1/*****************************************************************************/
2/* */
3/* istack.c */
4/* */
5/* Input stack for the scanner */
6/* */
7/* */
8/* */
9/* (C) 2000-2003 Ullrich von Bassewitz */
10/* Roemerstrasse 52 */
11/* D-70794 Filderstadt */
12/* EMail: uz@cc65.org */
13/* */
14/* */
15/* This software is provided 'as-is', without any expressed or implied */
16/* warranty. In no event will the authors be held liable for any damages */
17/* arising from the use of this software. */
18/* */
19/* Permission is granted to anyone to use this software for any purpose, */
20/* including commercial applications, and to alter it and redistribute it */
21/* freely, subject to the following restrictions: */
22/* */
23/* 1. The origin of this software must not be misrepresented; you must not */
24/* claim that you wrote the original software. If you use this software */
25/* in a product, an acknowledgment in the product documentation would be */
26/* appreciated but is not required. */
27/* 2. Altered source versions must be plainly marked as such, and must not */
28/* be misrepresented as being the original software. */
29/* 3. This notice may not be removed or altered from any source */
30/* distribution. */
31/* */
32/*****************************************************************************/
33
34
35
36/* common */
37#include "check.h"
38#include "xmalloc.h"
39
40/* ca65 */
41#include "error.h"
42#include "istack.h"
43
44
45
46/*****************************************************************************/
47/* Data */
48/*****************************************************************************/
49
50
51
52/* Size of the stack (== maximum nested macro or repeat count) */
53#define ISTACK_MAX 256
54
55/* Structure holding a stack element */
56typedef struct IElement IElement;
57struct IElement {
58 IElement* Next; /* Next stack element */
59 int (*Func)(void*); /* Function called for input */
60 void* Data; /* User data given as argument */
61 const char* Desc; /* Description */
62};
63
64/* The stack */
65static IElement* IStack = 0; /* Input stack pointer */
66static unsigned ICount = 0; /* Number of items on the stack */
67
68
69
70/*****************************************************************************/
71/* Code */
72/*****************************************************************************/
73
74
75
76void PushInput (int (*Func) (void*), void* Data, const char* Desc)
77/* Push an input function onto the input stack */
78{
79 IElement* E;
80
81 /* Check for a stack overflow */
82 if (ICount > ISTACK_MAX) {
83 Fatal ("Maximum input stack nesting exceeded");
84 }
85
86 /* Create a new stack element */
87 E = xmalloc (sizeof (*E));
88
89 /* Initialize it */
90 E->Func = Func;
91 E->Data = Data;
92 E->Desc = Desc;
93
94 /* Push it */
95 E->Next = IStack;
96 IStack = E;
97}
98
99
100
101void PopInput (void)
102/* Pop the current input function from the input stack */
103{
104 IElement* E;
105
106 /* We cannot pop from an empty stack */
107 PRECONDITION (IStack != 0);
108
109 /* Remember the last element */
110 E = IStack;
111
112 /* Pop it */
113 IStack = IStack->Next;
114
115 /* And delete it */
116 xfree (E);
117}
118
119
120
121int InputFromStack (void)
122/* Try to get input from the input stack. Return true if we had such input,
123** return false otherwise.
124*/
125{
126 /* Repeatedly call the TOS routine until we have a token or if run out of
127 ** routines.
128 */
129 while (IStack) {
130 if (IStack->Func (IStack->Data) != 0) {
131 /* We have a token */
132 return 1;
133 }
134 }
135
136 /* Nothing is on the stack */
137 return 0;
138}
139
140
141
142int HavePushedInput (void)
143/* Return true if we have stacked input available, return false if not */
144{
145 return (IStack != 0);
146}
147
148
149
150void CheckInputStack (void)
151/* Called from the scanner before closing an input file. Will check for any
152** stuff on the input stack.
153*/
154{
155 if (IStack) {
156 Error ("Open %s", IStack->Desc);
157 }
158}
159