2 * region.c --- code which manages allocations within a region.
4 * Copyright (C) 2001 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Public
26 struct region_el *next;
29 struct region_struct {
32 struct region_el *allocated;
33 struct region_el *last;
36 region_t region_create(region_addr_t min, region_addr_t max)
40 region = malloc(sizeof(struct region_struct));
43 memset(region, 0, sizeof(struct region_struct));
50 void region_free(region_t region)
52 struct region_el *r, *next;
54 for (r = region->allocated; r; r = next) {
58 memset(region, 0, sizeof(struct region_struct));
62 int region_allocate(region_t region, region_addr_t start, int n)
64 struct region_el *r, *new_region, *prev, *next;
68 if ((start < region->min) || (end > region->max))
73 if (region->last && region->last->end == start &&
74 !region->last->next) {
75 region->last->end = end;
78 if (region->last && start > region->last->end &&
79 !region->last->next) {
86 * Search through the linked list. If we find that it
87 * conflicts with something that's already allocated, return
88 * 1; if we can find an existing region which we can grow, do
89 * so. Otherwise, stop when we find the appropriate place
90 * insert a new region element into the linked list.
92 for (r = region->allocated, prev=NULL; r; prev = r, r = r->next) {
93 if (((start >= r->start) && (start < r->end)) ||
94 ((end > r->start) && (end <= r->end)) ||
95 ((start <= r->start) && (end >= r->end)))
97 if (end == r->start) {
101 if (start == r->end) {
102 if ((next = r->next)) {
103 if (end > next->start)
105 if (end == next->start) {
107 r->next = next->next;
117 if (start < r->start)
121 * Insert a new region element structure into the linked list
124 new_region = malloc(sizeof(struct region_el));
127 new_region->start = start;
128 new_region->end = start + n;
129 new_region->next = r;
130 if (!new_region->next)
131 region->last = new_region;
133 prev->next = new_region;
135 region->allocated = new_region;
143 #define BCODE_CREATE 1
145 #define BCODE_ALLOCATE 3
146 #define BCODE_PRINT 4
148 int bcode_program[] = {
149 BCODE_CREATE, 1, 1001,
151 BCODE_ALLOCATE, 10, 10,
152 BCODE_ALLOCATE, 30, 10,
154 BCODE_ALLOCATE, 1, 15,
155 BCODE_ALLOCATE, 15, 8,
156 BCODE_ALLOCATE, 1, 20,
157 BCODE_ALLOCATE, 1, 8,
159 BCODE_ALLOCATE, 40, 10,
161 BCODE_ALLOCATE, 22, 5,
163 BCODE_ALLOCATE, 27, 3,
165 BCODE_ALLOCATE, 20, 2,
167 BCODE_ALLOCATE, 49, 1,
168 BCODE_ALLOCATE, 50, 5,
169 BCODE_ALLOCATE, 9, 2,
170 BCODE_ALLOCATE, 9, 1,
176 void region_print(region_t region, FILE *f)
181 fprintf(f, "Printing region (min=%llu. max=%llu)\n\t", region->min,
183 for (r = region->allocated; r; r = r->next) {
184 fprintf(f, "(%llu, %llu) ", r->start, r->end);
191 int main(int argc, char **argv)
195 region_addr_t start, end;
199 switch (bcode_program[pc++]) {
203 start = bcode_program[pc++];
204 end = bcode_program[pc++];
205 printf("Creating region with args(%llu, %llu)\n",
207 r = region_create(start, end);
209 fprintf(stderr, "Couldn't create region.\n");
214 start = bcode_program[pc++];
215 end = bcode_program[pc++];
216 ret = region_allocate(r, start, end);
217 printf("Region_allocate(%llu, %llu) returns %d\n",
221 region_print(r, stdout);
229 #endif /* TEST_PROGRAM */