diff options
| -rw-r--r-- | cop.h | 16 | ||||
| -rw-r--r-- | op.c | 52 |
2 files changed, 50 insertions, 18 deletions
@@ -534,7 +534,10 @@ string pv created with C<rcpv_new()>. Returns the refcount for a pv created with C<rcpv_new()>. =for apidoc Am|RCPV *|RCPV_LEN|char *pv -Returns the length of a pv created with C<rcpv_new()>. +Returns the length of a pv created with C<rcpv_new()>. +Note that this reflects the length of the string from the callers +point of view, it does not include the mandatory null which is +always injected at the end of the string by rcpv_new(). =cut */ @@ -542,16 +545,19 @@ Returns the length of a pv created with C<rcpv_new()>. struct rcpv { STRLEN refcount; /* UV would mean a 64 refcnt on 32 bit builds with -Duse64bitint */ - STRLEN len; + STRLEN len; /* length of string including mandatory + null byte at end */ char pv[1]; }; typedef struct rcpv RCPV; -#define RCPVf_USE_STRLEN 1 -#define RCPVf_NO_COPY 2 +#define RCPVf_USE_STRLEN (1 << 0) +#define RCPVf_NO_COPY (1 << 1) +#define RCPVf_ALLOW_EMPTY (1 << 2) + #define RCPVx(pv_arg) ((RCPV *)((pv_arg) - STRUCT_OFFSET(struct rcpv, pv))) #define RCPV_REFCOUNT(pv) (RCPVx(pv)->refcount) -#define RCPV_LEN(pv) (RCPVx(pv)->len) +#define RCPV_LEN(pv) (RCPVx(pv)->len-1) /* len always includes space for a null */ #ifdef USE_ITHREADS @@ -15255,16 +15255,32 @@ Perl_dup_warnings(pTHX_ char* warnings) /* =for apidoc rcpv_new -Create a new shared memory refcounted string from the argument. If flags is set -to RCPVf_USE_STRLEN then the len argument is ignored and set using strlen(pv). -If the pv is NULL returns NULL. The newly created string will have a refcount -of 1, and is suitable for passing into rcpv_copy() and rcpv_free(). To access -the RCPV * from the returned value use the RCPVx() macro. +Create a new shared memory refcounted string with the requested size, and +with the requested initialization and a refcount of 1. The actual space +allocated will be 1 byte more than requested and rcpv_new() will ensure that +the extra byte is a null regardless of any flags settings. -Note that rcpv_new() does NOT use a hash table or anything like that to dedupe -inputs given the same text content. Each call with a non-null pv parameter -will produce a distinct pointer with its own refcount regardless of the input -content. +If the RCPVf_NO_COPY flag is set then the pv argument will be +ignored, otherwise the contents of the pv pointer will be copied into +the new buffer or if it is NULL the function will do nothing and return NULL. + +If the RCPVf_USE_STRLEN flag is set then the len argument is ignored and +recomputed using C<strlen(pv)>. It is an error to combine RCPVf_USE_STRLEN +and RCPVf_NO_COPY at the same time. + +Under DEBUGGING rcpv_new() will assert() if it is asked to create a 0 length +shared string unless the RCPVf_ALLOW_EMPTY flag is set. + +The return value from the function is suitable for passing into rcpv_copy() and +rcpv_free(). To access the RCPV * from the returned value use the RCPVx() macro. +The 'len' member of the RCPV struct stores the allocated length (including the +extra byte), but the RCPV_LEN() macro returns the requested length (not +including the extra byte). + +Note that rcpv_new() does NOT use a hash table or anything like that to +dedupe inputs given the same text content. Each call with a non-null pv +parameter will produce a distinct pointer with its own refcount regardless of +the input content. =cut */ @@ -15277,23 +15293,32 @@ Perl_rcpv_new(pTHX_ const char *pv, STRLEN len, U32 flags) { PERL_UNUSED_CONTEXT; + /* Musn't use both at the same time */ + assert((flags & (RCPVf_NO_COPY|RCPVf_USE_STRLEN))!= + (RCPVf_NO_COPY|RCPVf_USE_STRLEN)); + if (!pv && (flags & RCPVf_NO_COPY) == 0) return NULL; if (flags & RCPVf_USE_STRLEN) len = strlen(pv); - rcpv = (RCPV *)PerlMemShared_malloc(sizeof(struct rcpv) + len + 1); + assert(len || (flags & RCPVf_ALLOW_EMPTY)); + + len++; /* add one for the null we will add to the end */ + + rcpv = (RCPV *)PerlMemShared_malloc(sizeof(struct rcpv) + len); if (!rcpv) croak_no_mem(); - rcpv->len = len; + rcpv->len = len; /* store length including null, + RCPV_LEN() subtracts 1 to account for this */ rcpv->refcount = 1; if ((flags & RCPVf_NO_COPY) == 0) { - (void)memcpy(rcpv->pv, pv, len); - rcpv->pv[len]= '\0'; + (void)memcpy(rcpv->pv, pv, len-1); } + rcpv->pv[len-1]= '\0'; /* the last byte should always be null */ return rcpv->pv; } @@ -15324,6 +15349,7 @@ Perl_rcpv_free(pTHX_ char *pv) { return NULL; RCPV *rcpv = RCPVx(pv); + assert(rcpv->refcount); assert(rcpv->len); OP_REFCNT_LOCK; |