1 files changed, 244 insertions, 0 deletions
diff --git a/src/value.c b/src/value.c
new file mode 100644
index 0000000..289aa0f
--- /dev/null
+++ b/src/value.c
@@ -0,0 +1,244 @@
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "common.h"
+#include "value.h"
+
+// TODO: add the other types
+
+// save data as a symbol
+// return 0 on sucess, < 0 on error
+static int symbol_save(char **symbol, char *data);
+// same as value_string
+static char *symbol_string(char *symbol, char *buf, size_t buf_sz);
+
+// try to save data as a literal
+// returns 0 on sucess, > 0 on fail (data isnt a possible literal),
+//         and < 0 on error
+static int literal_save(struct literal *literal, char *data);
+static void literal_free(struct literal *literal);
+// same as value_string
+static char *literal_string(struct literal *literal, char *buf, size_t buf_sz);
+
+// for a function that saves string data as a value
+#define S_FN(fn, arg) fn(arg, (char *)data)
+// for a function that saves a value as a string in buf[buf_sz]
+#define P_FN(fn, arg) fn(arg, buf, buf_sz)
+
+#define MANAGE_VALUE_TBL(X, value)                                           \
+/*  X(type,           save function,                                         \
+      how to free,                    how to save to string) */              \
+    X(VALUE_SYMBOL,   S_FN(symbol_save, &value->symbol),                     \
+      free(value->symbol),            P_FN(symbol_string, value->symbol))    \
+    X(VALUE_LITERAL,  S_FN(literal_save, &value->literal),                   \
+      literal_free(&value->literal),  P_FN(literal_string, &value->literal)) \
+//  X(VALUE_PAIR, ...)
+//  X(VALUE_LIST, ...)
+//  X(VALUE_PROC, ...)
+
+// ------ Exported Functions Implementations ------- //
+// ------------------------------------------------- //
+
+#define CASE_SAVE(type, save_func, free_func, string_func) \
+    case type: *ret = save_func; break;
+
+value_t value_create(enum value_type type, void *data, int *ret)
+{
+    value_t value = xmalloc(sizeof(struct value));
+
+    value->type = VALUE_TYPES;
+    value->references = 1;
+
+    switch(type) {
+        MANAGE_VALUE_TBL(CASE_SAVE, value);
+    default:
+        err("value_create: Unknown value type given");
+        *ret = -1;
+        break;
+    }
+
+    if(!*ret) {
+        value->type = type;
+        return value;
+    }
+
+    value_destroy(value);
+    return NULL;
+}
+
+value_t value_copy(value_t value)
+{
+    value->references++;
+    return value;
+}
+
+#define CASE_FREE(type, save_func, free_func, string_func) \
+    case type: free_func; break;
+
+void value_destroy(value_t value)
+{
+    if(!value) return;
+    if(--value->references > 0) {
+        return;
+    }
+
+
+    switch(value->type) {
+        MANAGE_VALUE_TBL(CASE_FREE, value);
+    default: break;
+    }
+
+    free(value);
+}
+
+#define CASE_STRING(type, save_func, free_func, string_func) \
+    case type: return string_func;
+
+char *value_string(value_t value, char *buf, size_t buf_sz)
+{
+    switch(value->type) {
+        MANAGE_VALUE_TBL(CASE_STRING, value);
+    default: return NULL;
+    }
+}
+
+// ---------------- Symbol Functions --------------- //
+
+static int symbol_save(char **symbol, char *data)
+{
+    size_t len = strlen(data) + 1;
+
+    *symbol = xmalloc(len);
+
+    memcpy(*symbol, data, len);
+    return 0;
+}
+
+static char *symbol_string(char *symbol, char *buf, size_t buf_sz)
+{
+    size_t len = strlen(symbol) + 1;
+    if(len> buf_sz) {
+        return NULL;
+    }
+
+    memcpy(buf, symbol, len);
+    return buf;
+}
+
+// --------------- Literal Functions --------------- //
+
+// write a value in a printf format to buf[buf_sz]
+#define EX(...) (((size_t)snprintf(buf, buf_sz, __VA_ARGS__) > buf_sz) ? NULL : buf)
+
+#define MANAGE_LITERAL_TBL(X, literal)                                         \
+/*  X(type,               how to free             how to print) */             \
+    X(LITERAL_STRING,     free(literal->string),  EX("%s",  literal->string))  \
+    X(LITERAL_NUM_INT,    ;,  EX("%ld", literal->num_int))                     \
+    X(LITERAL_NUM_FLOAT,  ;,  EX("%f",  literal->num_float))
+
+// try to convert the data to a literal
+// returns 0 on success, > 0 on fail (data isnt a literal),
+//         and < 0 on error
+static int literal_try_string(struct literal *literal, char *data);
+static int literal_try_int   (struct literal *literal, char *data);
+static int literal_try_float (struct literal *literal, char *data);
+
+// list of the try_type functions (order matters)
+typedef int (*try_func)(struct literal *, char *);
+try_func literal_try_funcs[] = {
+    literal_try_string,
+    literal_try_int,
+    literal_try_float,
+};
+
+static int literal_save(struct literal *literal, char *data)
+{
+    int ret = 0;
+
+    for(size_t i = 0; i < sizeof(literal_try_funcs)/sizeof(try_func); i++) {
+        // <= 0 means that it either failed fatally, or succeeded
+        if((ret = literal_try_funcs[i](literal, data)) <= 0) break;
+    }
+
+    return ret;
+}
+
+#define CASE_LITERAL_FREE(type, free_func, string_func) \
+    case type: free_func; break;
+
+static void literal_free(struct literal *literal)
+{
+    switch(literal->type) {
+        MANAGE_LITERAL_TBL(CASE_LITERAL_FREE, literal);
+    default: break;
+    }
+}
+
+#define CASE_LITERAL_STRING(type, free_func, string_func)    \
+    case type: return string_func;
+
+static char *literal_string(struct literal *literal, char *buf, size_t buf_sz)
+{
+    switch(literal->type) {
+        MANAGE_LITERAL_TBL(CASE_LITERAL_STRING, literal);
+    default: return NULL; break;
+    }
+}
+
+// Literal try_type functions
+
+static int literal_try_string(struct literal *literal, char *data)
+{
+    if(data[0] != '"') return 1;
+
+    literal->type = LITERAL_STRING;
+
+    size_t len = strlen(data); // no +1 needed since first character is discarded
+    literal->string = xmalloc(len);
+
+    memcpy(literal->string, data + 1, len);
+    return 0;
+}
+
+static int literal_try_int(struct literal *literal, char *data)
+{
+    errno = ERANGE + 1; // set errno to not ERANGE
+
+    char *endptr;
+    long num = strtol(data, &endptr, 10);
+
+    if(*endptr != '\0') { // the whole string isn't a number
+        return 1;
+    }
+
+    if(errno == ERANGE) {
+        warn("Given integer literal %s is outside the possible range", data);
+    }
+
+    literal->type = LITERAL_NUM_INT;
+    literal->num_int = num;
+
+    return 0;
+}
+
+static int literal_try_float (struct literal *literal, char *data)
+{
+    errno = ERANGE + 1; // set errno to not ERANGE
+
+    char *endptr;
+    float num = strtof(data, &endptr);
+
+    if(*endptr != '\0') { // the whole string isn't a number
+        return 1;
+    }
+
+    if(errno == ERANGE) {
+        warn("Given float literal %s is outside the possible range", data);
+    }
+
+    literal->type = LITERAL_NUM_FLOAT;
+    literal->num_float = num;
+
+    return 0;
+}