1/*****************************************************************************/
2/* */
3/* fileio.c */
4/* */
5/* File I/O for the ar65 archiver */
6/* */
7/* */
8/* */
9/* (C) 1998-2003 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#include <string.h>
37
38/* common */
39#include "xmalloc.h"
40
41/* ar65 */
42#include "error.h"
43#include "fileio.h"
44
45
46
47/*****************************************************************************/
48/* Code */
49/*****************************************************************************/
50
51
52
53void Write8 (FILE* F, unsigned char Val)
54/* Write an 8 bit value to the file */
55{
56 if (putc (Val, F) == EOF) {
57 Error ("Write error (disk full?)");
58 }
59}
60
61
62
63void Write16 (FILE* F, unsigned Val)
64/* Write a 16 bit value to the file */
65{
66 Write8 (F, (unsigned char) Val);
67 Write8 (F, (unsigned char) (Val >> 8));
68}
69
70
71
72void Write32 (FILE* F, unsigned long Val)
73/* Write a 32 bit value to the file */
74{
75 Write8 (F, (unsigned char) Val);
76 Write8 (F, (unsigned char) (Val >> 8));
77 Write8 (F, (unsigned char) (Val >> 16));
78 Write8 (F, (unsigned char) (Val >> 24));
79}
80
81
82
83void WriteVar (FILE* F, unsigned long V)
84/* Write a variable sized value to the file in special encoding */
85{
86 /* We will write the value to the file in 7 bit chunks. If the 8th bit
87 ** is clear, we're done, if it is set, another chunk follows. This will
88 ** allow us to encode smaller values with less bytes, at the expense of
89 ** needing 5 bytes if a 32 bit value is written to file.
90 */
91 do {
92 unsigned char C = (V & 0x7F);
93 V >>= 7;
94 if (V) {
95 C |= 0x80;
96 }
97 Write8 (F, C);
98 } while (V != 0);
99}
100
101
102
103void WriteStr (FILE* F, const char* S)
104/* Write a string to the file */
105{
106 unsigned Len = strlen (S);
107 WriteVar (F, Len);
108 WriteData (F, S, Len);
109}
110
111
112
113void WriteData (FILE* F, const void* Data, unsigned Size)
114/* Write data to the file */
115{
116 if (fwrite (Data, 1, Size, F) != Size) {
117 Error ("Write error (disk full?)");
118 }
119}
120
121
122
123unsigned Read8 (FILE* F)
124/* Read an 8 bit value from the file */
125{
126 int C = getc (F);
127 if (C == EOF) {
128 Error ("Read error (file corrupt?)");
129 }
130 return C;
131}
132
133
134
135unsigned Read16 (FILE* F)
136/* Read a 16 bit value from the file */
137{
138 unsigned Lo = Read8 (F);
139 unsigned Hi = Read8 (F);
140 return (Hi << 8) | Lo;
141}
142
143
144
145unsigned long Read32 (FILE* F)
146/* Read a 32 bit value from the file */
147{
148 unsigned long Lo = Read16 (F);
149 unsigned long Hi = Read16 (F);
150 return (Hi << 16) | Lo;
151}
152
153
154
155unsigned long ReadVar (FILE* F)
156/* Read a variable size value from the file */
157{
158 /* The value was written to the file in 7 bit chunks LSB first. If there
159 ** are more bytes, bit 8 is set, otherwise it is clear.
160 */
161 unsigned char C;
162 unsigned long V = 0;
163 unsigned Shift = 0;
164 do {
165 /* Read one byte */
166 C = Read8 (F);
167 /* Encode it into the target value */
168 V |= ((unsigned long)(C & 0x7F)) << Shift;
169 /* Next value */
170 Shift += 7;
171 } while (C & 0x80);
172
173 /* Return the value read */
174 return V;
175}
176
177
178
179char* ReadStr (FILE* F)
180/* Read a string from the file (the memory will be malloc'ed) */
181{
182 /* Read the length */
183 unsigned Len = ReadVar (F);
184
185 /* Allocate memory and read the string itself */
186 char* S = xmalloc (Len + 1);
187 ReadData (F, S, Len);
188
189 /* Terminate the string and return it */
190 S [Len] = '\0';
191 return S;
192}
193
194
195
196void* ReadData (FILE* F, void* Data, unsigned Size)
197/* Read data from the file */
198{
199 if (fread (Data, 1, Size, F) != Size) {
200 Error ("Read error (file corrupt?)");
201 }
202 return Data;
203}
204