )
+        {
+            /* possible scangroup ("a-z") */
+            if ( ++scanlist == end_scanlist )
+            {
+                /* '-' at end of scanlist does not describe a scangroup */
+                return rc == '-';
+            }
+            while ( ++previous <= (unsigned char)*scanlist )
+            {
+                if ( previous == rc )
+                {
+                    return true;
+                }
+            }
+            previous = -1;
+        }
+        else
+        {
+            /* not a scangroup, check verbatim */
+            if ( rc == (unsigned char)*scanlist )
+            {
+                return true;
+            }
+            previous = (unsigned char)(*scanlist++);
+        }
+    }
+    return false;
+}
+
 
 const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status )
 {
-    return ++spec;
+    /* generic input character */
+    int rc;
+    const char * orig_spec = spec;
+    if ( *(++spec) == '%' )
+    {
+        /* %% -> match single '%' */
+        rc = GET( status );
+        switch ( rc )
+        {
+            case EOF:
+                /* input error */
+                if ( status->n == 0 )
+                {
+                    status->n = -1;
+                }
+                return NULL;
+            case '%':
+                return ++spec;
+            default:
+                UNGET( rc, status );
+                break;
+        }
+    }
+    /* Initializing status structure */
+    status->flags = 0;
+    status->base = -1;
+    status->current = 0;
+    status->width = 0;
+    status->prec = 0;
+
+    /* '*' suppresses assigning parsed value to variable */
+    if ( *spec == '*' )
+    {
+        status->flags |= E_suppressed;
+        ++spec;
+    }
+
+    /* If a width is given, strtol() will return its value. If not given,
+       strtol() will return zero. In both cases, endptr will point to the
+       rest of the conversion specifier - just what we need.
+    */
+    char const * prev_spec = spec;
+    status->width = (int)strtol( spec, (char**)&spec, 10 );
+    if ( spec == prev_spec )
+    {
+        status->width = SIZE_MAX;
+    }
+
+    /* Optional length modifier
+       We step one character ahead in any case, and step back only if we find
+       there has been no length modifier (or step ahead another character if it
+       has been "hh" or "ll").
+    */
+    switch ( *(spec++) )
+    {
+        case 'h':
+            if ( *spec == 'h' )
+            {
+                /* hh -> char */
+                status->flags |= E_char;
+                ++spec;
+            }
+            else
+            {
+                /* h -> short */
+                status->flags |= E_short;
+            }
+            break;
+        case 'l':
+            if ( *spec == 'l' )
+            {
+                /* ll -> long long */
+                status->flags |= E_llong;
+                ++spec;
+            }
+            else
+            {
+                /* l -> long */
+                status->flags |= E_long;
+            }
+            break;
+        case 'j':
+            /* j -> intmax_t, which might or might not be long long */
+            status->flags |= E_intmax;
+            break;
+        case 'z':
+            /* z -> size_t, which might or might not be unsigned int */
+            status->flags |= E_size;
+            break;
+        case 't':
+            /* t -> ptrdiff_t, which might or might not be long */
+            status->flags |= E_ptrdiff;
+            break;
+        case 'L':
+            /* L -> long double */
+            status->flags |= E_ldouble;
+            break;
+        default:
+            --spec;
+            break;
+    }
+
+    /* Conversion specifier */
+
+    /* whether valid input had been parsed */
+    bool value_parsed = false;
+
+    switch ( *spec )
+    {
+        case 'd':
+            status->base = 10;
+            break;
+        case 'i':
+            status->base = 0;
+            break;
+        case 'o':
+            status->base = 8;
+            status->flags |= E_unsigned;
+            break;
+        case 'u':
+            status->base = 10;
+            status->flags |= E_unsigned;
+            break;
+        case 'x':
+            status->base = 16;
+            status->flags |= E_unsigned;
+            break;
+        case 'f':
+        case 'F':
+        case 'e':
+        case 'E':
+        case 'g':
+        case 'G':
+        case 'a':
+        case 'A':
+            break;
+        case 'c':
+        {
+            char * c = va_arg( status->arg, char * );
+            /* for %c, default width is one */
+            if ( status->width == SIZE_MAX )
+            {
+                status->width = 1;
+            }
+            /* reading until width reached or input exhausted */
+            while ( ( status->current < status->width ) &&
+                    ( ( rc = GET( status ) ) != EOF ) )
+            {
+                *(c++) = rc;
+                value_parsed = true;
+            }
+            /* width or input exhausted */
+            if ( value_parsed )
+            {
+                ++status->n;
+                return ++spec;
+            }
+            else
+            {
+                /* input error, no character read */
+                if ( status->n == 0 )
+                {
+                    status->n = -1;
+                }
+                return NULL;
+            }
+        }
+        case 's':
+        {
+            char * c = va_arg( status->arg, char * );
+            while ( ( status->current < status->width ) && 
+                    ( ( rc = GET( status ) ) != EOF ) )
+            {
+                if ( isspace( rc ) )
+                {
+                    UNGET( rc, status );
+                    if ( value_parsed )
+                    {
+                        /* matching sequence terminated by whitespace */
+                        *c = '\0';
+                        ++status->n;
+                        return ++spec;
+                    }
+                    else
+                    {
+                        /* matching error */
+                        return NULL;
+                    }
+                }
+                else
+                {
+                    /* match */
+                    value_parsed = true;
+                    *(c++) = rc;
+                }
+            }
+            /* width or input exhausted */
+            if ( value_parsed )
+            {
+                *c = '\0';
+                ++status->n;
+                return ++spec;
+            }
+            else
+            {
+                /* input error, no character read */
+                if ( status->n == 0 )
+                {
+                    status->n = -1;
+                }
+                return NULL;
+            }
+        }
+        case '[':
+        {
+            const char * endspec = spec;
+            bool negative_scanlist = false;
+            if ( *(++endspec) == '^' )
+            {
+                negative_scanlist = true;
+                ++endspec;
+            }
+            spec = endspec;
+            do
+            {
+                // TODO: This can run beyond a malformed format string
+                ++endspec;
+            } while ( *endspec != ']' );
+            // read according to scanlist, equiv. to %s above
+            char * c = va_arg( status->arg, char * );
+            while ( ( status->current < status->width ) && 
+                    ( ( rc = GET( status ) ) != EOF ) )
+            {
+                if ( negative_scanlist )
+                {
+                    if ( IN_SCANSET( spec, endspec, rc ) )
+                    {
+                        UNGET( rc, status );
+                        break;
+                    }
+                }
+                else
+                {
+                    if ( ! IN_SCANSET( spec, endspec, rc ) )
+                    {
+                        UNGET( rc, status );
+                        break;
+                    }
+                }
+                value_parsed = true;
+                *(c++) = rc;
+            }
+            if ( value_parsed )
+            {
+                *c = '\0';
+                ++status->n;
+                return ++endspec;
+            }
+            else
+            {
+                if ( rc == EOF )
+                {
+                    status->n = -1;
+                }
+                return NULL;
+            }
+        }
+        case 'p':
+            status->base = 16;
+            status->flags |= E_unsigned;
+            break;
+        case 'n':
+        {
+            int * val = va_arg( status->arg, int * );
+            *val = status->i;
+            return ++spec;
+        }
+        default:
+            /* No conversion specifier. Bad conversion. */
+            return orig_spec;
+    }
+
+    if ( status->base != -1 )
+    {
+        /* integer conversion */
+        uintmax_t value = 0;         /* absolute value read */
+        bool prefix_parsed = false;
+        int sign = 0;
+        while ( ( status->current < status->width ) &&
+                ( ( rc = GET( status ) ) != EOF ) )
+        {
+            if ( isspace( rc ) )
+            {
+                if ( sign )
+                {
+                    /* matching sequence terminated by whitespace */
+                    UNGET( rc, status );
+                    break;
+                }
+                else
+                {
+                    /* leading whitespace not counted against width */
+                    status->current--;
+                }
+            }
+            else if ( ! sign )
+            {
+                /* no sign parsed yet */
+                switch ( rc )
+                {
+                    case '-':
+                        sign = -1;
+                        break;
+                    case '+':
+                        sign = 1;
+                        break;
+                    default:
+                        /* not a sign; put back character */
+                        sign = 1;
+                        UNGET( rc, status );
+                        break;
+                }
+            }
+            else if ( ! prefix_parsed )
+            {
+                /* no prefix (0x... for hex, 0... for octal) parsed yet */
+                prefix_parsed = true;
+                if ( rc != '0' )
+                {
+                    /* not a prefix; if base not yet set, set to decimal */
+                    if ( status->base == 0 )
+                    {
+                        status->base = 10;
+                    }
+                    UNGET( rc, status );
+                }
+                else
+                {
+                    /* starts with zero, so it might be a prefix. */
+                    /* check what follows next (might be 0x...) */
+                    if ( ( status->current < status->width ) &&
+                         ( ( rc = GET( status ) ) != EOF ) )
+                    {
+                        if ( tolower( rc ) == 'x' )
+                        {
+                            /* 0x... would be prefix for hex base... */
+                            if ( ( status->base == 0 ) ||
+                                 ( status->base == 16 ) )
+                            {
+                                status->base = 16;
+                            }
+                            else
+                            {
+                                /* ...unless already set to other value */
+                                UNGET( rc, status );
+                                value_parsed = true;
+                            }
+                        }
+                        else
+                        {
+                            /* 0... but not 0x.... would be octal prefix */
+                            UNGET( rc, status );
+                            if ( status->base == 0 )
+                            {
+                                status->base = 8;
+                            }
+                            /* in any case we have read a zero */
+                            value_parsed = true;
+                        }
+                    }
+                    else
+                    {
+                        /* failed to read beyond the initial zero */
+                        value_parsed = true;
+                        break;
+                    }
+                }
+            }
+            else
+            {
+                char * digitptr = memchr( _PDCLIB_digits, tolower( rc ), status->base );
+                if ( digitptr == NULL )
+                {
+                    /* end of input item */
+                    UNGET( rc, status );
+                    break;
+                }
+                value *= status->base;
+                value += digitptr - _PDCLIB_digits;
+                value_parsed = true;
+            }
+        }
+        /* width or input exhausted, or non-matching character */
+        if ( ! value_parsed )
+        {
+            /* out of input before anything could be parsed - input error */
+            /* FIXME: if first character does not match, value_parsed is not set - but it is NOT an input error */
+            if ( ( status->n == 0 ) && ( rc == EOF ) )
+            {
+                status->n = -1;
+            }
+            return NULL;
+        }
+        /* convert value to target type and assign to parameter */
+        switch ( status->flags & ( E_char | E_short | E_long | E_llong |
+                                   E_intmax | E_size | E_ptrdiff |
+                                   E_unsigned ) )
+        {
+            case E_char:
+                *( va_arg( status->arg,               char * ) ) =               (char)( value * sign );
+                break;
+            case E_char | E_unsigned:
+                *( va_arg( status->arg,      unsigned char * ) ) =      (unsigned char)( value * sign );
+                break;
+
+            case E_short:
+                *( va_arg( status->arg,              short * ) ) =              (short)( value * sign );
+                break;
+            case E_short | E_unsigned:
+                *( va_arg( status->arg,     unsigned short * ) ) =     (unsigned short)( value * sign );
+                break;
+
+            case 0:
+                *( va_arg( status->arg,                int * ) ) =                (int)( value * sign );
+                break;
+            case E_unsigned:
+                *( va_arg( status->arg,       unsigned int * ) ) =       (unsigned int)( value * sign );
+                break;
+
+            case E_long:
+                *( va_arg( status->arg,               long * ) ) =               (long)( value * sign );
+                break;
+            case E_long | E_unsigned:
+                *( va_arg( status->arg,      unsigned long * ) ) =      (unsigned long)( value * sign );
+                break;
+
+            case E_llong:
+                *( va_arg( status->arg,          long long * ) ) =          (long long)( value * sign );
+                break;
+            case E_llong | E_unsigned:
+                *( va_arg( status->arg, unsigned long long * ) ) = (unsigned long long)( value * sign );
+                break;
+
+            case E_intmax:
+                *( va_arg( status->arg,           intmax_t * ) ) =           (intmax_t)( value * sign );
+                break;
+            case E_intmax | E_unsigned:
+                *( va_arg( status->arg,          uintmax_t * ) ) =          (uintmax_t)( value * sign );
+                break;
+
+            case E_size:
+                /* E_size always implies unsigned */
+                *( va_arg( status->arg,             size_t * ) ) =             (size_t)( value * sign );
+                break;
+
+            case E_ptrdiff:
+                /* E_ptrdiff always implies signed */
+                *( va_arg( status->arg,          ptrdiff_t * ) ) =          (ptrdiff_t)( value * sign );
+                break;
+
+            default:
+                puts( "UNSUPPORTED SCANF FLAG COMBINATION" );
+                return NULL; /* behaviour unspecified */
+        }
+        ++(status->n);
+        return ++spec;
+    }
+    /* TODO: Floats. */
+    return NULL;
 }
 
+
 #ifdef TEST
+#define _PDCLIB_FILEID "_PDCLIB/scan.c"
+#define _PDCLIB_STRINGIO
+
 #include <_PDCLIB_test.h>
 
+static int testscanf( char const * s, char const * format, ... )
+{
+    struct _PDCLIB_status_t status;
+    status.n = 0;
+    status.i = 0;
+    status.s = (char *)s;
+    status.stream = NULL;
+    va_start( status.arg, format );
+    if ( *(_PDCLIB_scan( format, &status )) != '\0' )
+    {
+        printf( "_PDCLIB_scan() did not return end-of-specifier on '%s'.\n", format );
+        ++TEST_RESULTS;
+    }
+    va_end( status.arg );
+    return status.n;
+}
+
+#define TEST_CONVERSION_ONLY
+
 int main( void )
 {
-    TESTCASE( NO_TESTDRIVER );
+    char source[100];
+#include "scanf_testcases.h"
     return TEST_RESULTS;
 }