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687 lines
18 KiB
C
687 lines
18 KiB
C
/*
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* _scanf.c
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*
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* (C) Copyright 2001-2002 Ullrich von Bassewitz (uz@cc65.org)
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*
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* This is the basic layer for all scanf type functions. It should get
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* rewritten in assembler at some time in the future, so most of the code
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* is not as elegant as it could be.
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*/
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#include <stdio.h>
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#include <stdarg.h>
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#include <stddef.h>
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#include <string.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 scanfdata* 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 unsigned CharCount; /* Characters read so far */
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static int 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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static unsigned char IntBytes; /* Number of bytes-1 for int 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 Invert; /* Do we need to invert the charset? */
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static unsigned char CharSet[32]; /* 32 * 8 bits = 256 bits */
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static const unsigned char Bits[8] = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80
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};
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/* We need C to be 16 bits since we cannot check for EOF otherwise.
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* Unfortunately, this causes the code to be quite larger, even if for most
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* purposes, checking the low byte would be enough, since if C is EOF, the
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* low byte will not match any useful character anyway (at least for the
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* supported platforms - I know that this is not portable). So the following
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* macro is used to access just the low byte of C.
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*/
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#define CHAR(c) (*((unsigned char*)&(c)))
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/*****************************************************************************/
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/* Character sets */
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/*****************************************************************************/
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static void __fastcall__ AddCharToSet (unsigned char C)
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/* Set the given bit in the character set */
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{
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asm ("ldy #%o", C);
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asm ("lda (sp),y");
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asm ("lsr a");
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asm ("lsr a");
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asm ("lsr a");
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asm ("tax");
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asm ("lda (sp),y");
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asm ("and #$07");
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asm ("tay");
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asm ("lda %v,y", Bits);
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asm ("ora %v,x", CharSet);
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asm ("sta %v,x", CharSet);
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}
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static unsigned char __fastcall__ IsCharInSet (unsigned char C)
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/* Check if the given char is part of the character set */
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{
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asm ("ldy #%o", C);
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asm ("lda (sp),y");
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asm ("lsr a");
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asm ("lsr a");
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asm ("lsr a");
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asm ("tax");
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asm ("lda (sp),y");
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asm ("and #$07");
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asm ("tay");
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asm ("lda %v,y", Bits);
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asm ("and %v,x", CharSet);
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asm ("ldx #$00");
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return __AX__;
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}
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static void InvertCharSet (void)
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/* Invert the character set */
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{
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asm ("ldy #%b", sizeof (CharSet) - 1);
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asm ("L1:");
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asm ("lda %v,y", CharSet);
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asm ("eor #$FF");
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asm ("sta %v,y", CharSet);
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asm ("dey");
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asm ("bpl L1");
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}
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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static void __fastcall__ Error (unsigned char Code)
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/* Does a longjmp using the given code */
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{
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longjmp (JumpBuf, 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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/* Move D to ptr1 */
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asm ("lda %v", D_);
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asm ("ldx %v+1", D_);
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asm ("sta ptr1");
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asm ("stx ptr1+1");
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/* Copy the get vector to jmpvec */
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asm ("ldy #%b", offsetof (struct scanfdata, get));
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asm ("lda (ptr1),y");
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asm ("sta jmpvec+1");
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asm ("iny");
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asm ("lda (ptr1),y");
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asm ("sta jmpvec+2");
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/* Load D->data into __AX__ */
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asm ("ldy #%b", offsetof (struct scanfdata, data)+1);
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asm ("lda (ptr1),y");
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asm ("tax");
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asm ("dey");
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asm ("lda (ptr1),y");
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/* Call the get routine */
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asm ("jsr jmpvec");
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/* Assign the result to C */
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asm ("sta %v", C);
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asm ("stx %v+1", C);
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/* If C is not EOF, bump the character counter. */
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asm ("inx");
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asm ("bne %g", Done);
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asm ("cmp #$FF");
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asm ("bne %g", Done);
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/* Must bump CharCount. */
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asm ("inc %v", CharCount);
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asm ("bne %g", Done);
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asm ("inc %v+1", CharCount);
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Done:
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}
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static void ReadCharWithCheck (void)
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/* Get an input char, use longjmp in case of EOF */
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{
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ReadChar ();
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if (C == EOF) {
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Error (RC_EOF);
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}
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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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/* We can ignore the high byte of C here, since if it is EOF, the lower
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* byte won't match anyway.
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*/
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asm ("lda %v", C);
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asm ("cmp #'-'");
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asm ("bne %g", NotNeg);
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/* Negative value */
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asm ("jsr %v", ReadChar);
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asm ("lda #$00"); /* Flag as negative */
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asm ("beq %g", Store);
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/* Positive value */
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NotNeg:
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asm ("cmp #'+'");
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asm ("bne %g", Pos);
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asm ("jsr %v", ReadChar); /* Skip the + sign */
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Pos:
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asm ("lda #$01"); /* Flag as positive */
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Store:
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asm ("sta %v", Positive);
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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 toupper (C) - ('A' - 10);
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}
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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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__AX__ = (unsigned) va_arg (ap, void*);
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/* Store the argument pointer into ptr1 */
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asm ("sta ptr1");
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asm ("stx ptr1+1");
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/* Get the number of bytes-1 to copy */
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asm ("ldy %v", IntBytes);
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/* Assign the integer value */
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Loop: asm ("lda %v,y", IntVal);
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asm ("sta (ptr1),y");
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asm ("dey");
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asm ("bpl %g", Loop);
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}
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}
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static unsigned char ReadInt (unsigned char Base)
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/* Read an integer and store it into IntVal. Returns the number of chars
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* converted. Does NOT bump Conversions.
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*/
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{
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unsigned char Val;
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unsigned char CharCount = 0;
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/* Read the integer value */
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IntVal = 0;
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while (isxdigit (C) && Width-- > 0 && (Val = HexVal (C)) < Base) {
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++CharCount;
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IntVal = IntVal * Base + Val;
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ReadChar ();
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}
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/* If we didn't convert anything, it's an error */
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if (CharCount == 0) {
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Error (RC_NOCONV);
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}
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/* Return the number of characters converted */
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return CharCount;
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}
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static void __fastcall__ ScanInt (unsigned char Base)
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/* Scan an integer including white space, sign and optional base spec,
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* and store it into IntVal.
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*/
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{
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/* Skip whitespace */
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SkipWhite ();
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/* Read an optional sign */
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ReadSign ();
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/* If Base is unknown (zero), figure it out */
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if (Base == 0) {
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if (CHAR (C) == '0') {
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ReadChar ();
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switch (CHAR (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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}
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/* Read the integer value */
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ReadInt (Base);
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/* Apply the sign */
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if (!Positive) {
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IntVal = -IntVal;
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}
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/* Assign the value to the next argument unless suppressed */
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AssignInt ();
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/* One more conversion */
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++Conversions;
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}
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int __fastcall__ _scanf (register struct scanfdata* D,
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register 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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register 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 HaveWidth; /* True if a width was given */
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char Start; /* Start of range */
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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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CharCount = 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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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 in the
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* format string matches any amount of whitespace including
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* none(!). So this 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 match. Read the next input character and start over */
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goto Again;
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} else {
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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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return Conversions;
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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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/* 1. Assignment suppression */
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if (F == '*') {
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F = *format++;
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NoAssign = 1;
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} else {
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NoAssign = 0;
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}
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/* 2. Maximum field width */
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Width = UINT_MAX;
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HaveWidth = 0;
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if (isdigit (F)) {
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HaveWidth = 1;
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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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}
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/* 3. Length modifier */
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IntBytes = sizeof(int) - 1;
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switch (F) {
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case 'h':
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if (*format == 'h') {
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IntBytes = sizeof(char) - 1;
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++format;
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}
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F = *format++;
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break;
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case 'l':
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if (*format == 'l') {
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/* Treat long long as long */
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++format;
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}
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/* FALLTHROUGH */
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case 'j': /* intmax_t */
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IntBytes = sizeof(long) - 1;
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F = *format++;
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break;
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case 'z': /* size_t */
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case 't': /* ptrdiff_t */
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case 'L': /* long double - ignore this one */
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F = *format++;
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break;
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}
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/* 4. Conversion specifier */
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switch (F) {
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/* 'd' and 'u' conversions are actually the same, since the
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* standard says that evene the 'u' modifier allows an
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* optionally signed integer.
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*/
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case 'd': /* Optionally signed decimal integer */
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case 'u':
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ScanInt (10);
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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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ScanInt (0);
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break;
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case 'o':
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/* Optionally signed octal integer */
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ScanInt (8);
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break;
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case 'x':
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case 'X':
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/* Optionally signed hexadecimal integer */
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ScanInt (16);
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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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Error (RC_NOCONV);
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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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if (!NoAssign) {
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S = va_arg (ap, char*);
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}
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while (!isspace (C) && Width--) {
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if (!NoAssign) {
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*S++ = C;
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}
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ReadChar ();
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}
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/* Terminate the string just read */
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if (!NoAssign) {
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*S = '\0';
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}
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++Conversions;
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break;
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case 'c':
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/* Fixed length string, NOT zero terminated */
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if (!HaveWidth) {
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/* No width given, default is 1 */
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Width = 1;
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}
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if (!NoAssign) {
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S = va_arg (ap, char*);
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while (Width--) {
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*S++ = C;
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ReadCharWithCheck ();
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}
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} else {
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/* Just skip as many chars as given */
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while (Width--) {
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ReadCharWithCheck ();
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}
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}
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++Conversions;
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break;
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case '[':
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/* String using characters from a set */
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Invert = 0;
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/* Clear the set */
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memset (CharSet, 0, sizeof (CharSet));
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F = *format++;
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if (F == '^') {
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Invert = 1;
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F = *format++;
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}
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if (F == ']') {
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AddCharToSet (']');
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F = *format++;
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}
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/* Read the characters that are part of the set */
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while (F != ']' && F != '\0') {
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if (*format == '-') {
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/* A range. Get start and end, skip the '-' */
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Start = F;
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F = *++format;
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++format;
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if (F == ']') {
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/* '-' as last char means: include '-' */
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AddCharToSet (Start);
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AddCharToSet ('-');
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} else if (F != '\0') {
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/* Include all chars in the range */
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while (1) {
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AddCharToSet (Start);
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if (Start == F) {
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break;
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}
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++Start;
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}
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/* Get next char after range */
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F = *format++;
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}
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} else {
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/* Just a character */
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AddCharToSet (F);
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/* Get next char */
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F = *format++;
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}
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}
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/* Invert the set if requested */
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if (Invert) {
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InvertCharSet ();
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}
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/* We have the set in CharSet. Read characters and
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* store them into a string while they are part of
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* the set.
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*/
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if (!NoAssign) {
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S = va_arg (ap, char*);
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while (IsCharInSet (C) && Width--) {
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*S++ = C;
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ReadChar ();
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}
|
|
*S = '\0';
|
|
} else {
|
|
while (IsCharInSet (C) && Width--) {
|
|
ReadChar ();
|
|
}
|
|
}
|
|
++Conversions;
|
|
break;
|
|
|
|
case 'p':
|
|
/* Pointer, format is 0xABCD */
|
|
SkipWhite ();
|
|
if (CHAR (C) != '0') {
|
|
Error (RC_NOCONV);
|
|
}
|
|
ReadChar ();
|
|
if (CHAR (C) != 'x' && CHAR (C) != 'X') {
|
|
Error (RC_NOCONV);
|
|
}
|
|
ReadChar ();
|
|
if (ReadInt (16) != 4) { /* 4 chars expected */
|
|
Error (RC_NOCONV);
|
|
}
|
|
AssignInt ();
|
|
++Conversions;
|
|
break;
|
|
|
|
case 'n':
|
|
/* Store characters consumed so far */
|
|
IntVal = CharCount;
|
|
AssignInt ();
|
|
break;
|
|
|
|
default:
|
|
/* Invalid conversion */
|
|
Error (RC_NOCONV);
|
|
break;
|
|
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Push back the last unused character, provided it is not EOF */
|
|
if (C != EOF) {
|
|
D->unget (C, D->data);
|
|
}
|
|
|
|
} else {
|
|
|
|
/* Jump via JumpBuf means an error. If this happens at EOF with no
|
|
* conversions, it is considered an error, otherwise the number
|
|
* of conversions is returned (the default behaviour).
|
|
*/
|
|
if (C == EOF && CharCount == 0) {
|
|
/* Special case: error */
|
|
Conversions = EOF;
|
|
}
|
|
|
|
}
|
|
|
|
/* Return the number of conversions */
|
|
return Conversions;
|
|
}
|
|
|
|
|
|
|
|
|