Hands-off reader type

[disorder] / lib / hreader.h

diff --git a/lib/hreader.h b/lib/hreader.h
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+/*
+ * This file is part of DisOrder
+ * Copyright (C) 2010 Richard Kettlewell
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/** @file lib/hreader.h
+ * @brief Hands-off reader - read files without keeping them open
+ */
+#ifndef HREADER_H
+#define HREADER_H
+
+#include <unistd.h>
+
+/** @brief A hands-off reader
+ *
+ * Allows files to be read without holding them open.
+ */
+struct hreader {
+  const char *path;            /* file to read */
+  off_t offset;                        /* how far we've read so far */
+  char *buffer;                        /* input buffer */
+  size_t bufsize;              /* buffer size */
+  size_t bytes;                        /* size of last read */
+  size_t consumed;             /* bytes consumed by caller from last read */
+};
+
+/** @brief Initialize a hands-off reader
+ * @param path File to read
+ * @param h Reader to initialize
+ */
+void hreader_init(const char *path, struct hreader *h);
+
+/** @brief Read some bytes
+ * @param h Reader to read from
+ * @param buffer Where to store bytes
+ * @param n Maximum bytes to read
+ * @return Bytes read, or 0 at EOF, or -1 on error
+ */
+int hreader_read(struct hreader *h, void *buffer, size_t n);
+
+/** @brief Read more bytes
+ * @param h Reader to update
+ * @return Bytes available to read
+ *
+ * If not all bytes were consumed so far then just returns the number
+ * of bytes left to consume.
+ */
+int hreader_fill(struct hreader *h);
+
+/** @brief Consume some bytes
+ * @param h Reader to update
+ * @param n Bytes to consume
+ */
+void hreader_consume(struct hreader *h, size_t n);
+
+#endif /* HREADER_H */
+
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/