mem.c

   1 #include <stdarg.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include "mem.h"
   6
   7 #define MEMSZ           512
   8
   9 static void mem_extend(struct mem *mem)
  10 {
  11         char *s = mem->s;
  12         mem->sz = mem->sz ? mem->sz + mem->sz : MEMSZ;
  13         mem->s = malloc(mem->sz);
  14         if (mem->n)
  15                 memcpy(mem->s, s, mem->n);
  16         free(s);
  17 }
  18
  19 void mem_init(struct mem *mem)
  20 {
  21         memset(mem, 0, sizeof(*mem));
  22 }
  23
  24 void mem_done(struct mem *mem)
  25 {
  26         free(mem->s);
  27         memset(mem, 0, sizeof(*mem));
  28 }
  29
  30 void mem_cut(struct mem *mem, int pos)
  31 {
  32         mem->n = pos < mem->n ? pos : mem->n;
  33 }
  34
  35 void mem_cpy(struct mem *mem, int off, void *buf, int len)
  36 {
  37         memcpy(mem->s + off, buf, len);
  38 }
  39
  40 void mem_put(struct mem *mem, void *buf, int len)
  41 {
  42         while (mem->n + len + 1 >= mem->sz)
  43                 mem_extend(mem);
  44         mem_cpy(mem, mem->n, buf, len);
  45         mem->n += len;
  46 }
  47
  48 void mem_putc(struct mem *mem, int c)
  49 {
  50         if (mem->n + 2 >= mem->sz)
  51                 mem_extend(mem);
  52         mem->s[mem->n++] = c;
  53 }
  54
  55 void mem_putz(struct mem *mem, int sz)
  56 {
  57         while (mem->n + sz + 1 >= mem->sz)
  58                 mem_extend(mem);
  59         memset(mem->s + mem->n, 0, sz);
  60         mem->n += sz;
  61 }
  62
  63 /* return a pointer to mem's buffer; valid as long as mem is not modified */
  64 void *mem_buf(struct mem *mem)
  65 {
  66         if (!mem->s)
  67                 return "";
  68         mem->s[mem->n] = '\0';
  69         return mem->s;
  70 }
  71
  72 int mem_len(struct mem *mem)
  73 {
  74         return mem->n;
  75 }