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cc65/src/cc65/scanstrbuf.c
2021-03-03 10:07:24 +01:00

349 lines
10 KiB
C

/*****************************************************************************/
/* */
/* scanstrbuf.c */
/* */
/* Small scanner for input from a StrBuf */
/* */
/* */
/* */
/* (C) 2002-2009, Ullrich von Bassewitz */
/* Roemerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* common */
#include "chartype.h"
#include "tgttrans.h"
/* cc65 */
#include "datatype.h"
#include "error.h"
#include "hexval.h"
#include "ident.h"
#include "scanstrbuf.h"
/*****************************************************************************/
/* Helper functions */
/*****************************************************************************/
static int ParseChar (StrBuf* B)
/* Parse a character. Converts \n into EOL, etc. */
{
unsigned I;
unsigned Val;
int C;
/* Check for escape chars */
if ((C = SB_Get (B)) == '\\') {
switch (SB_Peek (B)) {
case '?':
C = '?';
SB_Skip (B);
break;
case 'a':
C = '\a';
SB_Skip (B);
break;
case 'b':
C = '\b';
SB_Skip (B);
break;
case 'f':
C = '\f';
SB_Skip (B);
break;
case 'r':
C = '\r';
SB_Skip (B);
break;
case 'n':
C = '\n';
SB_Skip (B);
break;
case 't':
C = '\t';
SB_Skip (B);
break;
case 'v':
C = '\v';
SB_Skip (B);
break;
case '\"':
C = '\"';
SB_Skip (B);
break;
case '\'':
C = '\'';
SB_Skip (B);
break;
case '\\':
C = '\\';
SB_Skip (B);
break;
case 'x':
case 'X':
/* Hex character constant */
SB_Skip (B);
C = HexVal (SB_Get (B)) << 4;
C |= HexVal (SB_Get (B));
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
/* Octal constant */
I = 0;
Val = SB_Get (B) - '0';
while (SB_Peek (B) >= '0' && SB_Peek (B) <= '7' && ++I <= 3) {
Val = (Val << 3) | (SB_Get (B) - '0');
}
C = (int) Val;
if (Val > 256) {
Error ("Character constant out of range");
C = ' ';
}
break;
default:
Error ("Illegal character constant 0x%02X", SB_Get (B));
C = ' ';
break;
}
}
/* Return the character */
return C;
}
/*****************************************************************************/
/* Code */
/*****************************************************************************/
void SB_SkipWhite (StrBuf* B)
/* Skip whitespace in the string buffer */
{
while (IsBlank (SB_Peek (B))) {
SB_Skip (B);
}
}
int SB_GetSym (StrBuf* B, StrBuf* Ident, const char* SpecialChars)
/* Get a symbol from the string buffer. If SpecialChars is not NULL, it
** points to a string that contains characters allowed within the string in
** addition to letters, digits and the underline. Note: The identifier must
** still begin with a letter.
** Returns 1 if a symbol was found and 0 otherwise but doesn't output any
** errors.
*/
{
/* Handle a NULL argument for SpecialChars transparently */
if (SpecialChars == 0) {
SpecialChars = "";
}
/* Clear Ident */
SB_Clear (Ident);
if (IsIdent (SB_Peek (B))) {
char C = SB_Peek (B);
do {
SB_AppendChar (Ident, C);
SB_Skip (B);
C = SB_Peek (B);
} while (IsIdent (C) || IsDigit (C) ||
(C != '\0' && strchr (SpecialChars, C) != 0));
SB_Terminate (Ident);
return 1;
} else {
return 0;
}
}
int SB_GetString (StrBuf* B, StrBuf* S)
/* Get a string from the string buffer. Returns 1 if a string was found and 0
** otherwise. Errors are only output in case of invalid strings (missing end
** of string).
*/
{
char C;
/* Clear S */
SB_Clear (S);
/* A string starts with quote marks */
if (SB_Peek (B) == '\"') {
/* String follows, be sure to concatenate strings */
while (SB_Peek (B) == '\"') {
/* Skip the quote char */
SB_Skip (B);
/* Read the actual string contents */
while ((C = SB_Peek (B)) != '\"') {
if (C == '\0') {
Error ("Unexpected end of string");
break;
}
SB_AppendChar (S, ParseChar (B));
}
/* Skip the closing quote char if there was one */
SB_Skip (B);
/* Skip white space, read new input */
SB_SkipWhite (B);
}
/* Terminate the string */
SB_Terminate (S);
/* Success */
return 1;
} else {
/* Not a string */
SB_Terminate (S);
return 0;
}
}
int SB_GetNumber (StrBuf* B, long* Val)
/* Get a number from the string buffer. Accepted formats are decimal, octal,
** hex and character constants. Numeric constants may be preceeded by a
** minus or plus sign. The function returns 1 if a number was found and
** zero otherwise. Errors are only output for invalid numbers.
*/
{
int Sign;
char C;
unsigned Base;
unsigned DigitVal;
/* Initialize Val */
*Val = 0;
/* Handle character constants */
if (SB_Peek (B) == '\'') {
/* Character constant */
SB_Skip (B);
*Val = SignExtendChar (TgtTranslateChar (ParseChar (B)));
if (SB_Peek (B) != '\'') {
Error ("'\'' expected");
return 0;
} else {
/* Skip the quote */
SB_Skip (B);
return 1;
}
}
/* Check for a sign. A sign must be followed by a digit, otherwise it's
** not a number
*/
Sign = 1;
switch (SB_Peek (B)) {
case '-':
Sign = -1;
/* FALLTHROUGH */
case '+':
if (!IsDigit (SB_LookAt (B, SB_GetIndex (B) + 1))) {
return 0;
}
SB_Skip (B);
break;
}
/* We must have a digit now, otherwise its not a number */
C = SB_Peek (B);
if (!IsDigit (C)) {
return 0;
}
/* Determine the base */
if (C == '0') {
/* Hex or octal */
SB_Skip (B);
if (tolower (SB_Peek (B)) == 'x') {
SB_Skip (B);
Base = 16;
if (!IsXDigit (SB_Peek (B))) {
Error ("Invalid hexadecimal number");
return 0;
}
} else {
Base = 8;
}
} else {
Base = 10;
}
/* Read the number */
while (IsXDigit (C = SB_Peek (B)) && (DigitVal = HexVal (C)) < Base) {
*Val = (*Val * Base) + DigitVal;
SB_Skip (B);
}
/* Allow optional 'U' and 'L' modifiers */
C = SB_Peek (B);
if (C == 'u' || C == 'U') {
SB_Skip (B);
C = SB_Peek (B);
if (C == 'l' || C == 'L') {
SB_Skip (B);
}
} else if (C == 'l' || C == 'L') {
SB_Skip (B);
C = SB_Peek (B);
if (C == 'u' || C == 'U') {
SB_Skip (B);
}
}
/* Success, value read is in Val */
*Val *= Sign;
return 1;
}