mirror of
https://github.com/cc65/cc65.git
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395 lines
8.4 KiB
C
395 lines
8.4 KiB
C
/*
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* _scanf.c
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*
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* (C) Copyright 2001 Ullrich von Bassewitz (uz@cc65.org)
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*
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* This is the basic layer for all scanf type functions.
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*/
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#include <stdio.h>
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#include <stdarg.h>
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#include <setjmp.h>
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#include <ctype.h>
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#include <limits.h>
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#include "_scanf.h"
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/*****************************************************************************/
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/* SetJmp return codes */
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/*****************************************************************************/
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#define RC_OK 0 /* Regular call */
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#define RC_EOF 1 /* EOF reached */
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#define RC_NOCONV 2 /* No conversion possible */
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/*****************************************************************************/
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/* Data */
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/*****************************************************************************/
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static struct indesc* D; /* Copy of function argument */
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static va_list ap; /* Copy of function argument */
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static jmp_buf JumpBuf; /* Label that is used in case of EOF */
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static char C; /* Character from input */
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static unsigned Width; /* Maximum field width */
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static long IntVal; /* Converted int value */
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static unsigned Conversions; /* Number of conversions */
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/* Flags */
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static unsigned char Positive; /* Flag for positive value */
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static unsigned char NoAssign; /* Supppress assigment */
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static unsigned char IsShort; /* Short type */
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static unsigned char IsLong; /* Long type */
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/*****************************************************************************/
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/* Character sets */
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/*****************************************************************************/
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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static void ReadChar (void)
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/* Get an input character, count characters */
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{
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C = D->fin (D);
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++D->ccount;
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}
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static void SkipWhite (void)
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/* Skip white space in the input and return the first non white character */
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{
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while (isspace (C)) {
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ReadChar ();
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}
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}
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static void ReadSign (void)
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/* Read an optional sign and skip it. Store 1 in Positive if the value is
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* positive, store 0 otherwise.
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*/
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{
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switch (C) {
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case '-':
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ReadChar ();
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Positive = 0;
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case '+':
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ReadChar ();
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/* FALLTHROUGH */
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default:
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Positive = 1;
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}
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}
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static unsigned char HexVal (char C)
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/* Convert a digit to a value */
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{
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if (isdigit (C)) {
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return C - '0';
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} else {
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return C - toupper (C) + ('A' + 10);
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}
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}
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static void ReadInt (unsigned char Base)
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/* Read an integer and store it into IntVal */
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{
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/* Value must start with a digit */
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if (!isdigit (C)) {
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longjmp (JumpBuf, RC_NOCONV);
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}
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/* Read the value */
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IntVal = 0;
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while (isxdigit (C) && Width-- > 0) {
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printf ("ReadInt: '%c'\n", C);
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IntVal = IntVal * Base + HexVal (C);
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ReadChar ();
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}
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/* One more conversion */
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++Conversions;
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}
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static void AssignInt (void)
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/* Assign the integer value in Val to the next argument. The function makes
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* several non portable assumptions to reduce code size:
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* - int and unsigned types have the same representation
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* - short and int have the same representation.
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* - all pointer types have the same representation.
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*/
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{
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if (!NoAssign) {
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/* Get the next argument pointer */
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void* P = va_arg (ap, void*);
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/* Assign to the converted value */
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if (IsLong) {
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*(long*)P = IntVal;
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} else {
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*(int*)P = (int) IntVal;
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}
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}
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}
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int _scanf (struct indesc* D_, const char* format, va_list ap_)
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/* This is the routine used to do the actual work. It is called from several
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* types of wrappers to implement the actual ISO xxscanf functions.
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*/
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{
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char F; /* Character from format string */
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unsigned char Result; /* setjmp result */
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char* S;
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unsigned char Base; /* Integer base in %i */
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/* Place copies of the arguments into global variables. This is not very
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* nice, but on a 6502 platform it gives better code, since the values
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* do not have to be passed as parameters.
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*/
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D = D_;
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ap = ap_;
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/* Initialize variables */
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Conversions = 0;
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D->ccount = 0;
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/* Set up the jump label. The get() routine will use this label when EOF
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* is reached.
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*/
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Result = setjmp (JumpBuf);
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printf ("Result = %u\n", Result);
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if (Result == RC_OK) {
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Again:
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/* Get the next input character */
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ReadChar ();
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/* Walk over the format string */
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while (F = *format++) {
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/* Check for a conversion */
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if (F != '%' || *format == '%') {
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/* %% or any char other than % */
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if (F == '%') {
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++format;
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}
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/* Check for a match */
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if (isspace (F)) {
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/* Special white space handling: Any whitespace matches
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* any amount of whitespace including none(!). So this
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* match will never fail.
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*/
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SkipWhite ();
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continue;
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} else if (F != C) {
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/* A mismatch. We will stop scanning the input and return
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* the number of conversions.
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*/
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printf ("F = '%c', C = '%c' --> mismatch\n", F, C);
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return Conversions;
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} else {
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/* A match. Read the next input character and start over */
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goto Again;
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}
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} else {
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/* A conversion. Skip the percent sign. */
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F = *format++;
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/* Initialize variables */
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NoAssign = 0;
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IsShort = 0;
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IsLong = 0;
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Width = UINT_MAX;
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/* Check for flags. */
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while (1) {
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if (isdigit (F)) {
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Width = 0;
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do {
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/* ### Non portable ### */
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Width = Width * 10 + (F & 0x0F);
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F = *format++;
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} while (isdigit (F));
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} else {
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switch (F) {
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case '*': NoAssign = 1; break;
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case 'h': IsShort = 1; break;
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case 'l':
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case 'L': IsLong = 1; break;
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default: goto FlagsDone;
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}
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F = *format++;
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}
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}
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FlagsDone:
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/* Check for the actual conversion character */
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printf ("F = '%c'\n", F);
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switch (F) {
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case 'D':
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IsLong = 1;
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case 'd':
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/* Optionally signed decimal integer */
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SkipWhite ();
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ReadSign ();
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ReadInt (10);
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if (!Positive) {
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IntVal = -IntVal;
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}
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AssignInt ();
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break;
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case 'i':
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/* Optionally signed integer with a base */
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SkipWhite ();
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ReadSign ();
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if (C == '0') {
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ReadChar ();
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switch (C) {
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case 'x':
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case 'X':
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Base = 16;
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ReadChar();
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break;
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default:
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Base = 8;
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}
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} else {
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Base = 10;
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}
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ReadInt (Base);
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if (!Positive) {
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IntVal = -IntVal;
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}
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AssignInt ();
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break;
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case 'o':
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/* Unsigned octal integer */
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SkipWhite ();
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ReadInt (8);
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AssignInt ();
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break;
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case 'u':
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/* Unsigned decimal integer */
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SkipWhite ();
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ReadInt (10);
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AssignInt ();
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break;
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case 'x':
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case 'X':
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/* Unsigned hexadecimal integer */
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SkipWhite ();
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ReadInt (16);
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AssignInt ();
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break;
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case 'E':
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case 'e':
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case 'f':
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case 'g':
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/* Optionally signed float */
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break;
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case 's':
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/* Whitespace terminated string */
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SkipWhite ();
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S = NoAssign? 0 : va_arg (ap, char*);
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while (C && !isspace (C) && Width--) {
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if (S) {
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*S++ = C;
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}
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ReadChar ();
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}
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break;
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case 'c':
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/* Fixed length string */
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break;
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case '[':
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/* String using characters from a set */
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break;
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case 'p':
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/* Pointer */
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break;
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case 'n':
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/* Store characters consumed so far */
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IntVal = D->ccount;
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IsLong = 0;
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AssignInt ();
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break;
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default:
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/* Invalid conversion */
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break;
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}
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/* Skip the format char */
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goto Again;
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}
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}
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} else if (Result == RC_EOF) {
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/* Jump via JumpBuf means EOF on input */
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if (D->ccount == 0) {
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/* Special case: error */
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return -1;
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}
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}
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/* Return the number of conversions */
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return Conversions;
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}
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