libakstdlib/include/akstdlib.h

#ifndef _AKSTDLIB_H_
#define _AKSTDLIB_H_

#include <akerror.h>

/*
 * libakerror 1.0.0 is the floor. That release moved the status-name table into a
 * private registry -- AKERR_MAX_ERR_VALUE and __AKERR_ERROR_NAMES are gone, the
 * registry entry points raise akerr_ErrorContext * instead of returning int, and
 * the library gained an soname -- so a translation unit that pairs this header
 * with a pre-1.0.0 akerror.h is an ABI mismatch, not just a compile problem.
 *
 * libakerror publishes no version macro, so this feature-tests on
 * AKERR_FIRST_CONSUMER_STATUS, which that release introduced, rather than on a
 * version number that does not exist. Without the guard a stale installed header
 * fails much further in, as a pile of unrelated errors inside src/stdlib.c.
 *
 * See deps/libakerror/UPGRADING.md.
 */
#ifndef AKERR_FIRST_CONSUMER_STATUS
#error "libakstdlib requires libakerror >= 1.0.0: the akerror.h on the include path predates the status registry. Rebuild and reinstall libakerror."
#endif

/*
 * AKSL_VERSION_MAJOR/MINOR/PATCH/STRING/NUMBER and AKSL_VERSION_SONAME.
 * Generated by CMake from include/akstdlib_version.h.in, which is why there is
 * no such file in the source tree -- it is configured into the build tree and
 * installed alongside this header.
 */
#include <akstdlib_version.h>

/*
 * What this header needs in its own declarations, and no more:
 *   stdio.h   FILE
 *   stddef.h  size_t
 *   stdint.h  uint32_t
 *   stdarg.h  va_list, for the v* forms of the formatted-output wrappers
 *
 * It used to pull in stdlib.h and string.h as well, which nothing here needs and
 * which every consumer then got whether it wanted them or not. stddef.h in place
 * of stdlib.h is the same size_t at a fraction of the namespace. TODO.md 2.2.16.
 */
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
/* off_t, for the aksl_fseeko/aksl_ftello pair. POSIX, like aksl_realpath. */
#include <sys/types.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Restore the compile-time format/argument checking that callers otherwise lose
 * by going through a variadic wrapper: without it, printf("%d", "str") is caught
 * and aksl_printf(&n, "%d", "str") is not. TODO.md 2.2.5.
 */
#if defined(__GNUC__) || defined(__clang__)
#define AKSL_PRINTF_FORMAT(__fmt_index, __first_arg)			\
    __attribute__((format(printf, __fmt_index, __first_arg)))
#define AKSL_SCANF_FORMAT(__fmt_index, __first_arg)			\
    __attribute__((format(scanf, __fmt_index, __first_arg)))
#else
#define AKSL_PRINTF_FORMAT(__fmt_index, __first_arg)
#define AKSL_SCANF_FORMAT(__fmt_index, __first_arg)
#endif

typedef struct aksl_ListNode {
    void *data;
    struct aksl_ListNode *next;
    struct aksl_ListNode *prev;
} aksl_ListNode;

typedef struct aksl_TreeNode {
    struct aksl_TreeNode *parent;
    struct aksl_TreeNode *left;
    struct aksl_TreeNode *right;
    void *leaf;
} aksl_TreeNode;

#define AKSL_TREE_SEARCH_BFS           0    /** Breadth-first (left child before right) search mode for tree nodes */
#define AKSL_TREE_SEARCH_BFS_RIGHT     1    /** Breadth-first, right child before left, search mode for tree nodes */
#define AKSL_TREE_SEARCH_DFS           2    /** Alias for AKSL_TREE_SEARCH_DFS_PREORDER */
#define AKSL_TREE_SEARCH_DFS_PREORDER  2    /** Depth first pre-order (root, left, right) search mode for tree nodes */
#define AKSL_TREE_SEARCH_DFS_INORDER   3    /** Depth first in-order (left, root, right) search mode for tree nodes */
#define AKSL_TREE_SEARCH_DFS_POSTORDER 4    /** Depth first post-order (left, right, root) search mode for tree nodes */
#define AKSL_TREE_SEARCH_VISIT         5    /** Visit the node and stop; do not traverse the children */

/*
 * How deep aksl_tree_iterate will walk before raising AKERR_OUTOFBOUNDS.
 *
 * This is a real limit, not a formality: the depth-first walk is recursive, so
 * without it a degenerate chain overflows the stack and a child pointing back at
 * an ancestor recurses until the process dies. 256 is far past any balanced tree
 * that fits in memory (2^256 nodes) and comfortably short of a stack overflow,
 * so in practice it only ever rejects the degenerate shapes it exists to reject.
 *
 * It also sizes the ancestor buffer aksl_tree_iterate keeps on its own stack --
 * one pointer per level, so raising it costs 8 bytes of stack per level.
 */
#define AKSL_TREE_MAX_DEPTH 256

/*
 * Head/tail/length container. aksl_list_append has to walk the list to find its
 * tail, so building n nodes with it is O(n^2); the container makes that O(1) and
 * makes the length free. It owns no memory -- the nodes are still the caller's.
 */
typedef struct aksl_List {
    aksl_ListNode *head;
    aksl_ListNode *tail;
    size_t length;
} aksl_List;

typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_ListNodeIterator)(aksl_ListNode *node, void *data);
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_TreeNodeIterator)(aksl_TreeNode *node, void *data);
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_AllocFunc)(size_t size, void **dest);
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_FreeFunc)(void *ptr);
/* Reports its answer through *matched (non-zero to accept) and may raise. */
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_ListNodePredicate)(aksl_ListNode *node, void *data, int *matched);
/* Negative, zero or positive through *dest, as strcmp(3) has it. */
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_TreeCompareFunc)(void *a, void *b, int *dest);
typedef akerr_ErrorContext AKERR_NOIGNORE *(*aksl_HashMapIterator)(const char *key, void *value, void *data);

/*
 * Version of the shared library actually loaded, as opposed to the
 * AKSL_VERSION_* macros above, which record what the caller was *compiled*
 * against. The two differ exactly when a stale libakstdlib.so is on the loader
 * path, which is the failure these entry points exist to name.
 *
 * All three pointers are required; this library treats a NULL out-param as a
 * caller error rather than as "don't care" (so does aksl_free).
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_version(int *major, int *minor, int *patch);

/*
 * The loaded library's version as "MAJOR.MINOR.PATCH", and its soname. Neither
 * can fail -- they return pointers to string literals in the library's own
 * .rodata -- so they return the string directly rather than an error context,
 * the same exception akerr_name_for_status() makes for the same reason.
 */
const char *aksl_version_string(void);
const char *aksl_version_soname(void);

/*
 * Compare the caller's compiled-in version against the loaded library's.
 * Compatibility is defined as "same soname", so pre-1.0 both major and minor
 * must match and patch is ignored; from 1.0 only major will matter. Raises
 * AKERR_VALUE naming both versions on a mismatch.
 *
 * Call it through AKSL_VERSION_CHECK() below rather than directly. The macro
 * expands at *your* call site, so it captures the AKSL_VERSION_* the caller was
 * built with; the function compares them against the values baked into the
 * library. Passing the numbers by hand defeats the entire mechanism.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_version_check(int major, int minor, int patch);

#define AKSL_VERSION_CHECK()						\
    aksl_version_check(AKSL_VERSION_MAJOR, AKSL_VERSION_MINOR, AKSL_VERSION_PATCH)

/*
 * Stream I/O.
 *
 * fread and fwrite take a required size_t *nmemb_out. It is always written --
 * including on the failure paths -- so a caller who gets AKERR_EOF can find out
 * how much data arrived before the stream ran out, which is the whole point of
 * distinguishing EOF from an error. A transfer that comes up short with no
 * stream error set is AKERR_IO, not silent success.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_fopen(const char *pathname, const char *mode, FILE **fp);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fread(void *ptr, size_t size, size_t nmemb, FILE *stream, size_t *nmemb_out);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fwrite(const void *ptr, size_t size, size_t nmemb, FILE *fp, size_t *nmemb_out);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fclose(FILE *stream);

/*
 * Memory. aksl_malloc and aksl_calloc reject a zero-size request outright rather
 * than reporting whatever errno happened to hold when malloc(0) returned NULL.
 * aksl_realloc takes the pointer by reference and leaves it valid and untouched
 * on failure, which is realloc(3)'s classic leak closed off.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_malloc(size_t size, void **dst);
akerr_ErrorContext AKERR_NOIGNORE *aksl_calloc(size_t nmemb, size_t size, void **dst);
akerr_ErrorContext AKERR_NOIGNORE *aksl_realloc(void **ptr, size_t size);
akerr_ErrorContext AKERR_NOIGNORE *aksl_free(void *ptr);
akerr_ErrorContext AKERR_NOIGNORE *aksl_freep(void **ptr);
akerr_ErrorContext AKERR_NOIGNORE *aksl_memset(void *s, int c, size_t n);
/* Overlapping ranges are AKERR_VALUE, not undefined behaviour; use aksl_memmove. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_memcpy(void *d, const void *s, size_t n);
akerr_ErrorContext AKERR_NOIGNORE *aksl_memmove(void *d, const void *s, size_t n);
akerr_ErrorContext AKERR_NOIGNORE *aksl_memcmp(const void *a, const void *b, size_t n, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_memchr(const void *s, int c, size_t n, void **dest);

/*
 * Formatted output. *count is the byte count written excluding the terminating
 * NUL, and is 0 on every failure path.
 *
 * There is no aksl_sprintf. It wrapped vsprintf, which cannot be bounded, and an
 * error-handling wrapper around an unbounded write is the sharp edge this
 * library exists to remove. aksl_snprintf replaces it and treats truncation as
 * AKERR_OUTOFBOUNDS rather than as a short success.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_printf(int *count, const char *restrict format, ...) AKSL_PRINTF_FORMAT(2, 3);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fprintf(int *count, FILE *restrict stream, const char *restrict format, ...) AKSL_PRINTF_FORMAT(3, 4);
akerr_ErrorContext AKERR_NOIGNORE *aksl_snprintf(int *count, char *restrict str, size_t size, const char *restrict format, ...) AKSL_PRINTF_FORMAT(4, 5);

akerr_ErrorContext AKERR_NOIGNORE *aksl_vprintf(int *count, const char *restrict format, va_list args);
akerr_ErrorContext AKERR_NOIGNORE *aksl_vfprintf(int *count, FILE *restrict stream, const char *restrict format, va_list args);
akerr_ErrorContext AKERR_NOIGNORE *aksl_vsnprintf(int *count, char *restrict str, size_t size, const char *restrict format, va_list args);

/*
 * String to number.
 *
 * These are strict, unlike the libc functions they are named for:
 *
 *   no digits consumed          ->  AKERR_VALUE
 *   trailing junk, endptr NULL  ->  AKERR_VALUE
 *   value outside the type      ->  ERANGE
 *
 * and *dest is 0 on every failure. Pass a non-NULL endptr to opt out of the
 * trailing-junk check and read a number off the front of a longer string.
 *
 * The ato* forms are aksl_strto* with base 10 and a NULL endptr, so the whole
 * string must be a number. "0x10" is AKERR_VALUE through aksl_atoi -- base 10
 * stops at the 'x' -- and 16 through aksl_strtol(nptr, NULL, 0, &dest).
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtol(const char *nptr, char **endptr, int base, long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtoll(const char *nptr, char **endptr, int base, long long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtoul(const char *nptr, char **endptr, int base, unsigned long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtoull(const char *nptr, char **endptr, int base, unsigned long long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtod(const char *nptr, char **endptr, double *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtof(const char *nptr, char **endptr, float *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtold(const char *nptr, char **endptr, long double *dest);

akerr_ErrorContext AKERR_NOIGNORE *aksl_atoi(const char *nptr, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_atol(const char *nptr, long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_atoll(const char *nptr, long long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_atof(const char *nptr, double *dest);

/*
 * realpath(3). `buflen` must be at least PATH_MAX, because realpath(3) offers no
 * way to bound its own write -- an undersized buffer is AKERR_OUTOFBOUNDS rather
 * than a buffer overflow. aksl_realpath_alloc sizes and allocates the result
 * instead; *dest is then the caller's to release with aksl_free.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_realpath(const char *restrict path, char *restrict resolved_path, size_t buflen);
akerr_ErrorContext AKERR_NOIGNORE *aksl_realpath_alloc(const char *restrict path, char **dest);

/*
 * djb2. Length-driven, so embedded NUL bytes hash like any other byte; bytes
 * >= 0x80 are read as unsigned, so the result matches canonical djb2 and does
 * not depend on whether plain char is signed on the target.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strhash_djb2(const char *str, size_t len, uint32_t *hashval);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strhash_djb2_str(const char *str, uint32_t *hashval);

/* ---------------------------------------------------------------------- */
/* Strings -- src/string.c                                                */
/* ---------------------------------------------------------------------- */

/*
 * Two conventions run through this whole section.
 *
 * The copying and concatenating functions take the size of the destination
 * buffer, even the ones named after libc functions that do not. strcpy(3) and
 * strcat(3) cannot be called safely without knowing how much room there is, so
 * a wrapper that took the same arguments would be an error-handling wrapper
 * around a buffer overflow. dstsize is the whole buffer including the
 * terminator -- pair `char buf[64]` with `sizeof(buf)`. Truncation is
 * AKERR_OUTOFBOUNDS, and nothing is written when it happens, so ignoring the
 * status leaves an empty string rather than a plausible-looking prefix.
 *
 * The searching functions answer through an out-param, and finding nothing is a
 * successful answer of NULL rather than an error. The result points into the
 * caller's own string and must not be freed.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strlen(const char *s, size_t *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strnlen(const char *s, size_t maxlen, size_t *dest);

akerr_ErrorContext AKERR_NOIGNORE *aksl_strcpy(char *dst, size_t dstsize, const char *src);
/* Always terminates, and never NUL-pads to n; strncpy(3) does both the other way. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strncpy(char *dst, size_t dstsize, const char *src, size_t n);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strcat(char *dst, size_t dstsize, const char *src);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strncat(char *dst, size_t dstsize, const char *src, size_t n);

/* *dest is the caller's, to release with aksl_free or aksl_freep. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strdup(const char *s, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strndup(const char *s, size_t n, char **dest);

akerr_ErrorContext AKERR_NOIGNORE *aksl_strcmp(const char *a, const char *b, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strncmp(const char *a, const char *b, size_t n, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strcasecmp(const char *a, const char *b, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strncasecmp(const char *a, const char *b, size_t n, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strcoll(const char *a, const char *b, int *dest);

akerr_ErrorContext AKERR_NOIGNORE *aksl_strchr(const char *s, int c, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strrchr(const char *s, int c, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strstr(const char *haystack, const char *needle, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strcasestr(const char *haystack, const char *needle, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strpbrk(const char *s, const char *accept, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strspn(const char *s, const char *accept, size_t *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strcspn(const char *s, const char *reject, size_t *dest);

/*
 * The reentrant tokeniser only. strtok(3) keeps its state in a hidden static,
 * so two interleaved tokenisations corrupt each other silently; it is not
 * wrapped. Running out of tokens is success with *dest NULL.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strtok_r(char *str, const char *delim, char **saveptr, char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strsep(char **stringp, const char *delim, char **dest);

/*
 * The message for a status, into the caller's buffer. Knows this library's own
 * statuses as well as errno values, which strerror_r(3) could not.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strerror(int status, char *buf, size_t buflen);

/* ---------------------------------------------------------------------- */
/* Streams -- src/stream.c                                                */
/* ---------------------------------------------------------------------- */

/*
 * Where a function has a genuine "nothing more to read" outcome, that is
 * AKERR_EOF rather than AKERR_IO, so a read loop can tell the end of its input
 * from the failure of it. That applies to aksl_fgetc, aksl_fgets, aksl_getline,
 * aksl_getdelim and aksl_fscanf.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_fseek(FILE *stream, long offset, int whence);
akerr_ErrorContext AKERR_NOIGNORE *aksl_ftell(FILE *stream, long *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_rewind(FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fseeko(FILE *stream, off_t offset, int whence);
akerr_ErrorContext AKERR_NOIGNORE *aksl_ftello(FILE *stream, off_t *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fgetpos(FILE *stream, fpos_t *pos);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fsetpos(FILE *stream, const fpos_t *pos);

/* NULL stream means "every output stream", as in fflush(3); it is not an error. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_fflush(FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_setvbuf(FILE *stream, char *buf, int mode, size_t size);

akerr_ErrorContext AKERR_NOIGNORE *aksl_fgetc(FILE *stream, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fputc(int c, FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_ungetc(int c, FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fgets(char *s, size_t size, FILE *stream, size_t *len_out);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fputs(const char *s, FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_getline(char **lineptr, size_t *n, FILE *stream, size_t *len_out);
akerr_ErrorContext AKERR_NOIGNORE *aksl_getdelim(char **lineptr, size_t *n, int delim, FILE *stream, size_t *len_out);

akerr_ErrorContext AKERR_NOIGNORE *aksl_feof(FILE *stream, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_ferror(FILE *stream, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_clearerr(FILE *stream);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fileno(FILE *stream, int *dest);

akerr_ErrorContext AKERR_NOIGNORE *aksl_freopen(const char *pathname, const char *mode, FILE *stream, FILE **fp);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fdopen(int fd, const char *mode, FILE **fp);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tmpfile(FILE **fp);

/*
 * The scanf family takes the number of conversions the caller expects, because
 * comparing scanf(3)'s return against that number by hand at every call site is
 * the check everyone eventually forgets -- and forgetting it leaves the
 * unassigned arguments holding whatever they held before. Anything short of
 * `expected` is AKERR_VALUE. Pass 0 to opt out and read *assigned yourself.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_sscanf(const char *str, const char *format, int expected, int *assigned, ...) AKSL_SCANF_FORMAT(2, 5);
akerr_ErrorContext AKERR_NOIGNORE *aksl_fscanf(FILE *stream, const char *format, int expected, int *assigned, ...) AKSL_SCANF_FORMAT(2, 5);
akerr_ErrorContext AKERR_NOIGNORE *aksl_vsscanf(const char *str, const char *format, int expected, int *assigned, va_list args);
akerr_ErrorContext AKERR_NOIGNORE *aksl_vfscanf(FILE *stream, const char *format, int expected, int *assigned, va_list args);

akerr_ErrorContext AKERR_NOIGNORE *aksl_remove(const char *pathname);
akerr_ErrorContext AKERR_NOIGNORE *aksl_rename(const char *oldpath, const char *newpath);
/*
 * The template is rewritten in place, so it must be a writable buffer ending in
 * six literal X characters -- a string literal is a segfault, and that is
 * AKERR_VALUE here rather than a crash.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_mkstemp(char *template_, int *fd);
akerr_ErrorContext AKERR_NOIGNORE *aksl_mkdtemp(char *template_);

// Linked list functions
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_node_init(aksl_ListNode *node, void *data);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_append(aksl_ListNode *list, aksl_ListNode *obj);
/*
 * `head` is required. Popping the head node has to move the caller's own head
 * pointer, and there is no way to do that from a node pointer alone -- the old
 * one-argument form left the caller aimed at a detached node.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_pop(aksl_ListNode **head, aksl_ListNode *node);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_iterate(aksl_ListNode *list, aksl_ListNodeIterator iter, void *data);

// Tree functions
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_node_init(aksl_TreeNode *node, void *leaf);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_iterate(aksl_TreeNode *root, aksl_TreeNodeIterator iter, aksl_AllocFunc lalloc, aksl_FreeFunc lfree, uint8_t searchmode, void *data);

/* ---------------------------------------------------------------------- */
/* Collections -- src/collections.c                                       */
/* ---------------------------------------------------------------------- */

/*
 * Nothing in this section allocates unless its name says so. The list and tree
 * functions relink nodes the caller already owns, and the *_free_all forms take
 * the free function to use -- pass NULL for aksl_free -- so a caller drawing
 * from a fixed pool can hand over its own. Only aksl_strbuf_* owns memory.
 *
 * The bare-node list functions take the head by reference wherever the head
 * itself can move, which is the case a caller doing it by hand gets wrong.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_prepend(aksl_ListNode **head, aksl_ListNode *obj);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_insert_after(aksl_ListNode *node, aksl_ListNode *obj);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_insert_before(aksl_ListNode **head, aksl_ListNode *node, aksl_ListNode *obj);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_length(aksl_ListNode *head, size_t *dest);
/* NULL and success when nothing matches, as everywhere else in this library. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_find(aksl_ListNode *head, aksl_ListNodePredicate pred, void *data, aksl_ListNode **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_reverse(aksl_ListNode **head);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_concat(aksl_ListNode *head, aksl_ListNode *other);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_free_all(aksl_ListNode **head, aksl_FreeFunc lfree);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_iterate_reverse(aksl_ListNode *tail, aksl_ListNodeIterator iter, void *data);

/* The tracked container. push/unshift are O(1); length is a field, not a walk. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_init(aksl_List *list);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_push(aksl_List *list, aksl_ListNode *obj);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_unshift(aksl_List *list, aksl_ListNode *obj);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_remove(aksl_List *list, aksl_ListNode *node);
akerr_ErrorContext AKERR_NOIGNORE *aksl_list_clear(aksl_List *list, aksl_FreeFunc lfree);

/*
 * An unbalanced binary search tree. Inserting already-sorted data gives a
 * degenerate chain, which the traversal then refuses past AKSL_TREE_MAX_DEPTH --
 * bounded rather than dangerous, but this is not a balanced tree and does not
 * claim to be. These are the functions that set and read aksl_TreeNode.parent.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_insert(aksl_TreeNode **root, aksl_TreeNode *node, aksl_TreeCompareFunc cmp);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_find(aksl_TreeNode *root, void *leaf, aksl_TreeCompareFunc cmp, aksl_TreeNode **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_remove(aksl_TreeNode **root, aksl_TreeNode *node);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_height(aksl_TreeNode *root, int *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_count(aksl_TreeNode *root, size_t *dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_tree_free_all(aksl_TreeNode **root, aksl_FreeFunc lfree);

/*
 * FNV-1a alongside djb2. It XORs then multiplies rather than multiplying then
 * adding, which mixes the low bits better on short keys that share a prefix --
 * which is what identifiers in a symbol table look like.
 */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strhash_fnv1a(const char *str, size_t len, uint32_t *hashval);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strhash_fnv1a_str(const char *str, uint32_t *hashval);

/*
 * Fixed-capacity string-keyed hash map: open addressing, linear probing, the
 * caller's slot array, keys copied into the slots so the map owns them.
 *
 * It refuses rather than resizes when full, deliberately. A table that
 * reallocates is a table whose entry pointers move underneath anything holding
 * one; a table that cannot grow has a worst case you can state. The cost is that
 * the caller sizes it, which is why init takes the array rather than making one.
 */
#define AKSL_HASHMAP_MAX_KEY        64
#define AKSL_HASHMAP_SLOT_EMPTY     0   /** Never used; ends a probe chain */
#define AKSL_HASHMAP_SLOT_OCCUPIED  1   /** Holds a live key and value */
#define AKSL_HASHMAP_SLOT_DELETED   2   /** Tombstone; reusable, but does not end a chain */

typedef struct aksl_HashEntry {
    char key[AKSL_HASHMAP_MAX_KEY];
    void *value;
    uint8_t state;
} aksl_HashEntry;

typedef struct aksl_HashMap {
    aksl_HashEntry *slots;
    size_t capacity;
    size_t count;
} aksl_HashMap;

akerr_ErrorContext AKERR_NOIGNORE *aksl_hashmap_init(aksl_HashMap *map, aksl_HashEntry *slots, size_t capacity);
akerr_ErrorContext AKERR_NOIGNORE *aksl_hashmap_put(aksl_HashMap *map, const char *key, void *value);
/* A missing key is *found = 0 and success; looking and not finding is not an error. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_hashmap_get(aksl_HashMap *map, const char *key, void **value, int *found);
akerr_ErrorContext AKERR_NOIGNORE *aksl_hashmap_remove(aksl_HashMap *map, const char *key, int *removed);
akerr_ErrorContext AKERR_NOIGNORE *aksl_hashmap_iterate(aksl_HashMap *map, aksl_HashMapIterator iter, void *data);

/*
 * Growable string buffer -- the one thing here that owns memory, which is what
 * makes the bounded formatting wrappers usable when the output length is not
 * known in advance. Capacity doubles, so n appends cost O(n) amortised, and the
 * contents are always NUL-terminated so aksl_strbuf_cstr is valid at any point.
 */
typedef struct aksl_StrBuf {
    char *data;
    size_t length;      /** Bytes in use, terminator not counted */
    size_t capacity;    /** Bytes allocated, terminator included */
} aksl_StrBuf;

akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_init(aksl_StrBuf *buf, size_t initial);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_append(aksl_StrBuf *buf, const char *s);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_append_bytes(aksl_StrBuf *buf, const char *s, size_t n);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_append_char(aksl_StrBuf *buf, char c);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_appendf(aksl_StrBuf *buf, const char *format, ...) AKSL_PRINTF_FORMAT(2, 3);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_vappendf(aksl_StrBuf *buf, const char *format, va_list args);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_reset(aksl_StrBuf *buf);
/* Points into the buffer; the next append invalidates it. */
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_cstr(aksl_StrBuf *buf, const char **dest);
akerr_ErrorContext AKERR_NOIGNORE *aksl_strbuf_free(aksl_StrBuf *buf);

#ifdef __cplusplus
}
#endif

#endif