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 | |
53 | void 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 | |
63 | void 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 | |
72 | void 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 | |
83 | void 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 | |
103 | void 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 | |
113 | void 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 | |
123 | unsigned 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 | |
135 | unsigned 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 | |
145 | unsigned 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 | |
155 | unsigned 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 | |
179 | char* 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 | |
196 | void* 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 | |