FlapJackApps/libdivecomputer
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Avoid undefined behaviour with NULL pointers.

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We accept NULL pointers if the size is zero, but the C standard
library functions memcpy and memmove requires valid pointers, even if
the size is zero.
This commit is contained in:
Jef Driesen 2009-11-10 11:35:19 +00:00
parent d3028dc2d7
commit 74272f4d77
1 changed files with 12 additions and 6 deletions
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18
src/buffer.c
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@ -91,7 +91,8 @@ dc_buffer_expand_append (dc_buffer_t *buffer, size_t n)
if (data == NULL)
return 0;
memcpy (data, buffer->data + buffer->offset, buffer->size);
if (buffer->size)
memcpy (data, buffer->data + buffer->offset, buffer->size);
free (buffer->data);
@ -99,7 +100,8 @@ dc_buffer_expand_append (dc_buffer_t *buffer, size_t n)
buffer->capacity = capacity;
buffer->offset = 0;
} else {
memmove (buffer->data, buffer->data + buffer->offset, buffer->size);
if (buffer->size)
memmove (buffer->data, buffer->data + buffer->offset, buffer->size);
buffer->offset = 0;
}
@ -122,7 +124,8 @@ dc_buffer_expand_prepend (dc_buffer_t *buffer, size_t n)
if (data == NULL)
return 0;
memcpy (data + capacity - buffer->size, buffer->data + buffer->offset, buffer->size);
if (buffer->size)
memcpy (data + capacity - buffer->size, buffer->data + buffer->offset, buffer->size);
free (buffer->data);
@ -130,7 +133,8 @@ dc_buffer_expand_prepend (dc_buffer_t *buffer, size_t n)
buffer->capacity = capacity;
buffer->offset = capacity - buffer->size;
} else {
memmove (buffer->data + available, buffer->data + buffer->offset, buffer->size);
if (buffer->size)
memmove (buffer->data + available, buffer->data + buffer->offset, buffer->size);
buffer->offset = available;
}
@ -184,7 +188,8 @@ dc_buffer_append (dc_buffer_t *buffer, const unsigned char data[], size_t size)
if (!dc_buffer_expand_append (buffer, buffer->size + size))
return 0;
memcpy (buffer->data + buffer->offset + buffer->size, data, size);
if (size)
memcpy (buffer->data + buffer->offset + buffer->size, data, size);
buffer->size += size;
@ -201,7 +206,8 @@ dc_buffer_prepend (dc_buffer_t *buffer, const unsigned char data[], size_t size)
if (!dc_buffer_expand_prepend (buffer, buffer->size + size))
return 0;
memcpy (buffer->data + buffer->offset - size, data, size);
if (size)
memcpy (buffer->data + buffer->offset - size, data, size);
buffer->size += size;
buffer->offset -= size;