6  * This library is free software; you can redistribute it and/or
9  * version 2.1 of the License, or (at your option) any later version.
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
22 #include "qemu/host-utils.h"
26 #define BUFFER_MIN_INIT_SIZE     4096
27 #define BUFFER_MIN_SHRINK_SIZE  65536
29 /* define the factor alpha for the exponential smoothing
32 #define BUFFER_AVG_SIZE_SHIFT       7
34 static size_t buffer_req_size(Buffer *buffer, size_t len)  in buffer_req_size()  argument
37                pow2ceil(buffer->offset + len));  in buffer_req_size()
40 static void buffer_adj_size(Buffer *buffer, size_t len)  in buffer_adj_size()  argument
42     size_t old = buffer->capacity;  in buffer_adj_size()
43     buffer->capacity = buffer_req_size(buffer, len);  in buffer_adj_size()
44     buffer->buffer = g_realloc(buffer->buffer, buffer->capacity);  in buffer_adj_size()
45     trace_buffer_resize(buffer->name ?: "unnamed",  in buffer_adj_size()
46                         old, buffer->capacity);  in buffer_adj_size()
50     buffer->avg_size = MAX(buffer->avg_size,  in buffer_adj_size()
51                            buffer->capacity << BUFFER_AVG_SIZE_SHIFT);  in buffer_adj_size()
59     buffer->name = g_strdup_vprintf(name, ap);  in buffer_init()
65     return buffer->avg_size >> BUFFER_AVG_SIZE_SHIFT;  in buffer_get_avg_size()
73      * avg_size = avg_size * ( 1 - a ) + required_size * a  in buffer_shrink()
75     buffer->avg_size *= (1 << BUFFER_AVG_SIZE_SHIFT) - 1;  in buffer_shrink()
76     buffer->avg_size >>= BUFFER_AVG_SIZE_SHIFT;  in buffer_shrink()
77     buffer->avg_size += buffer_req_size(buffer, 0);  in buffer_shrink()
83     if (new < buffer->capacity >> 3 &&  in buffer_shrink()
91 void buffer_reserve(Buffer *buffer, size_t len)  in buffer_reserve()  argument
93     if ((buffer->capacity - buffer->offset) < len) {  in buffer_reserve()
94         buffer_adj_size(buffer, len);  in buffer_reserve()
100     return buffer->offset == 0;  in buffer_empty()
105     return buffer->buffer + buffer->offset;  in buffer_end()
110     buffer->offset = 0;  in buffer_reset()
116     trace_buffer_free(buffer->name ?: "unnamed", buffer->capacity);  in buffer_free()
117     g_free(buffer->buffer);  in buffer_free()
118     g_free(buffer->name);  in buffer_free()
119     buffer->offset = 0;  in buffer_free()
120     buffer->capacity = 0;  in buffer_free()
121     buffer->buffer = NULL;  in buffer_free()
122     buffer->name = NULL;  in buffer_free()
125 void buffer_append(Buffer *buffer, const void *data, size_t len)  in buffer_append()  argument
127     memcpy(buffer->buffer + buffer->offset, data, len);  in buffer_append()
128     buffer->offset += len;  in buffer_append()
131 void buffer_advance(Buffer *buffer, size_t len)  in buffer_advance()  argument
133     memmove(buffer->buffer, buffer->buffer + len,  in buffer_advance()
134             (buffer->offset - len));  in buffer_advance()
135     buffer->offset -= len;  in buffer_advance()
141     trace_buffer_move_empty(to->name ?: "unnamed",  in buffer_move_empty()
142                             from->offset,  in buffer_move_empty()
143                             from->name ?: "unnamed");  in buffer_move_empty()
144     assert(to->offset == 0);  in buffer_move_empty()
146     g_free(to->buffer);  in buffer_move_empty()
147     to->offset = from->offset;  in buffer_move_empty()
148     to->capacity = from->capacity;  in buffer_move_empty()
149     to->buffer = from->buffer;  in buffer_move_empty()
151     from->offset = 0;  in buffer_move_empty()
152     from->capacity = 0;  in buffer_move_empty()
153     from->buffer = NULL;  in buffer_move_empty()
158     if (to->offset == 0) {  in buffer_move()
163     trace_buffer_move(to->name ?: "unnamed",  in buffer_move()
164                       from->offset,  in buffer_move()
165                       from->name ?: "unnamed");  in buffer_move()
166     buffer_reserve(to, from->offset);  in buffer_move()
167     buffer_append(to, from->buffer, from->offset);  in buffer_move()
169     g_free(from->buffer);  in buffer_move()
170     from->offset = 0;  in buffer_move()
171     from->capacity = 0;  in buffer_move()
172     from->buffer = NULL;  in buffer_move()