355 lines
8.8 KiB
C
355 lines
8.8 KiB
C
/*
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* Copyright (c) 2012, 2014, 2016 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdio/vscanf_callback.c
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* Input format conversion.
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*/
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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enum scanmode
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{
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MODE_INIT,
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MODE_CONVSPEC,
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MODE_SCANINT,
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MODE_SCANINT_REAL,
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MODE_SCANSTRING,
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MODE_SCANSTRING_REAL,
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MODE_SCANREPORT,
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};
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enum scantype
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{
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TYPE_SHORT,
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TYPE_SHORTSHORT,
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TYPE_INT,
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TYPE_LONG,
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TYPE_LONGLONG,
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TYPE_SIZE,
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TYPE_PTRDIFF,
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TYPE_MAX,
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};
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static bool IsTypeModifier(char c)
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{
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return c == 'h' || c == 'j' || c == 'l' || c == 'L' || c == 't' || c == 'z';
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}
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static int debase(char c, int base)
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{
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if ( c == '0' )
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return 0;
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int ret = -1;
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if ( '0' <= c && c <= '9' ) { ret = c - '0' + 0; }
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if ( 'a' <= c && c <= 'f' ) { ret = c - 'a' + 10; }
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if ( 'A' <= c && c <= 'F' ) { ret = c - 'A' + 10; }
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if ( base <= ret )
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return -1;
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return ret;
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}
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int vscanf_callback(void* fp,
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int (*fgetc)(void*),
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int (*ungetc)(int, void*),
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const char* restrict format,
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va_list ap)
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{
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int matcheditems = 0;
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size_t fieldwidth = 0;
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bool escaped = false;
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bool discard = false;
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bool negint = false;
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bool intunsigned = false;
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bool leadingzero = false;
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bool hasprefix = false;
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bool string = false;
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size_t intparsed = 0;
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uintmax_t intvalue = 0;
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int ic;
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int base = 0;
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int cval;
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const size_t UNDO_MAX = 4;
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int undodata[UNDO_MAX];
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size_t undoable = 0;
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size_t strwritten = 0;
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char* strdest = NULL;
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char convc;
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int bytesparsed = 0;
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enum scantype scantype = TYPE_INT;
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enum scanmode scanmode = MODE_INIT;
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while ( true )
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{
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ic = fgetc(fp);
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if ( ic != EOF && bytesparsed != INT_MAX )
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bytesparsed++;
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unsigned char uc = ic; char c = uc;
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switch (scanmode)
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{
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case MODE_INIT:
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if ( !*format )
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{
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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goto break_loop;
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}
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if ( isspace((unsigned char) *format) )
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{
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if ( isspace(ic) )
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continue;
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else
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do format++;
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while ( isspace((unsigned char) *format) );
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}
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if ( *format == '%' && !escaped )
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{
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format++;
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scanmode = MODE_CONVSPEC;
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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continue;
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}
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escaped = false;
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if ( *format != c )
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{
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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goto break_loop;
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}
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format++;
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break;
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case MODE_CONVSPEC:
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discard = false;
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if ( *format == '*' ) { discard = true; format++; }
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fieldwidth = 0;
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while ( '0'<= *format && *format <= '9' )
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fieldwidth = fieldwidth * 10 + *format++ - '0';
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scantype = TYPE_INT;
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while ( IsTypeModifier(*format) )
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switch ( *format++ )
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{
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case 'h': scantype = scantype == TYPE_SHORT ? TYPE_SHORTSHORT
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: TYPE_SHORT; break;
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case 'j': scantype = TYPE_MAX; break;
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case 'l': scantype = scantype == TYPE_LONG ? TYPE_LONGLONG
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: TYPE_LONG; break;
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case 'L': scantype = TYPE_LONGLONG; break;
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case 't': scantype = TYPE_PTRDIFF; break;
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case 'z': scantype = TYPE_SIZE; break;
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}
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switch ( (convc = *format++) )
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{
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case '%':
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escaped = true;
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default:
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fprintf(stderr, "Warning: scanf does not support %c (%i)\n",
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convc, convc);
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fprintf(stderr, "Bailing out to prevent problems.\n");
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errno = ENOTSUP;
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return -1;
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continue;
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case 'd':
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base = 10; scanmode = MODE_SCANINT; intunsigned = false; break;
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case 'i':
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base = 0; scanmode = MODE_SCANINT; intunsigned = false; break;
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case 'o':
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base = 0; scanmode = MODE_SCANINT; intunsigned = true; break;
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case 'u':
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base = 10; scanmode = MODE_SCANINT; intunsigned = true; break;
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case 'x':
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case 'X':
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base = 16; scanmode = MODE_SCANINT; intunsigned = true; break;
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case 'c':
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string = false; scanmode = MODE_SCANSTRING; break;
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case 's':
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string = true; scanmode = MODE_SCANSTRING; break;
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case 'n':
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scanmode = MODE_SCANREPORT; break;
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}
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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continue;
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case MODE_SCANINT:
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intparsed = 0;
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intvalue = 0;
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leadingzero = false;
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negint = false;
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hasprefix = false;
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undoable = 0;
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scanmode = MODE_SCANINT_REAL;
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case MODE_SCANINT_REAL:
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if ( fieldwidth )
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{
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fprintf(stderr, "Error: field width not supported for integers in scanf.\n");
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errno = ENOTSUP;
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return -1;
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}
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if ( !undoable && isspace(ic) )
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continue;
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if ( undoable < UNDO_MAX )
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undodata[undoable++] = ic;
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if ( !intparsed && c == '-' && !intunsigned && !negint )
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{
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negint = true;
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continue;
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}
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if ( !intparsed && c == '0' && !hasprefix &&
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(!base || base == 8 || base == 16) && !leadingzero )
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leadingzero = true;
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if ( intparsed == 1 && (c == 'x' || c == 'X') && !hasprefix &&
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(!base || base == 16) && leadingzero )
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{
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base = 16;
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leadingzero = false;
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hasprefix = true;
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intparsed = 0;
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continue;
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}
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else if ( intparsed == 1 && '1' <= c && c <= '7' && !hasprefix &&
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(!base || base == 8) && leadingzero )
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{
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base = 8;
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hasprefix = true;
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leadingzero = false;
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}
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else if ( !intparsed && '0' <= c && c <= '9' && !hasprefix &&
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(!base || base == 10) && !leadingzero )
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{
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base = 10;
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leadingzero = false;
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hasprefix = true;
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}
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cval = debase(c, base);
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if ( cval < 0 )
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{
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if ( !intparsed )
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{
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while ( undoable )
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{
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ungetc(undodata[--undoable], fp);
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bytesparsed--;
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}
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goto break_loop;
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}
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scanmode = MODE_INIT;
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undoable = 0;
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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if ( discard ) { discard = false; continue; }
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uintmax_t uintmaxval = intvalue;
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// TODO: Possible truncation of INTMAX_MIN!
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intmax_t intmaxval = uintmaxval;
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if ( negint ) intmaxval = -intmaxval;
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bool un = intunsigned;
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switch ( scantype )
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{
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case TYPE_SHORTSHORT:
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if ( un ) *va_arg(ap, unsigned char*) = uintmaxval;
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else *va_arg(ap, signed char*) = intmaxval;
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break;
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case TYPE_SHORT:
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if ( un ) *va_arg(ap, unsigned short*) = uintmaxval;
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else *va_arg(ap, signed short*) = intmaxval;
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break;
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case TYPE_INT:
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if ( un ) *va_arg(ap, unsigned int*) = uintmaxval;
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else *va_arg(ap, signed int*) = intmaxval;
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break;
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case TYPE_LONG:
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if ( un ) *va_arg(ap, unsigned long*) = uintmaxval;
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else *va_arg(ap, signed long*) = intmaxval;
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break;
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case TYPE_LONGLONG:
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if ( un ) *va_arg(ap, unsigned long long*) = uintmaxval;
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else *va_arg(ap, signed long long*) = intmaxval;
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break;
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case TYPE_PTRDIFF:
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*va_arg(ap, ptrdiff_t*) = intmaxval;
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break;
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case TYPE_SIZE:
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if ( un ) *va_arg(ap, size_t*) = uintmaxval;
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else *va_arg(ap, ssize_t*) = intmaxval;
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break;
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case TYPE_MAX:
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if ( un ) *va_arg(ap, uintmax_t*) = uintmaxval;
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else *va_arg(ap, intmax_t*) = intmaxval;
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break;
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}
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matcheditems++;
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continue;
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}
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intvalue = intvalue * (uintmax_t) base + (uintmax_t) cval;
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intparsed++;
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continue;
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case MODE_SCANSTRING:
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if ( !fieldwidth )
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fieldwidth = string ? SIZE_MAX : 1;
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scanmode = MODE_SCANSTRING_REAL;
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strwritten = 0;
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strdest = discard ? NULL : va_arg(ap, char*);
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case MODE_SCANSTRING_REAL:
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if ( string && !strwritten && isspace(ic) )
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continue;
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if ( string && strwritten &&
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(ic == EOF || isspace(ic) || strwritten == fieldwidth) )
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{
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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if ( !discard )
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strdest[strwritten] = '\0';
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matcheditems++;
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scanmode = MODE_INIT;
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continue;
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}
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if ( !string && strwritten == fieldwidth )
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{
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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scanmode = MODE_INIT;
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continue;
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}
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if ( ic == EOF )
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goto break_loop;
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if ( !discard )
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strdest[strwritten++] = c;
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continue;
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case MODE_SCANREPORT:
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ungetc(ic, fp);
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if ( ic != EOF )
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bytesparsed--;
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if ( !discard )
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*va_arg(ap, int*) = bytesparsed;
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scanmode = MODE_INIT;
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continue;
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}
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}
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break_loop:
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return matcheditems;
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}
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