1 #include "cache.h" 2 #include <linux/kernel.h> 3 4 int prefixcmp(const char *str, const char *prefix) 5 { 6 for (; ; str++, prefix++) 7 if (!*prefix) 8 return 0; 9 else if (*str != *prefix) 10 return (unsigned char)*prefix - (unsigned char)*str; 11 } 12 13 /* 14 * Used as the default ->buf value, so that people can always assume 15 * buf is non NULL and ->buf is NUL terminated even for a freshly 16 * initialized strbuf. 17 */ 18 char strbuf_slopbuf[1]; 19 20 void strbuf_init(struct strbuf *sb, ssize_t hint) 21 { 22 sb->alloc = sb->len = 0; 23 sb->buf = strbuf_slopbuf; 24 if (hint) 25 strbuf_grow(sb, hint); 26 } 27 28 void strbuf_release(struct strbuf *sb) 29 { 30 if (sb->alloc) { 31 zfree(&sb->buf); 32 strbuf_init(sb, 0); 33 } 34 } 35 36 char *strbuf_detach(struct strbuf *sb, size_t *sz) 37 { 38 char *res = sb->alloc ? sb->buf : NULL; 39 if (sz) 40 *sz = sb->len; 41 strbuf_init(sb, 0); 42 return res; 43 } 44 45 void strbuf_grow(struct strbuf *sb, size_t extra) 46 { 47 if (sb->len + extra + 1 <= sb->len) 48 die("you want to use way too much memory"); 49 if (!sb->alloc) 50 sb->buf = NULL; 51 ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc); 52 } 53 54 static void strbuf_splice(struct strbuf *sb, size_t pos, size_t len, 55 const void *data, size_t dlen) 56 { 57 if (pos + len < pos) 58 die("you want to use way too much memory"); 59 if (pos > sb->len) 60 die("`pos' is too far after the end of the buffer"); 61 if (pos + len > sb->len) 62 die("`pos + len' is too far after the end of the buffer"); 63 64 if (dlen >= len) 65 strbuf_grow(sb, dlen - len); 66 memmove(sb->buf + pos + dlen, 67 sb->buf + pos + len, 68 sb->len - pos - len); 69 memcpy(sb->buf + pos, data, dlen); 70 strbuf_setlen(sb, sb->len + dlen - len); 71 } 72 73 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len) 74 { 75 strbuf_splice(sb, pos, len, NULL, 0); 76 } 77 78 void strbuf_add(struct strbuf *sb, const void *data, size_t len) 79 { 80 strbuf_grow(sb, len); 81 memcpy(sb->buf + sb->len, data, len); 82 strbuf_setlen(sb, sb->len + len); 83 } 84 85 void strbuf_addf(struct strbuf *sb, const char *fmt, ...) 86 { 87 int len; 88 va_list ap; 89 90 if (!strbuf_avail(sb)) 91 strbuf_grow(sb, 64); 92 va_start(ap, fmt); 93 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap); 94 va_end(ap); 95 if (len < 0) 96 die("your vsnprintf is broken"); 97 if (len > strbuf_avail(sb)) { 98 strbuf_grow(sb, len); 99 va_start(ap, fmt); 100 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap); 101 va_end(ap); 102 if (len > strbuf_avail(sb)) { 103 die("this should not happen, your vsnprintf is broken"); 104 } 105 } 106 strbuf_setlen(sb, sb->len + len); 107 } 108 109 ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint) 110 { 111 size_t oldlen = sb->len; 112 size_t oldalloc = sb->alloc; 113 114 strbuf_grow(sb, hint ? hint : 8192); 115 for (;;) { 116 ssize_t cnt; 117 118 cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1); 119 if (cnt < 0) { 120 if (oldalloc == 0) 121 strbuf_release(sb); 122 else 123 strbuf_setlen(sb, oldlen); 124 return -1; 125 } 126 if (!cnt) 127 break; 128 sb->len += cnt; 129 strbuf_grow(sb, 8192); 130 } 131 132 sb->buf[sb->len] = '\0'; 133 return sb->len - oldlen; 134 } 135