lib/buffer: add possibility to save position in the buffer

This is necessary to use lib/buffer.c in libsmart cols.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/include/buffer.h b/include/buffer.h
index 4163e0d752439cf082f24dd8707a7aa4d6c8dcc6..5c081fb81f6a55a3d7895926e97762c3c4e23265 100644 (file)
--- a/include/buffer.h
+++ b/include/buffer.h
@@ -9,6 +9,9 @@ struct ul_buffer {
 
        size_t sz;              /* allocated space for data */
        size_t chunksize;
+
+       char **ptrs;            /* saved pointers */
+       size_t nptrs;           /* number of saved poiters */
 };
 
 #define UL_INIT_BUFFER { .begin = NULL }
@@ -26,4 +29,9 @@ int ul_buffer_set_data(struct ul_buffer *buf, const char *data, size_t sz);
 char *ul_buffer_get_data(struct ul_buffer *buf,  size_t *sz);
 size_t ul_buffer_get_bufsiz(struct ul_buffer *buf);
 
+int ul_buffer_save_pointer(struct ul_buffer *buf, unsigned short ptr_idx);
+char *ul_buffer_get_pointer(struct ul_buffer *buf, unsigned short  ptr_idx);
+size_t ul_buffer_get_pointer_length(struct ul_buffer *buf, unsigned short ptr_idx);
+
+
 #endif /* UTIL_LINUX_BUFFER */

diff --git a/lib/buffer.c b/lib/buffer.c
index 80374e5a89e0584e0b1598d849c4642079df90f1..3c112dd9de6174146272dbcd7f24ae684e6eec8c 100644 (file)
--- a/lib/buffer.c
+++ b/lib/buffer.c
@@ -11,6 +11,7 @@ void ul_buffer_reset_data(struct ul_buffer *buf)
        if (buf->begin)
                buf->begin[0] = '\0';
        buf->end = buf->begin;
+       memset(buf->ptrs, 0, buf->nptrs * sizeof(char *));
 }
 
 void ul_buffer_free_data(struct ul_buffer *buf)
@@ -21,6 +22,10 @@ void ul_buffer_free_data(struct ul_buffer *buf)
        buf->begin = NULL;
        buf->end = NULL;
        buf->sz = 0;
+
+       free(buf->ptrs);
+       buf->ptrs = NULL;
+       buf->nptrs = 0;
 }
 
 void ul_buffer_set_chunksize(struct ul_buffer *buf, size_t sz)
@@ -33,6 +38,39 @@ int ul_buffer_is_empty(struct ul_buffer *buf)
        return buf->begin == buf->end;
 }
 
+int ul_buffer_save_pointer(struct ul_buffer *buf, unsigned short ptr_idx)
+{
+       if (ptr_idx >= buf->nptrs) {
+               char **tmp = realloc(buf->ptrs, (ptr_idx + 1) * sizeof(char *));
+
+               if (!tmp)
+                       return -EINVAL;
+               buf->ptrs = tmp;
+               buf->nptrs = ptr_idx + 1;
+       }
+
+       buf->ptrs[ptr_idx] = buf->end;
+       return 0;
+}
+
+
+char *ul_buffer_get_pointer(struct ul_buffer *buf, unsigned short ptr_idx)
+{
+       if (ptr_idx < buf->nptrs)
+               return buf->ptrs[ptr_idx];
+       return NULL;
+}
+
+size_t ul_buffer_get_pointer_length(struct ul_buffer *buf, unsigned short ptr_idx)
+{
+       char *ptr = ul_buffer_get_pointer(buf, ptr_idx);
+
+       if (ptr)
+               return ptr - buf->begin;
+       return 0;
+}
+
+
 void ul_buffer_refer_string(struct ul_buffer *buf, char *str)
 {
        if (buf->sz)
@@ -134,6 +172,12 @@ size_t ul_buffer_get_bufsiz(struct ul_buffer *buf)
 
 
 #ifdef TEST_PROGRAM_BUFFER
+
+enum {
+       PTR_AAA  = 0,
+       PTR_BBB,
+};
+
 int main(void)
 {
        struct ul_buffer buf = UL_INIT_BUFFER;
@@ -145,19 +189,28 @@ int main(void)
        ul_buffer_append_string(&buf, "AAA");
        ul_buffer_append_data(&buf, "=", 1);
        ul_buffer_append_string(&buf, "aaa");
+       ul_buffer_save_pointer(&buf, PTR_AAA);
+
        ul_buffer_append_data(&buf, ",", 1);
        ul_buffer_append_string(&buf, "BBB");
        ul_buffer_append_string(&buf, "=");
        ul_buffer_append_string(&buf, "bbb");
+       ul_buffer_save_pointer(&buf, PTR_BBB);
 
        str = ul_buffer_get_data(&buf, &sz);
        printf("data [%zu] '%s'\n", sz, str);
 
+       printf(" pointer data len: AAA=%zu, BBB=%zu\n",
+                       ul_buffer_get_pointer_length(&buf, PTR_AAA),
+                       ul_buffer_get_pointer_length(&buf, PTR_BBB));
+
        ul_buffer_reset_data(&buf);
        ul_buffer_append_string(&buf, "This is really long string to test the buffer function.");
+       ul_buffer_save_pointer(&buf, PTR_AAA);
        ul_buffer_append_string(&buf, " YES!");
        str = ul_buffer_get_data(&buf, &sz);
        printf("data [%zu] '%s'\n", sz, str);
+       printf(" pointer data len: AAA=%zu\n", ul_buffer_get_pointer_length(&buf, PTR_AAA));
 
        ul_buffer_free_data(&buf);
        str = strdup("foo");