David 'Digit' Turner | 0a879bf | 2011-05-12 18:45:18 +0200 | [diff] [blame^] | 1 | /* Copyright (C) 2011 The Android Open Source Project |
| 2 | ** |
| 3 | ** This software is licensed under the terms of the GNU General Public |
| 4 | ** License version 2, as published by the Free Software Foundation, and |
| 5 | ** may be copied, distributed, and modified under those terms. |
| 6 | ** |
| 7 | ** This program is distributed in the hope that it will be useful, |
| 8 | ** but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | ** GNU General Public License for more details. |
| 11 | */ |
| 12 | #include <errno.h> |
| 13 | #include "android/utils/system.h" |
| 14 | #include "android/utils/assert.h" |
| 15 | #include "android/utils/lineinput.h" |
| 16 | |
| 17 | struct LineInput { |
| 18 | char* line; |
| 19 | size_t line_size; |
| 20 | int line_num; |
| 21 | int error; |
| 22 | int eof; |
| 23 | |
| 24 | struct { |
| 25 | FILE* file; |
| 26 | } std; |
| 27 | |
| 28 | char line0[128]; |
| 29 | }; |
| 30 | |
| 31 | /* Error codes returned by the internal line reading function(s) */ |
| 32 | enum { |
| 33 | LINEINPUT_ERROR = -1, |
| 34 | LINEINPUT_EOF = -2, |
| 35 | }; |
| 36 | |
| 37 | |
| 38 | static LineInput* |
| 39 | _lineInput_new( void ) |
| 40 | { |
| 41 | LineInput* input; |
| 42 | |
| 43 | ANEW0(input); |
| 44 | input->line = input->line0; |
| 45 | input->line_size = sizeof(input->line0); |
| 46 | |
| 47 | return input; |
| 48 | } |
| 49 | |
| 50 | /* Create a LineInput object that reads from a FILE* object */ |
| 51 | LineInput* |
| 52 | lineInput_newFromStdFile( FILE* file ) |
| 53 | { |
| 54 | LineInput* input = _lineInput_new(); |
| 55 | |
| 56 | input->std.file = file; |
| 57 | return input; |
| 58 | } |
| 59 | |
| 60 | /* Grow the line buffer a bit */ |
| 61 | static void |
| 62 | _lineInput_grow( LineInput* input ) |
| 63 | { |
| 64 | char* line; |
| 65 | |
| 66 | input->line_size += input->line_size >> 1; |
| 67 | line = input->line; |
| 68 | if (line == input->line0) |
| 69 | line = NULL; |
| 70 | |
| 71 | AARRAY_RENEW(line, input->line_size); |
| 72 | input->line = line; |
| 73 | } |
| 74 | |
| 75 | /* Forward declaration */ |
| 76 | static int _lineInput_getLineFromStdFile( LineInput* input, FILE* file ); |
| 77 | |
| 78 | const char* |
| 79 | lineInput_getLine( LineInput* input ) |
| 80 | { |
| 81 | return lineInput_getLineAndSize(input, NULL); |
| 82 | } |
| 83 | |
| 84 | const char* |
| 85 | lineInput_getLineAndSize( LineInput* input, size_t *pSize ) |
| 86 | { |
| 87 | int ret; |
| 88 | |
| 89 | /* be safe */ |
| 90 | if (pSize) |
| 91 | *pSize = 0; |
| 92 | |
| 93 | /* check parameters */ |
| 94 | if (input == NULL) { |
| 95 | errno = EINVAL; |
| 96 | return NULL; |
| 97 | } |
| 98 | |
| 99 | /* check state */ |
| 100 | if (input->error) { |
| 101 | return NULL; |
| 102 | } |
| 103 | if (input->eof) { |
| 104 | return NULL; |
| 105 | } |
| 106 | |
| 107 | ret = _lineInput_getLineFromStdFile(input, input->std.file); |
| 108 | if (ret >= 0) { |
| 109 | input->line_num += 1; |
| 110 | if (pSize != NULL) { |
| 111 | *pSize = ret; |
| 112 | return input->line; |
| 113 | } |
| 114 | return input->line; |
| 115 | } |
| 116 | if (ret == LINEINPUT_EOF) { |
| 117 | input->line_num += 1; |
| 118 | input->eof = 1; |
| 119 | return NULL; |
| 120 | } |
| 121 | if (ret == LINEINPUT_ERROR) { |
| 122 | input->error = errno; |
| 123 | return NULL; |
| 124 | } |
| 125 | AASSERT_UNREACHED(); |
| 126 | return NULL; |
| 127 | } |
| 128 | |
| 129 | /* Returns the number of the last line read by lineInput_getLine */ |
| 130 | int |
| 131 | lineInput_getLineNumber( LineInput* input ) |
| 132 | { |
| 133 | return input->line_num; |
| 134 | } |
| 135 | |
| 136 | /* Returns TRUE iff the end of file was reached */ |
| 137 | int |
| 138 | lineInput_isEof( LineInput* input ) |
| 139 | { |
| 140 | return (input->eof != 0); |
| 141 | } |
| 142 | |
| 143 | /* Return the error condition of a LineInput object. |
| 144 | * These are standard errno code for the last operation. |
| 145 | * Note: EOF corresponds to 0 here. |
| 146 | */ |
| 147 | int |
| 148 | lineInput_getError( LineInput* input ) |
| 149 | { |
| 150 | return input->error; |
| 151 | } |
| 152 | |
| 153 | void |
| 154 | lineInput_free( LineInput* input ) |
| 155 | { |
| 156 | if (input != NULL) { |
| 157 | if (input->line != NULL) { |
| 158 | if (input->line != input->line0) |
| 159 | AFREE(input->line); |
| 160 | input->line = NULL; |
| 161 | input->line_size = 0; |
| 162 | } |
| 163 | AFREE(input); |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | |
| 168 | /* Internal function used to read a new line from a FILE* using fgets(). |
| 169 | * We assume that this is more efficient than calling fgetc() in a loop. |
| 170 | * |
| 171 | * Return length of line, or either LINEINPUT_EOF / LINEINPUT_ERROR |
| 172 | */ |
| 173 | static int |
| 174 | _lineInput_getLineFromStdFile( LineInput* input, FILE* file ) |
| 175 | { |
| 176 | int offset = 0; |
| 177 | char* p; |
| 178 | |
| 179 | input->line[0] = '\0'; |
| 180 | |
| 181 | for (;;) { |
| 182 | char* buffer = input->line + offset; |
| 183 | int avail = input->line_size - offset; |
| 184 | |
| 185 | if (!fgets(buffer, avail, file)) { |
| 186 | /* We either reached the end of file or an i/o error occured. |
| 187 | * If we already read line data, just return it this time. |
| 188 | */ |
| 189 | if (offset > 0) { |
| 190 | return offset; |
| 191 | } |
| 192 | goto INPUT_ERROR; |
| 193 | } |
| 194 | |
| 195 | /* Find the terminating zero */ |
| 196 | p = memchr(buffer, '\0', avail); |
| 197 | AASSERT(p != NULL); |
| 198 | |
| 199 | if (p == buffer) { |
| 200 | /* This happens when the file has an embedded '\0', treat it |
| 201 | * as an eof, or bad things usually happen after that. */ |
| 202 | input->eof = 1; |
| 203 | if (offset > 0) |
| 204 | return offset; |
| 205 | else |
| 206 | return LINEINPUT_EOF; |
| 207 | } |
| 208 | |
| 209 | if (p[-1] != '\n' && p[-1] != '\r') { |
| 210 | /* This happens when the line is longer than our current buffer, |
| 211 | * so grow its size and try again. */ |
| 212 | offset = p - input->line; |
| 213 | _lineInput_grow(input); |
| 214 | continue; |
| 215 | } |
| 216 | |
| 217 | break; |
| 218 | } |
| 219 | |
| 220 | /* Get rid of trailing newline(s). Consider: \n, \r, and \r\n */ |
| 221 | if (p[-1] == '\n') { |
| 222 | p -= 1; |
| 223 | if (p > input->line && p[-1] == '\r') { |
| 224 | p -= 1; |
| 225 | } |
| 226 | p[0] = '\0'; |
| 227 | } |
| 228 | else if (p[-1] == '\r') { |
| 229 | p -= 1; |
| 230 | p[0] = '\0'; |
| 231 | } |
| 232 | |
| 233 | /* We did it */ |
| 234 | return (p - input->line); |
| 235 | |
| 236 | INPUT_ERROR: |
| 237 | if (feof(file)) { |
| 238 | input->eof = 1; |
| 239 | return LINEINPUT_EOF; |
| 240 | } |
| 241 | input->error = errno; |
| 242 | return LINEINPUT_ERROR; |
| 243 | } |
| 244 | |