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