--- /dev/null
+/*
+ * region.c --- code which manages allocations within a region.
+ *
+ * Copyright (C) 2001 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <string.h>
+
+#include "e2fsck.h"
+
+struct region_el {
+ region_addr_t start;
+ region_addr_t end;
+ struct region_el *next;
+};
+
+struct region_struct {
+ region_addr_t min;
+ region_addr_t max;
+ struct region_el *allocated;
+};
+
+region_t region_create(region_addr_t min, region_addr_t max)
+{
+ region_t region;
+
+ region = malloc(sizeof(struct region_struct));
+ if (!region)
+ return NULL;
+ memset(region, 0, sizeof(struct region_struct));
+ region->min = min;
+ region->max = max;
+ return region;
+}
+
+void region_free(region_t region)
+{
+ struct region_el *r, *next;
+
+ for (r = region->allocated; r; r = next) {
+ next = r->next;
+ free(r);
+ }
+ memset(region, 0, sizeof(struct region_struct));
+ free(region);
+}
+
+int region_allocate(region_t region, region_addr_t start, int n)
+{
+ struct region_el *r, *new_region, *prev, *next;
+ region_addr_t end;
+
+ end = start+n;
+ if ((start < region->min) || (end > region->max))
+ return -1;
+ if (n == 0)
+ return 1;
+
+ /*
+ * Search through the linked list. If we find that it
+ * conflicts witih something that's already allocated, return
+ * 1; if we can find an existing region which we can grow, do
+ * so. Otherwise, stop when we find the appropriate place
+ * insert a new region element into the linked list.
+ */
+ for (r = region->allocated, prev=NULL; r; prev = r, r = r->next) {
+ if (((start >= r->start) && (start < r->end)) ||
+ ((end > r->start) && (end <= r->end)) ||
+ ((start <= r->start) && (end >= r->end)))
+ return 1;
+ if (end == r->start) {
+ r->start = start;
+ return 0;
+ }
+ if (start == r->end) {
+ if ((next = r->next)) {
+ if (end > next->start)
+ return 1;
+ if (end == next->start) {
+ r->end = next->end;
+ r->next = next->next;
+ free(next);
+ return 0;
+ }
+ }
+ r->end = end;
+ return 0;
+ }
+ if (start < r->start)
+ break;
+ }
+ /*
+ * Insert a new region element structure into the linked list
+ */
+ new_region = malloc(sizeof(struct region_el));
+ if (!new_region)
+ return -1;
+ new_region->start = start;
+ new_region->end = start + n;
+ new_region->next = r;
+ if (prev)
+ prev->next = new_region;
+ else
+ region->allocated = new_region;
+ return 0;
+}
+
+#ifdef TEST_PROGRAM
+#include <stdio.h>
+
+#define BCODE_END 0
+#define BCODE_CREATE 1
+#define BCODE_FREE 2
+#define BCODE_ALLOCATE 3
+#define BCODE_PRINT 4
+
+int bcode_program[] = {
+ BCODE_CREATE, 1, 1001,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 10, 10,
+ BCODE_ALLOCATE, 30, 10,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 1, 15,
+ BCODE_ALLOCATE, 15, 8,
+ BCODE_ALLOCATE, 1, 20,
+ BCODE_ALLOCATE, 1, 8,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 40, 10,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 22, 5,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 27, 3,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 20, 2,
+ BCODE_PRINT,
+ BCODE_ALLOCATE, 49, 1,
+ BCODE_ALLOCATE, 50, 5,
+ BCODE_ALLOCATE, 9, 2,
+ BCODE_ALLOCATE, 9, 1,
+ BCODE_PRINT,
+ BCODE_FREE,
+ BCODE_END
+};
+
+void region_print(region_t region, FILE *f)
+{
+ struct region_el *r;
+ int i = 0;
+
+ fprintf(f, "Printing region (min=%d. max=%d)\n\t", region->min,
+ region->max);
+ for (r = region->allocated; r; r = r->next) {
+ fprintf(f, "(%d, %d) ", r->start, r->end);
+ if (++i >= 8)
+ fprintf(f, "\n\t");
+ }
+ fprintf(f, "\n");
+}
+
+int main(int argc, char **argv)
+{
+ region_t r;
+ int pc = 0, ret;
+ region_addr_t start, end, len;
+
+
+ while (1) {
+ switch (bcode_program[pc++]) {
+ case BCODE_END:
+ exit(0);
+ case BCODE_CREATE:
+ start = bcode_program[pc++];
+ end = bcode_program[pc++];
+ printf("Creating region with args(%d, %d)\n",
+ start, end);
+ r = region_create(start, end);
+ if (!r) {
+ fprintf(stderr, "Couldn't create region.\n");
+ exit(1);
+ }
+ break;
+ case BCODE_ALLOCATE:
+ start = bcode_program[pc++];
+ end = bcode_program[pc++];
+ ret = region_allocate(r, start, end);
+ printf("Region_allocate(%d, %d) returns %d\n",
+ start, end, ret);
+ break;
+ case BCODE_PRINT:
+ region_print(r, stdout);
+ break;
+ }
+ }
+}
+
+#endif /* TEST_PROGRAM */
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff