From 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:51 +0200 Subject: Adding upstream version 2.06. Signed-off-by: Daniel Baumann --- include/grub/buffer.h | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 include/grub/buffer.h (limited to 'include/grub/buffer.h') diff --git a/include/grub/buffer.h b/include/grub/buffer.h new file mode 100644 index 0000000..bb5e3cd --- /dev/null +++ b/include/grub/buffer.h @@ -0,0 +1,144 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2021 Free Software Foundation, Inc. + * + * GRUB 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. + * + * GRUB 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 GRUB. If not, see . + */ + +#ifndef GRUB_BUFFER_H +#define GRUB_BUFFER_H 1 + +#include +#include +#include +#include +#include + +struct grub_buffer +{ + grub_uint8_t *data; + grub_size_t sz; + grub_size_t pos; + grub_size_t used; +}; + +/* + * grub_buffer_t represents a simple variable sized byte buffer with + * read and write cursors. It currently only implements + * functionality required by the only user in GRUB (append byte[s], + * peeking data at a specified position and updating the read cursor. + * Some things that this doesn't do yet are: + * - Reading a portion of the buffer by copying data from the current + * read position in to a caller supplied destination buffer and then + * automatically updating the read cursor. + * - Dropping the read part at the start of the buffer when an append + * requires more space. + */ +typedef struct grub_buffer *grub_buffer_t; + +/* Allocate a new buffer with the specified initial size. */ +extern grub_buffer_t grub_buffer_new (grub_size_t sz); + +/* Free the buffer and its resources. */ +extern void grub_buffer_free (grub_buffer_t buf); + +/* Return the number of unread bytes in this buffer. */ +static inline grub_size_t +grub_buffer_get_unread_bytes (grub_buffer_t buf) +{ + return buf->used - buf->pos; +} + +/* + * Ensure that the buffer size is at least the requested + * number of bytes. + */ +extern grub_err_t grub_buffer_ensure_space (grub_buffer_t buf, grub_size_t req); + +/* + * Append the specified number of bytes from the supplied + * data to the buffer. + */ +static inline grub_err_t +grub_buffer_append_data (grub_buffer_t buf, const void *data, grub_size_t len) +{ + grub_size_t req; + + if (grub_add (buf->used, len, &req)) + return grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected")); + + if (grub_buffer_ensure_space (buf, req) != GRUB_ERR_NONE) + return grub_errno; + + grub_memcpy (&buf->data[buf->used], data, len); + buf->used = req; + + return GRUB_ERR_NONE; +} + +/* Append the supplied character to the buffer. */ +static inline grub_err_t +grub_buffer_append_char (grub_buffer_t buf, char c) +{ + return grub_buffer_append_data (buf, &c, 1); +} + +/* + * Forget and return the underlying data buffer. The caller + * becomes the owner of this buffer, and must free it when it + * is no longer required. + */ +extern void *grub_buffer_take_data (grub_buffer_t buf); + +/* Reset this buffer. Note that this does not deallocate any resources. */ +void grub_buffer_reset (grub_buffer_t buf); + +/* + * Return a pointer to the underlying data buffer at the specified + * offset from the current read position. Note that this pointer may + * become invalid if the buffer is mutated further. + */ +static inline void * +grub_buffer_peek_data_at (grub_buffer_t buf, grub_size_t off) +{ + if (grub_add (buf->pos, off, &off)) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected")); + return NULL; + } + + if (off >= buf->used) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, N_("peek out of range")); + return NULL; + } + + return &buf->data[off]; +} + +/* + * Return a pointer to the underlying data buffer at the current + * read position. Note that this pointer may become invalid if the + * buffer is mutated further. + */ +static inline void * +grub_buffer_peek_data (grub_buffer_t buf) +{ + return grub_buffer_peek_data_at (buf, 0); +} + +/* Advance the read position by the specified number of bytes. */ +extern grub_err_t grub_buffer_advance_read_pos (grub_buffer_t buf, grub_size_t n); + +#endif /* GRUB_BUFFER_H */ -- cgit v1.2.3