Initial commit.

str.h

@@ -0,0 +1,170 @@
+
+#pragma once
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+struct str {
+    size_t len;
+    size_t cap;
+    char* data;
+};
+
+static struct str str_slice(struct str str, size_t begin, size_t end)
+{
+    return (struct str) {
+        .len = end - begin,
+        .data = str.data + begin
+    };
+}
+
+static void str_free(struct str* str)
+{
+    free(str->data);
+    str->len = 0;
+    str->cap = 0;
+}
+
+static int str_right_pad(struct str* str, char ch, size_t n)
+{
+    struct str restore = *str;
+    int retval = 0;
+
+    size_t new_len = str->len + n;
+    if (new_len > str->cap) {
+        str->cap *= 2;
+        void* tmp = realloc(str, str->cap);
+        if (!tmp) {
+            retval = -errno;
+            goto fail;
+        }
+        str->data = tmp;
+    }
+
+    for (size_t i = str->len; i < new_len; i++) {
+        str->data[i] = ch;
+    }
+    str->len = new_len;
+    return retval;
+
+fail:
+    *str = restore;
+    return retval;
+}
+
+static void str_println(struct str str, FILE* f)
+{
+    for (size_t i = 0; i < str.len; i++) {
+        fputc(str.data[i], f);
+    }
+    fputc('\n', f);
+}
+
+static int str_append(struct str* str, int ch)
+{
+    struct str restore = *str;
+    if (str->len + 1 > str->cap) {
+        str->cap *= 2;
+        void* tmp = realloc(str->data, str->cap);
+        if (!tmp) {
+            *str = restore;
+            return -1;
+        }
+        str->data = tmp;
+    }
+    str->data[str->len++] = ch;
+    return 0;
+}
+
+/* read contents from file `f` and return as str */
+static struct str read_all(FILE* f)
+{
+    struct str str = {
+        .cap = 4096,
+        .len = 0,
+        .data = NULL,
+    };
+    str.data = malloc(str.cap);
+    if (str.data == NULL) {
+        perror("malloc");
+        return (struct str) { 0 };
+    }
+
+    while (1) {
+        str.len += fread(&str.data[str.len], 1, str.cap - str.len, f);
+        if (str.len != str.cap) {
+            if (feof(f)) {
+                break;
+            } else if (ferror(f)) {
+                perror("fread");
+                goto fail;
+            } else {
+                /* programming error */
+                fprintf(stderr, "whoopsie!\n");
+                abort();
+            }
+        }
+        str.cap *= 2;
+        void* tmp = realloc(str.data, str.cap);
+        if (!tmp) {
+            perror("realloc");
+            goto fail;
+        }
+        str.data = tmp;
+    }
+
+    str.len -= 1;
+
+    /* shrink to what's needed */
+    void* tmp = realloc(str.data, str.len);
+    if (tmp) {
+        /* it's ok if shrinking fails */
+        str.data = tmp;
+        str.cap = str.len;
+    }
+
+    return str;
+
+fail:
+    free(str.data);
+    return (struct str) { 0 };
+}
+
+/* read contents from file `f`, but first apply `map` to characters and then
+ * filter them with `filter` */
+static struct str read_all_filter(FILE* f, int (*filter)(int ch), int (*map)(int ch))
+{
+    struct str str = {
+        .data = NULL,
+        .cap = 4096,
+        .len = 0,
+    };
+    str.data = malloc(str.cap);
+    if (str.data == NULL) {
+        perror("malloc");
+        goto malloc_failed;
+    }
+
+    int c;
+    while ((c = fgetc(f)) != EOF) {
+        c = map(c);
+
+        if (!filter(c)) {
+            continue;
+        }
+
+        int ok = str_append(&str, c);
+        if (ok == -1) {
+            goto fail;
+        }
+    }
+
+    return str;
+
+fail:
+    free(str.data);
+malloc_failed:
+    return (struct str) { 0 };
+}