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#include "envp.h"
#include "string.h"
#include <stdlib.h>
extern char **environ;
static inline bool _envp_string_match_key(
const char *restrict string, const char *restrict key) {
for (size_t i = 0; ; ++i) {
if ('\0' == key[i]) {
return ('=' == string[i]);
} else if ('\0' == string[i]) {
return false;
} else if (string[i] != key[i]) {
return false;
}
}
}
static int _envp_append(envp_t *envp, char *string) {
/* find the end */
envp_t p = *envp;
size_t i = 0;
while (NULL != p[i]) i++;
/* make space for one more element */
p = realloc(p, ((i+2) * sizeof(char *)));
if (NULL == p) {
return -1;
}
*envp = p;
/* append element */
p[i+1] = 0;
p[i] = string;
return 0;
}
static int _envp_replace(char **old, char *new) {
char *oldv = *old;
*old = new;
free(oldv);
return 0;
}
envp_t *envp_alloc(void) {
envp_t envp = calloc(1, sizeof(*envp));
envp_t *envpp = malloc(sizeof(envpp));
*envpp = envp;
return envpp;
}
envp_t *envp_dup(void) {
envp_t *envp = envp_alloc();
for (size_t i = 0; NULL != environ[i]; ++i) {
(void)_envp_append(envp, strdup(environ[i]));
}
return envp;
}
static char **_envp_find_elem(envp_t envp, const char *restrict name) {
for (size_t i = 0; NULL != envp[i]; ++i) {
if (_envp_string_match_key(envp[i], name)) {
return &envp[i];
}
}
return NULL;
}
static char *_envp_get_elem(envp_t envp, const char *restrict name) {
char **elem = _envp_find_elem(envp, name);
return (elem ? *elem : NULL);
}
char *envp_get(envp_t *envp, const char *name) {
#if !HAVE_CC_NONNULL_CHECK
if (NULL == envp) return NULL;
#endif
char *elem = _envp_get_elem(*envp, name);
if (NULL != elem) {
elem = strchr(elem, '=');
if (NULL != elem) elem++; /* skip over = */
}
return elem;
}
int envp_put(envp_t *envp, char *string) {
#if !HAVE_CC_NONNULL_CHECK
if (NULL == envp || NULL == string) return -1;
#endif
char envname[strchr(string, '=')-string+1];
strncpy(envname, string, sizeof(envname));
char **elem = _envp_find_elem(*envp, envname);
if (NULL != elem) {
return _envp_replace(elem, string);
} else {
return _envp_append(envp, string);
}
}
int envp_set(
envp_t *envp, const char *restrict envname, const char *restrict envval,
bool overwrite) {
char **elem = _envp_find_elem(*envp, envname);
char *string = NULL;
if (NULL == elem || overwrite) {
size_t slen = (strlen(envname) + strlen (envval) + 2);
string = malloc(slen * sizeof(char));
snprintf(string, slen, "%s=%s", envname, envval);
}
if (NULL != elem) {
if (overwrite) {
return _envp_replace(elem, string);
} else {
/* no change */
return 0;
}
} else {
return _envp_append(envp, string);
}
}
int envp_unset(envp_t *envp, const char *restrict name) {
size_t i;
/* find element */
for (i = 0; NULL != (*envp)[i]; ++i) {
if (_envp_string_match_key((*envp)[i], name)) {
break;
}
}
char *elem = (*envp)[i];
if (NULL == elem) {
/* not found -> ok */
return 0;
}
/* shift rest of elements */
for (; NULL != (*envp)[i]; ++i) {
(*envp)[i] = (*envp)[i+1];
}
/* delete match */
free(elem);
return 0;
}
void envp_merge(envp_t *dest, envp_t *const src) {
#if !HAVE_CC_NONNULL_CHECK
if (NULL == src || NULL == dest) return;
#endif
for (size_t i = 0; NULL != (*src)[i]; ++i) {
envp_put(dest, strdup((*src)[i]));
}
}
void envp_print(envp_t *envp, FILE *restrict stream) {
for (size_t i = 0; NULL != (*envp)[i]; ++i) {
fprintf(stream, "%s\n", (*envp)[i]);
}
}
void envp_free(envp_t *envp) {
for (size_t i = 0; NULL != (*envp)[i]; ++i) {
free((*envp)[i]);
}
free(*envp);
free(envp);
}
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