src/buffer.h

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #ifndef INCLUDE_buffer_h__
   8 #define INCLUDE_buffer_h__
   9
  10 #include "common.h"
  11 #include "git2/strarray.h"
  12 #include "git2/buffer.h"
  13
  14 /* typedef struct {
  15  *      char   *ptr;
  16  *      size_t asize, size;
  17  * } git_buf;
  18  */
  19
  20 extern char git_buf__initbuf[];
  21 extern char git_buf__oom[];
  22
  23 /* Use to initialize buffer structure when git_buf is on stack */
  24 #define GIT_BUF_INIT { git_buf__initbuf, 0, 0 }
  25
  26 GIT_INLINE(bool) git_buf_is_allocated(const git_buf *buf)
  27 {
  28         return (buf->ptr != NULL && buf->asize > 0);
  29 }
  30
  31 /**
  32  * Initialize a git_buf structure.
  33  *
  34  * For the cases where GIT_BUF_INIT cannot be used to do static
  35  * initialization.
  36  */
  37 extern void git_buf_init(git_buf *buf, size_t initial_size);
  38
  39 /**
  40  * Resize the buffer allocation to make more space.
  41  *
  42  * This will attempt to grow the buffer to accommodate the additional size.
  43  * It is similar to `git_buf_grow`, but performs the new size calculation,
  44  * checking for overflow.
  45  *
  46  * Like `git_buf_grow`, if this is a user-supplied buffer, this will allocate
  47  * a new buffer.
  48  */
  49 extern int git_buf_grow_by(git_buf *buffer, size_t additional_size);
  50
  51 /**
  52  * Attempt to grow the buffer to hold at least `target_size` bytes.
  53  *
  54  * If the allocation fails, this will return an error.  If `mark_oom` is true,
  55  * this will mark the buffer as invalid for future operations; if false,
  56  * existing buffer content will be preserved, but calling code must handle
  57  * that buffer was not expanded.  If `preserve_external` is true, then any
  58  * existing data pointed to be `ptr` even if `asize` is zero will be copied
  59  * into the newly allocated buffer.
  60  */
  61 extern int git_buf_try_grow(
  62         git_buf *buf, size_t target_size, bool mark_oom);
  63
  64 /**
  65  * Sanitizes git_buf structures provided from user input.  Users of the
  66  * library, when providing git_buf's, may wish to provide a NULL ptr for
  67  * ease of handling.  The buffer routines, however, expect a non-NULL ptr
  68  * always.  This helper method simply handles NULL input, converting to a
  69  * git_buf__initbuf.
  70  */
  71 extern void git_buf_sanitize(git_buf *buf);
  72
  73 extern void git_buf_swap(git_buf *buf_a, git_buf *buf_b);
  74 extern char *git_buf_detach(git_buf *buf);
  75 extern void git_buf_attach(git_buf *buf, char *ptr, size_t asize);
  76
  77 /* Populates a `git_buf` where the contents are not "owned" by the
  78  * buffer, and calls to `git_buf_free` will not free the given buf.
  79  */
  80 extern void git_buf_attach_notowned(
  81         git_buf *buf, const char *ptr, size_t size);
  82
  83 /**
  84  * Test if there have been any reallocation failures with this git_buf.
  85  *
  86  * Any function that writes to a git_buf can fail due to memory allocation
  87  * issues.  If one fails, the git_buf will be marked with an OOM error and
  88  * further calls to modify the buffer will fail.  Check git_buf_oom() at the
  89  * end of your sequence and it will be true if you ran out of memory at any
  90  * point with that buffer.
  91  *
  92  * @return false if no error, true if allocation error
  93  */
  94 GIT_INLINE(bool) git_buf_oom(const git_buf *buf)
  95 {
  96         return (buf->ptr == git_buf__oom);
  97 }
  98
  99 /*
 100  * Functions below that return int value error codes will return 0 on
 101  * success or -1 on failure (which generally means an allocation failed).
 102  * Using a git_buf where the allocation has failed with result in -1 from
 103  * all further calls using that buffer.  As a result, you can ignore the
 104  * return code of these functions and call them in a series then just call
 105  * git_buf_oom at the end.
 106  */
 107 int git_buf_sets(git_buf *buf, const char *string);
 108 int git_buf_putc(git_buf *buf, char c);
 109 int git_buf_putcn(git_buf *buf, char c, size_t len);
 110 int git_buf_put(git_buf *buf, const char *data, size_t len);
 111 int git_buf_puts(git_buf *buf, const char *string);
 112 int git_buf_printf(git_buf *buf, const char *format, ...) GIT_FORMAT_PRINTF(2, 3);
 113 int git_buf_vprintf(git_buf *buf, const char *format, va_list ap);
 114 void git_buf_clear(git_buf *buf);
 115 void git_buf_consume(git_buf *buf, const char *end);
 116 void git_buf_truncate(git_buf *buf, size_t len);
 117 void git_buf_shorten(git_buf *buf, size_t amount);
 118 void git_buf_rtruncate_at_char(git_buf *path, char separator);
 119
 120 /** General join with separator */
 121 int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...);
 122 /** Fast join of two strings - first may legally point into `buf` data */
 123 int git_buf_join(git_buf *buf, char separator, const char *str_a, const char *str_b);
 124 /** Fast join of three strings - cannot reference `buf` data */
 125 int git_buf_join3(git_buf *buf, char separator, const char *str_a, const char *str_b, const char *str_c);
 126
 127 /**
 128  * Join two strings as paths, inserting a slash between as needed.
 129  * @return 0 on success, -1 on failure
 130  */
 131 GIT_INLINE(int) git_buf_joinpath(git_buf *buf, const char *a, const char *b)
 132 {
 133         return git_buf_join(buf, '/', a, b);
 134 }
 135
 136 GIT_INLINE(const char *) git_buf_cstr(const git_buf *buf)
 137 {
 138         return buf->ptr;
 139 }
 140
 141 GIT_INLINE(size_t) git_buf_len(const git_buf *buf)
 142 {
 143         return buf->size;
 144 }
 145
 146 void git_buf_copy_cstr(char *data, size_t datasize, const git_buf *buf);
 147
 148 #define git_buf_PUTS(buf, str) git_buf_put(buf, str, sizeof(str) - 1)
 149
 150 GIT_INLINE(ssize_t) git_buf_rfind_next(const git_buf *buf, char ch)
 151 {
 152         ssize_t idx = (ssize_t)buf->size - 1;
 153         while (idx >= 0 && buf->ptr[idx] == ch) idx--;
 154         while (idx >= 0 && buf->ptr[idx] != ch) idx--;
 155         return idx;
 156 }
 157
 158 GIT_INLINE(ssize_t) git_buf_rfind(const git_buf *buf, char ch)
 159 {
 160         ssize_t idx = (ssize_t)buf->size - 1;
 161         while (idx >= 0 && buf->ptr[idx] != ch) idx--;
 162         return idx;
 163 }
 164
 165 GIT_INLINE(ssize_t) git_buf_find(const git_buf *buf, char ch)
 166 {
 167         void *found = memchr(buf->ptr, ch, buf->size);
 168         return found ? (ssize_t)((const char *)found - buf->ptr) : -1;
 169 }
 170
 171 /* Remove whitespace from the end of the buffer */
 172 void git_buf_rtrim(git_buf *buf);
 173
 174 int git_buf_cmp(const git_buf *a, const git_buf *b);
 175
 176 /* Write data as base64 encoded in buffer */
 177 int git_buf_encode_base64(git_buf *buf, const char *data, size_t len);
 178 /* Decode the given bas64 and write the result to the buffer */
 179 int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len);
 180
 181 /* Write data as "base85" encoded in buffer */
 182 int git_buf_encode_base85(git_buf *buf, const char *data, size_t len);
 183
 184 /*
 185  * Insert, remove or replace a portion of the buffer.
 186  *
 187  * @param buf The buffer to work with
 188  *
 189  * @param where The location in the buffer where the transformation
 190  * should be applied.
 191  *
 192  * @param nb_to_remove The number of chars to be removed. 0 to not
 193  * remove any character in the buffer.
 194  *
 195  * @param data A pointer to the data which should be inserted.
 196  *
 197  * @param nb_to_insert The number of chars to be inserted. 0 to not
 198  * insert any character from the buffer.
 199  *
 200  * @return 0 or an error code.
 201  */
 202 int git_buf_splice(
 203         git_buf *buf,
 204         size_t where,
 205         size_t nb_to_remove,
 206         const char *data,
 207         size_t nb_to_insert);
 208
 209 #endif