mirror of
https://github.com/cjdelisle/cjdns
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85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
/* vim: set expandtab ts=4 sw=4: */
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/*
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* You may redistribute this program and/or modify it under the terms of
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* the GNU General Public License as published by the Free Software Foundation,
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* either version 3 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "io/Reader.h"
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#include "io/FileReader.h"
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#include "memory/Allocator.h"
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#include "util/Identity.h"
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#include <stdio.h>
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#include <stdint.h>
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struct FileReader {
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struct Reader generic;
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FILE* toRead;
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int failed;
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Identity
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};
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/** @see Reader->read() */
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static int read(struct Reader* reader, void* readInto, unsigned long length)
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{
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struct FileReader* context = Identity_check((struct FileReader*) reader);
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int peek = 0;
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if (length == 0) {
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peek = 1;
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length++;
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}
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if (context->failed || fread((char*)readInto, 1, length, context->toRead) != length) {
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context->failed = 1;
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return -1;
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}
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if (peek) {
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ungetc(((char*)readInto)[0], context->toRead);
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length--;
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}
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context->generic.bytesRead += length;
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return 0;
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}
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/** @see Reader->skip() */
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static void skip(struct Reader* reader, unsigned long length)
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{
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struct FileReader* context = Identity_check((struct FileReader*) reader);
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#define BUFF_SZ 256
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uint8_t buff[BUFF_SZ];
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// fseek() and ftell() are unreliable.
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size_t amount;
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while ((amount = (length > BUFF_SZ) ? BUFF_SZ : length) && !context->failed) {
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context->failed = read(reader, buff, amount);
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length -= amount;
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}
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}
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/** @see FileReader.h */
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struct Reader* FileReader_new(FILE* toRead, struct Allocator* allocator)
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{
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struct FileReader* context = Allocator_clone(allocator, (&(struct FileReader) {
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.generic = {
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.read = read,
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.skip = skip
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},
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.toRead = toRead
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}));
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Identity_set(context);
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return &context->generic;
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}
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