mirror of https://github.com/cc65/cc65.git
159 lines
5.2 KiB
C
159 lines
5.2 KiB
C
/*****************************************************************************/
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/* */
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/* istack.c */
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/* */
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/* Input stack for the scanner */
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/* */
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/* */
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/* */
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/* (C) 2000-2003 Ullrich von Bassewitz */
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/* Roemerstrasse 52 */
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/* D-70794 Filderstadt */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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/* common */
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#include "check.h"
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#include "xmalloc.h"
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/* ca65 */
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#include "error.h"
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#include "istack.h"
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/*****************************************************************************/
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/* Data */
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/*****************************************************************************/
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/* Size of the stack (== maximum nested macro or repeat count) */
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#define ISTACK_MAX 256
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/* Structure holding a stack element */
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typedef struct IElement IElement;
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struct IElement {
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IElement* Next; /* Next stack element */
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int (*Func)(void*); /* Function called for input */
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void* Data; /* User data given as argument */
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const char* Desc; /* Description */
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};
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/* The stack */
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static IElement* IStack = 0; /* Input stack pointer */
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static unsigned ICount = 0; /* Number of items on the stack */
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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void PushInput (int (*Func) (void*), void* Data, const char* Desc)
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/* Push an input function onto the input stack */
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{
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IElement* E;
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/* Check for a stack overflow */
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if (ICount > ISTACK_MAX) {
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Fatal ("Maximum input stack nesting exceeded");
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}
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/* Create a new stack element */
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E = xmalloc (sizeof (*E));
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/* Initialize it */
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E->Func = Func;
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E->Data = Data;
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E->Desc = Desc;
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/* Push it */
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E->Next = IStack;
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IStack = E;
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}
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void PopInput (void)
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/* Pop the current input function from the input stack */
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{
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IElement* E;
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/* We cannot pop from an empty stack */
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PRECONDITION (IStack != 0);
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/* Remember the last element */
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E = IStack;
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/* Pop it */
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IStack = IStack->Next;
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/* And delete it */
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xfree (E);
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}
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int InputFromStack (void)
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/* Try to get input from the input stack. Return true if we had such input,
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** return false otherwise.
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*/
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{
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/* Repeatedly call the TOS routine until we have a token or if run out of
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** routines.
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*/
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while (IStack) {
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if (IStack->Func (IStack->Data) != 0) {
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/* We have a token */
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return 1;
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}
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}
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/* Nothing is on the stack */
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return 0;
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}
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int HavePushedInput (void)
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/* Return true if we have stacked input available, return false if not */
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{
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return (IStack != 0);
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}
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void CheckInputStack (void)
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/* Called from the scanner before closing an input file. Will check for any
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** stuff on the input stack.
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*/
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{
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if (IStack) {
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Error ("Open %s", IStack->Desc);
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}
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}
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