rewrite string accumilation to use a dynamic array instead of many reallocations

This commit is contained in:
2025-04-29 21:44:19 +02:00
parent d925462c4d
commit 8449c58ab5

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@@ -3,6 +3,8 @@
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -26,37 +28,55 @@ struct opts opts = {
COLOUR8_BLUE, // colour for the J shape
};
/* contains the basic structure for a string */
struct str {
char* dat; // pointer to the string data
unsigned cap; // current string capacity
};
struct proc_buf_dat {
struct str pkey; // contains a memory address for storing the key string, the memory stored grows via 2ˣ
struct str pval; // contains a memory address for storing the val string, the memory stored grows via 2ˣ
char const* restrict key; // the pointer for the start of the key
char const* restrict val; // the pointer for the start of the value
char* restrict pkey; // pointer to a malloc'd key
char* restrict pval; // pointer to a malloc'd val
unsigned key_len; // string length of the key data
unsigned val_len; // string length of the value data
unsigned pkey_len; // string length of the malloc'd key when they got malloc'd
unsigned pval_len; // string length of the malloc'd val when they got malloc'd
unsigned key_len; // string length of the key data
unsigned val_len; // string length of the value data
bool feq; // whether we've found the equal sign and are looking for the value
bool eol; // whether we've reached the end of the line/string, so we don't read what should be comments as data, etc.
bool nodat; // whether we are done and can just look for an EOL indicator
};
/* use malloc to append src to the end of dest.
if *dest == NULL, memory is allocated, otherwise it is reallocated.
/* appends src onto dest.dat, if test.dat hasn't been allocated, or does not have enough space.
The size is the nearest 2ˣ rounded-up value of src_len.
returns 0 upon success, 1 upon failure. */
__attribute__((nonnull(1, 3))) static inline int str_put(char* restrict* restrict dest, size_t dest_len, char const* restrict src, size_t src_len) {
if (!*dest) {
*dest = malloc(src_len + 1);
if (!*dest) return 1;
} else {
assert(src_len > dest_len); // sanity check
void* ptr = realloc(*dest, src_len + 1);
if (!ptr) return 1;
*dest = ptr;
__attribute__((nonnull(1, 3))) static inline int str_put(struct str* restrict dest, size_t dest_len, char const* restrict src, size_t src_len) {
// check if (re)allocation needs to occur
if (dest->cap <= src_len) { // check for equality as well due to `\0`
dest->cap = src_len; // using src_len as-is, since it is string length, thus already one short.
for (unsigned i = 1; i < SIZE_WIDTH; i <<= 1) // then loop through each 2ˣ bit in size_t
dest->cap |= dest->cap >> i; // OR together the shifted result (shifted 1, 2, 4, 8, 16 on 32 bit systems)
dest->cap++; // round to the most significant bit (0111 -> 1000)
// (re)allocate the array
if (!dest->dat) {
dest->dat = malloc(dest->cap); // allocate memory for this capacity
if (!dest->dat) return 1; // return 1 upon failure
} else {
void* ptr = realloc(dest->dat, dest->cap); // reallocate to the new capacity
if (!ptr) {
free(dest->dat); // free up resources by the old (still valid) pointer, and return failure
return 1;
}
dest->dat = ptr;
}
}
// copy the missing data to the end of the destination
memcpy(*dest + dest_len, src, src_len - dest_len);
(*dest)[src_len] = '\0'; // null-terminate the destination
memcpy(dest->dat + dest_len, src, src_len - dest_len);
dest->dat[src_len] = '\0'; // null-terminate the destination
return 0;
}
@@ -65,9 +85,11 @@ __attribute__((nonnull(1, 3))) static inline int str_put(char* restrict* restric
static void proc_buf(char const* restrict buf, struct proc_buf_dat* restrict dat) {
// reset if EOL has been reached
if (dat->eol) {
free(dat->pkey);
free(dat->pval);
*dat = (struct proc_buf_dat){0};
// zero-initialize all except the pointers; keep the pointers.
*dat = (struct proc_buf_dat){
.pkey = dat->pkey,
.pval = dat->pval,
};
}
// loop through each character
@@ -103,10 +125,12 @@ static void proc_buf(char const* restrict buf, struct proc_buf_dat* restrict dat
// allocate memory for the resulting string(s)
if (dat->pval_len < dat->val_len) { // first check this condition, as key won't have changed if this is true
str_put(&dat->pval, dat->pval_len, dat->val, dat->val_len);
if (str_put(&dat->pval, dat->pval_len, dat->val, dat->val_len))
fatal(ERROR_STD_MEMORY_INIT, __FILE_NAME__, __LINE__, "something went wrong when attempting to allocate space for the option string");
dat->pval_len = dat->val_len;
} else if (dat->pkey_len < dat->key_len) {
str_put(&dat->pkey, dat->pkey_len, dat->key, dat->key_len);
if (str_put(&dat->pkey, dat->pkey_len, dat->key, dat->key_len))
fatal(ERROR_STD_MEMORY_INIT, __FILE_NAME__, __LINE__, "something went wrong when attempting to allocate space for the option string");
dat->pkey_len = dat->key_len;
}
}
@@ -126,15 +150,24 @@ static void proc_buf(char const* restrict buf, struct proc_buf_dat* restrict dat
/* attempts to load the options,
returns 1 upon failure */
int load_opts(void) {
if (!path_opts) return 1;
if (!path_opts) {
error("the variable to the path to the options failed to initialize");
return 1;
}
if (faccess(path_opts, FA_R)) {
error("attempted to load opts file, but the given path wasn't readable");
warn("attempted to load '%s', but the given path wasn't readable or doesn't exist", path_opts);
return 1;
}
// open the file in read mode
FILE* fptr = fopen(path_opts, "r");
if (!fptr) return 1;
if (!fptr) {
error("failed to open '%s'", path_opts);
return 1;
}
debug("loading options configuration from '%s'...", path_opts);
struct proc_buf_dat dat = {0};
@@ -143,22 +176,23 @@ int load_opts(void) {
while (fgets(buf, BUF_SIZE, fptr)) {
// process the data in the current buffer
proc_buf(buf, &dat);
if (dat.pkey) debug("key: '%s'", dat.pkey);
if (dat.pval) debug("val: '%s'", dat.pval);
if (dat.pkey.dat) debug("key: '%s'", dat.pkey.dat);
if (dat.pval.dat) debug("val: '%s'", dat.pval.dat);
// ignore if EOL hasn't been reached yet, due to the built up data possibly being incomplete
if (!dat.eol) continue;
if (!dat.pkey || !dat.pval) continue;
else if (!!strcmp(dat.pkey, "sensitivity")) load_opt(float, opts.sensitivity, dat.pkey, dat.pval, strtof32, );
else if (!!strcmp(dat.pkey, "sensitivity_roll")) load_opt(float, opts.sensitivity_roll, dat.pkey, dat.pval, strtof32, );
else if (!!strcmp(dat.pkey, "colour_O")) load_opt(colour8, opts.colour_O, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_I")) load_opt(colour8, opts.colour_I, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_S")) load_opt(colour8, opts.colour_S, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_Z")) load_opt(colour8, opts.colour_Z, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_T")) load_opt(colour8, opts.colour_T, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_L")) load_opt(colour8, opts.colour_L, dat.pkey, dat.pval, strtol, , 16);
else if (!!strcmp(dat.pkey, "colour_J")) load_opt(colour8, opts.colour_J, dat.pkey, dat.pval, strtol, , 16);
else error("unknown key-value pair: '%s = %s'", dat.pkey, dat.pval);
if (!dat.pkey.dat || !dat.pval.dat) continue;
else if (!!strcmp(dat.pkey.dat, "sensitivity")) load_opt(float, opts.sensitivity, dat.pkey.dat, dat.pval.dat, strtof32, );
else if (!!strcmp(dat.pkey.dat, "sensitivity_roll")) load_opt(float, opts.sensitivity_roll, dat.pkey.dat, dat.pval.dat, strtof32, );
else if (!!strcmp(dat.pkey.dat, "colour_O")) load_opt(colour8, opts.colour_O, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_I")) load_opt(colour8, opts.colour_I, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_S")) load_opt(colour8, opts.colour_S, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_Z")) load_opt(colour8, opts.colour_Z, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_T")) load_opt(colour8, opts.colour_T, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_L")) load_opt(colour8, opts.colour_L, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else if (!!strcmp(dat.pkey.dat, "colour_J")) load_opt(colour8, opts.colour_J, dat.pkey.dat, dat.pval.dat, strtol, , 16);
else error("unknown key-value pair: '%s = %s'", dat.pkey.dat, dat.pval.dat);
// TODO: load opts from the file
// the options shall be loaded as key-value-pairs
// lines starting with # are seen as comments
@@ -166,8 +200,8 @@ int load_opts(void) {
// if a field couldn't be parsed the program is not allowed to fail. I'd say we fix the field for the user.
}
free(dat.pkey);
free(dat.pval);
free(dat.pkey.dat);
free(dat.pval.dat);
fclose(fptr);
return 0;
}